Observations and computations of narrow Kelvin ship wakes

OpenAIRE

Francis Noblesse; Chenliang Zhang; Jiayi He; Yi Zhu; Chenjun Yang; Wei Li

2016-01-01

Computations of far-field ship waves, based on linear potential flow theory and the Hogner approximation, are reported for monohull ships and catamarans. Specifically, far-field ship waves are computed for six monohull ships at four Froude numbers F≡V/gL=0.58, 0.68, 0.86, 1.58 and for six catamarans with nondimensional hull spacing s≡S/L=0.25 at two Froude numbers Fs≡V/gS=1 and 2.5. Here, g is the gravitational acceleration, V and L denote the ship speed and length, and S is the separation di...

Conference Proceedings for 1997 IEEE 24th International Conference on Plasma Sciences, 19 - 22 May 1997, San Diego, California

National Research Council Canada - National Science Library

Hyman, Julius

1997-01-01

This 360 page softbound publication includes the following major sections, An invitation to ICOPS'97, Catamaran Resort Hotel Floor Pinas, Officers of the IEEE Nuclear and Plasma Sciences Society, Conference Information...

IEEE Conference Record - Abstracts. 1997 IEEE International Conference on Plasma Science, 19 - 22 May 1997 San Diego, California

National Research Council Canada - National Science Library

Hyman, Julius

1997-01-01

This 360 page softbound publication includes the following major sections. An invitation to ICOPS'97, Catamaran Resort Hotel Floor Pinas, Officers of the IEEE Nuclear and Plasma Sciences Society, Conference Information...

Cost Earnings Data 2001 - American Samoa Longline

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — In 2001, 25 vessels > 50 feet in overall length joined the American Samoa longline fleet, which previously had consisted of local, small catamaran-style vessels...

High Speed Vessels to Market : Comparative Case Studies in the Passenger Trade

Science.gov (United States)

2001-08-01

The Volpe Center chose to study several existing catamarans and high speed monohulls in comparison to representative SWATH family craft, including the SLICE 400 (passenger) and SLICE 600 (passenger/90 car) variants, the former similar in size and per...

77 FR 4501 - Special Local Regulation and Safety Zone; America's Cup Sailing Events, San Francisco, CA

Science.gov (United States)

2012-01-30

... larger 72-foot catamarans (AC72), each crewed by a team of 11 competitors. The AC72 is predicted to... the proposed race area to accommodate changing weather conditions that may alter the exact orientation... competition continues, the number of races planned each day in 2013 will decrease as competitors are...

X-joints in composite sandwich panels

NARCIS (Netherlands)

Vredeveldt, A.W.; Janssen, G.Th.M.

1998-01-01

The small structural weight of fast large ships such as fast mono hulls or catamaran type of ships is of extreme importance to their success. One possible light weight structural solution is the sandwich panel with fibre reinforced laminates and a balsa, honeycomb or foam core. A severe obstacle for

Catamaran type semisubmersible platform for offshore drilling

Energy Technology Data Exchange (ETDEWEB)

Pouget, G; Chevallier, J; Hampton, G

1988-06-10

A semi-submersible oil rig which allows the vertical storage of drilling tubes and drill pipes is presented. The structure which links the floaters to the bridge consists of hollow columns forming caissons and containing means for storing tubes.

Basement of Structure, Main Power and Design Parameters of Mechanism of Removing Sections of Mechanized Sets of Knife Plane Installation

Science.gov (United States)

Sysoev, N. I.; Turuk, Yu V.; Kolesnichenko, I. Y.; Lugantsev, B. B.

2017-10-01

The reasons for the failure of the pitch stability of the knife-plane installation due to the action of extreme effort in the plane of the seam from the conveyor side on the mechanism of removing sections of mechanized sets are shown. The technique for determining this effort is presented. The constructions of the adaptive mechanisms of the removing sections of mechanized sets with the basements of catamaran type, in the constrictions of which elastic elements (rods) are used, are considered. The constructions of the mechanism of removing a section of the mechanized set with the basement of catamaran type in which the stock of the hydraulic jack is connected with the band loop through the movable rods intermediate basement with a link are worked out. The intermediate basement unloads the stock of the hydraulic jack of the moving installation from the side curving efforts, caused by the action of lateral forces in the plane of the seam on the conveyor side. It increases the reliability and efficiency of work of the knife plane mechanized complex.

Yachting Club

CERN Multimedia

Yachting Club

2012-01-01

Under a cloudless sky, the YCC ran its traditional Traversée du Lac for dinghies and catamarans last Sunday. The turn-out was not good, surprisingly: do we all take longer or more frequent holidays than your Committee anticipated? Never mind, we had a final fleet of six, even with no catamarans: three Laser 1’s (now that is a popular boat and surely a wise recent purchase for the Club), and three RS’s, respectively 400, 500 and 800 (private). Winds were light, but even with a slightly delayed start, they were strong enough for Race Officer Tom Wilkins and ResQ driver Tim Hancox to fit in two complete circuits/races. In older times, that would have been one race of two circuits, but the scoring is fairer if you get a chance to recover your first start in a second heat! Adjacent is a photo (thank you Loic Le Canderff, also doing important work on ResQ) of one of the final winners, Sandrine on Laser 1, joint first with overall regatta coordinator, Sanja: yes, surprisingly, th...

Yachting club

CERN Multimedia

Yachting club

2011-01-01

WARNING: your C key is about to expire... Good, we hoped that would draw your attention! A gentle reminder that, following the purchase of our fast, sophisticated racing catamaran Hobie Tiger Meerkat last season, your Committee decided to create a new key to reflect this, the EC (Experienced Catamaran). Those taking a C course will be assessed during a test as to whether they will gain the C key or the C plus EC key, so need only practise hard. Those - and we are many - who possess the C key from past years need to refresh our knowledge and prove our competence to sail Meerkat effectively with the EC key. This requires a few attested outings under good wind conditions, use of the gennaker, general control. And if it’s any consolation, we (remembering the Darts and then the Mysteres, and now both SL16 and Tiger) can confirm that she is really a pussycat, and really very willing to tack if you treat her right... Plan on trying for her or indeed Catapult on Thursdays, then talk to your Committee (f.i...

Amphibious Combat Vehicle: Some Acquisition Activities Demonstrate Best Practices; Attainment of Amphibious Capability to be Determined

Science.gov (United States)

2015-10-01

Defense EFV Expeditionary Fighting Vehicle EPF Expeditionary Fast Transport ESD Expeditionary Transfer Dock JCIDS Joint Capabilities...materials, propulsion, maintainability, and habitability. Production for the SC(X)R is planned to begin in 2018. Expeditionary Fast Transport ( EPF ...The EPF , formerly known as the Joint High Speed Vessel, is a commercial-based catamaran that provides heavy-lift, high-speed sealift mobility. The

Fleet Battle Experiment Juliet Final Reconstruction and Analysis Report

Science.gov (United States)

2003-04-01

8000 tons 145 Selected Vessel Statistics Joint Venture Sea SLICE Ship particulars Wave Piercing Catamaran ( CAT ) Small Waterplane Area Twin Hull (SWATH...and broadcasting capabilities. NSWC Corona used a built-in function within GCCS-M to broadcast all OTH Gold Contact (CTC) messages to a file. These...example would be the prohibition of e-mail from electronically accessing the e- 309 mail address book; thus denying many self-propagating viruses

Fifth International Conference on High Energy Density Physics

Energy Technology Data Exchange (ETDEWEB)

Beg, Farhat

2017-07-05

The Fifth International Conference on High Energy Density Physics (ICHED 2015) was held in the Catamaran Hotel in San Diego from August 23-27, 2015. This meeting was the fifth in a series which began in 2008 in conjunction with the April meeting of the American Physical Society (APS). The main goal of this conference has been to bring together researchers from all fields of High Energy Density Science (HEDS) into one, unified meeting.

High Resolution Marine Magnetic Survey of Shallow Water Littoral Area

OpenAIRE

Jacob Sharvit; Nizan Salomonski; Roger Alimi; Hovav Zafrir; Tsuriel Ram Cohen; Boris Ginzburg; Eyal Weiss

2007-01-01

The purpose of this paper is to present a system developed for detection andaccurate mapping of ferro-metallic objects buried below the seabed in shallow waters. Thesystem comprises a precise magnetic gradiometer and navigation subsystem, both installedon a non-magnetic catamaran towed by a low-magnetic interfering boat. In addition wepresent the results of a marine survey of a near-shore area in the vicinity of Atlit, a townsituated on the Mediterranean coast of Israel, about 15 km south of ...

High Resolution Marine Magnetic Survey of Shallow Water Littoral Area

OpenAIRE

Weiss, Eyal; Ginzburg, Boris; Cohen, Tsuriel Ram; Zafrir, Hovav; Alimi, Roger; Salomonski, Nizan; Sharvit, Jacob

2007-01-01

The purpose of this paper is to present a system developed for detection and accurate mapping of ferro-metallic objects buried below the seabed in shallow waters. The system comprises a precise magnetic gradiometer and navigation subsystem, both installed on a non-magnetic catamaran towed by a low-magnetic interfering boat. In addition we present the results of a marine survey of a near-shore area in the vicinity of Atlit, a town situated on the Mediterranean coast of Israel, about 15 km sout...

Concept of navigation and automatic steering of the measuring dolphin

Energy Technology Data Exchange (ETDEWEB)

Majohr, J.; Buch, T.; Korte, C. [Rostock Univ. (Germany). Inst. fuer Automatisierungstechnik

2000-07-01

The Catamaran - Measuring Dolphin (MESSIN) is an unmanned and independently operated craft having been designed for carrying out multiple measuring tasks in the field of marine research and water monitoring especially in shallow waters. An introduction to the navigation, steering and safety systems is given. Furthermore the main components of the track control system and the electronic chart system used here are shown. Results of manoeuvring tests of the MESSIN are represented. This paper gives a contribution to the field of research ''autonomous and full automated vehicle''. (orig.)

A Floating Ocean Energy Conversion Device and Numerical Study on Buoy Shape and Performance

Directory of Open Access Journals (Sweden)

Ruiyin Song

2016-05-01

Full Text Available Wave and current energy can be harnessed in the East China Sea and South China Sea; however, both areas are subject to high frequencies of typhoon events. To improve the safety of the ocean energy conversion device, a Floating Ocean Energy Conversion Device (FOECD with a single mooring system is proposed, which can be towed to avoid severe ocean conditions or for regular maintenance. In this paper, the structure of the FOECD is introduced, and it includes a catamaran platform, an oscillating buoy part, a current turbine blade, hydraulic energy storage and an electrical generation part. The numerical study models the large catamaran platform as a single, large buoy, while the four floating buoys were modeled simply as small buoys. Theoretical models on wave energy power capture and efficiency were established. To improve the suitability of the buoy for use in the FOECD and its power harvesting capability, a numerical simulation of the four buoy geometries was undertaken. The shape profiles examined in this paper are cylindrical, turbinate (V-shaped and U-shaped cone with cylinder, and combined cylinder-hemisphere buoys. Simulation results reveal that the suitability of a turbinate buoy is the best of the four types. Further simulation models were carried out by adjusting the tip radius of the turbinate buoy. Three performance criteria including suitability, power harvesting capability and energy capture efficiency were analyzed. It reveals that the turbinate buoy has almost the same power harvesting capabilities and energy capture efficiency, while its suitability is far better than that of a cylindrical buoy.

Tracking an oil slick from multiple natural sources, Coal Oil Point, California

International Nuclear Information System (INIS)

Leifer, Ira; Luyendyk, Bruce; Broderick, Kris

2006-01-01

Oil slicks on the ocean surface emitted from natural marine hydrocarbon seeps offshore from Coal Oil Point in the Santa Barbara Channel, California were tracked and sampled over a 2-h period. The objectives were to characterize the seep oil and to track its composition over time using a new sampling device, a catamaran drum sampler (CATDRUMS). The sampler was designed and developed at UCSB. Chromatograms showed that oil originating from an informally named, very active seep area, Shane Seep, primarily evolved during the first hour due to mixing with oil originating from a convergence zone slick surrounding Shane Seep. (author)

Tracking an oil slick from multiple natural sources, Coal Oil Point, California

Energy Technology Data Exchange (ETDEWEB)

Leifer, Ira [Marine Sciences Institute, University of California, Santa Barbara, CA 93106 (United States); Luyendyk, Bruce [Department of Geological Sciences, University of California, Santa Barbara, CA 93106 (United States); Broderick, Kris [Exxon/Mobil Exploration Company, 13401 N. Freeway, Houston, TX 77060 (United States)

2006-06-15

Oil slicks on the ocean surface emitted from natural marine hydrocarbon seeps offshore from Coal Oil Point in the Santa Barbara Channel, California were tracked and sampled over a 2-h period. The objectives were to characterize the seep oil and to track its composition over time using a new sampling device, a catamaran drum sampler (CATDRUMS). The sampler was designed and developed at UCSB. Chromatograms showed that oil originating from an informally named, very active seep area, Shane Seep, primarily evolved during the first hour due to mixing with oil originating from a convergence zone slick surrounding Shane Seep. (author)

Gradient flux measurements of sea–air DMS transfer during the Surface Ocean Aerosol Production (SOAP experiment

Directory of Open Access Journals (Sweden)

M. J. Smith

2018-04-01

Full Text Available Direct measurements of marine dimethylsulfide (DMS fluxes are sparse, particularly in the Southern Ocean. The Surface Ocean Aerosol Production (SOAP voyage in February–March 2012 examined the distribution and flux of DMS in a biologically active frontal system in the southwest Pacific Ocean. Three distinct phytoplankton blooms were studied with oceanic DMS concentrations as high as 25 nmol L−1. Measurements of DMS fluxes were made using two independent methods: the eddy covariance (EC technique using atmospheric pressure chemical ionization–mass spectrometry (API-CIMS and the gradient flux (GF technique from an autonomous catamaran platform. Catamaran flux measurements are relatively unaffected by airflow distortion and are made close to the water surface, where gas gradients are largest. Flux measurements were complemented by near-surface hydrographic measurements to elucidate physical factors influencing DMS emission. Individual DMS fluxes derived by EC showed significant scatter and, at times, consistent departures from the Coupled Ocean–Atmosphere Response Experiment gas transfer algorithm (COAREG. A direct comparison between the two flux methods was carried out to separate instrumental effects from environmental effects and showed good agreement with a regression slope of 0.96 (r2 = 0.89. A period of abnormal downward atmospheric heat flux enhanced near-surface ocean stratification and reduced turbulent exchange, during which GF and EC transfer velocities showed good agreement but modelled COAREG values were significantly higher. The transfer velocity derived from near-surface ocean turbulence measurements on a spar buoy compared well with the COAREG model in general but showed less variation. This first direct comparison between EC and GF fluxes of DMS provides confidence in compilation of flux estimates from both techniques, as well as in the stable periods when the observations are not well predicted by the COAREG

Gradient flux measurements of sea-air DMS transfer during the Surface Ocean Aerosol Production (SOAP) experiment

Science.gov (United States)

Smith, Murray J.; Walker, Carolyn F.; Bell, Thomas G.; Harvey, Mike J.; Saltzman, Eric S.; Law, Cliff S.

2018-04-01

Direct measurements of marine dimethylsulfide (DMS) fluxes are sparse, particularly in the Southern Ocean. The Surface Ocean Aerosol Production (SOAP) voyage in February-March 2012 examined the distribution and flux of DMS in a biologically active frontal system in the southwest Pacific Ocean. Three distinct phytoplankton blooms were studied with oceanic DMS concentrations as high as 25 nmol L-1. Measurements of DMS fluxes were made using two independent methods: the eddy covariance (EC) technique using atmospheric pressure chemical ionization-mass spectrometry (API-CIMS) and the gradient flux (GF) technique from an autonomous catamaran platform. Catamaran flux measurements are relatively unaffected by airflow distortion and are made close to the water surface, where gas gradients are largest. Flux measurements were complemented by near-surface hydrographic measurements to elucidate physical factors influencing DMS emission. Individual DMS fluxes derived by EC showed significant scatter and, at times, consistent departures from the Coupled Ocean-Atmosphere Response Experiment gas transfer algorithm (COAREG). A direct comparison between the two flux methods was carried out to separate instrumental effects from environmental effects and showed good agreement with a regression slope of 0.96 (r2 = 0.89). A period of abnormal downward atmospheric heat flux enhanced near-surface ocean stratification and reduced turbulent exchange, during which GF and EC transfer velocities showed good agreement but modelled COAREG values were significantly higher. The transfer velocity derived from near-surface ocean turbulence measurements on a spar buoy compared well with the COAREG model in general but showed less variation. This first direct comparison between EC and GF fluxes of DMS provides confidence in compilation of flux estimates from both techniques, as well as in the stable periods when the observations are not well predicted by the COAREG model.

Multipurpose stabilization of the advanced marine surface crafts

Directory of Open Access Journals (Sweden)

Sevostyanov Ruslan A.

2016-01-01

Full Text Available Advanced marine surface crafts, such as SWATHs, catamarans or hovercrafts become more and more popular for a great range of various tasks. They usually operate at much higher speed than conventional ships. Moreover, in the open sea there are a lot of requirements and restrictions concerning the quality of such crafts’ dynamics, especially in case of the wind or waves. This paper considers application of the control law with a special multipurpose structure for autopilot design for amphibious air cushion vehicles. Such control law allows to decompose the autopilot task into simpler optimization subtasks. Efficiency of this approach is shown in the task of stabilizing yaw angle of the air cushion vehicle in the different weather conditions.

Note: Development of a small maglev-type antirolling system.

Science.gov (United States)

Park, Cheol Hoon; Park, Hee Chang; Cho, Han Wook; Moon, Seok Jun; Chung, Tae Young

2010-05-01

Various passive and/or active antirolling devices have been used for suppressing the rolling motion of ships in the ocean. In this study, a maglev-type active mass driver (AMD) is developed for controlling the rolling motion of a shiplike structure. No friction is generated during the motion of this maglev-type AMD, as the moving mass is floated by the magnetic levitation force and displaced by the propulsion force generated by the linear motor. For verifying the feasibility of the proposed method, a small AMD having a moving mass of approximately 4.0 kg is constructed and used in a small-scale model of a catamaran. This paper presents the detailed design procedures and obtained experimental results. Our results show that the developed maglev-type AMD has the potential for use in controlling the rolling motion of ships and other oceanographic vessels.

Improving the Efficiency of a High Speed Catamaran Through the Replacement of the Propulsion System

Directory of Open Access Journals (Sweden)

German de Melo Rodriguez

2015-12-01

Full Text Available The high speed vessels are primarily designed for short distances services as public transport of passengers and vehicles. The range of high speed, according to the Code of high-speed vessels begins at 20 knots, which depends on the cruise speed you desire for your vessel; you will have to use the most appropriate type of propellant. In general, in the past 20 years, they have been building high-speed vessels with speeds above 33 knots, which meant installing water jet propellants coupled to powerful engines and therefore of high consumption of fuel, increasing operating costs and causing increased air pollution. Although the prices of fuel have been reduced to half, due to the sharp fall in oil prices, the consumption of fuel and the air pollution remains high at these speeds and powers used, in addition to that the reduction of the time spent on each trip is not excessive, mainly in short routes that are less than an hour . This article is about adapting a ship of high-speed service, with a maximum speed in tests of 34 knots and to reduce its operating costs (fuel, maintenance, etc. and make it economically viable; before the transformation, this vessel was operating with a service speed of 22 knots, and with a consumption per mile of 135 litters of MGO. The transformation process has consisted by: – Replacement of the two original water jet with four shaft lines with fix pitch propeller. – Replacement of the two original main engines (2 x 6500 kW = 13000 kW by four engines (4 x 1380kW = 5.520 kW. – Changing the underwater hull shape to fit the new propellers and maximize its efficiency. – Relocation of auxiliary engines, to achieve the most efficient trim. – Installation of two lateral propellers to improve maneuverability and shorten the total time of journey. After the reform and the return to service of the vessel with a service speed of over 22 knots, it has been verified that the consumption per mile is of 45 litters MGO, representing a reduction of 65% of consumption and even more reduction of emissions as the new engines comply with the latest regulations.

Damage Stability Assessment of an HSC after Grounding

DEFF Research Database (Denmark)

Ravn, Erik Sonne; Simonsen, Bo Cerup; Baatrup, Jan

2000-01-01

Currently a substantial effort is done within the International Maritime Organisation (IMO) on revision of the High Speed Craft (HSC) Code. A main issue is the extent of bottom damage and raking damage due to grounding on hard rocks and the corresponding requirements to the damage stability...... of the vessel. It has been found that high-speed craft can experience a damage length up to 100% of the ship length. It has, however, also been argued that the damage stability requirements should reflect the size and probability of the damage with a reduction of the demand for the largest damages.......In the present paper a detailed grounding and damage stability analysis is carried out for two specific HSC, a mono-hull (86 m) and a catamaran (69 m). First various grounding scenarios are considered with different values of the forward speed and ground geometry. The results indicate that 100% bottom damage...

Wind turbine operated sailboat

Energy Technology Data Exchange (ETDEWEB)

Hall, R.

1990-07-31

A wind powered boat is disclosed which incorporates a vertical axis rotary turbine. A shaft portion extends downwardly from the turbine to a water pump, with the boat being provided with a forwardly opening inlet and a rearwardly opening outlet from the water pump. When rotating, the turbine operates the pump by the shaft to draw in water through the inlet, thereby creating a low pressure area in front of the boat, and to force the water out through the outlet for propelling the boat. In a preferred embodiment, the boat has a catamaran construction or is a large ocean going vessel with enough width to provide a buffer to either side of the turbine, and the turbine is the Darrieus rotor type. The pump is a standard centrifugal type of pump. A self adjusting braking device for the turbine is also disclosed, which prevents over-rotation and is also capable of storing heat energy generated during braking. 4 figs.

High Performance Marine Vessels

CERN Document Server

Yun, Liang

2012-01-01

High Performance Marine Vessels (HPMVs) range from the Fast Ferries to the latest high speed Navy Craft, including competition power boats and hydroplanes, hydrofoils, hovercraft, catamarans and other multi-hull craft. High Performance Marine Vessels covers the main concepts of HPMVs and discusses historical background, design features, services that have been successful and not so successful, and some sample data of the range of HPMVs to date. Included is a comparison of all HPMVs craft and the differences between them and descriptions of performance (hydrodynamics and aerodynamics). Readers will find a comprehensive overview of the design, development and building of HPMVs. In summary, this book: Focuses on technology at the aero-marine interface Covers the full range of high performance marine vessel concepts Explains the historical development of various HPMVs Discusses ferries, racing and pleasure craft, as well as utility and military missions High Performance Marine Vessels is an ideal book for student...

Yachting Club

CERN Multimedia

Yachting Club

2012-01-01

  Sailing course lottery Potential learners still have a couple of days to sign up to the Lottery for places in this season’s sailing courses. Yes, it is already quite heavily oversubscribed - as every year: we must run good courses! - but the draw is completely fair so you stand as good a chance as anyone else. Among questions we have been asked is which course is least oversubscribed - and might therefore offer a better chance of a place? Probably Surprise, since you ask, but then that is also one of the most demanding, both in terms of requisite keys you already need even to sign up in the Lottery and also likelihood of passing the test. Well, one was our most expensive boat purchase ever, and she is a boat that revels in being sailed well (even while being forgiving of the rest of us). The picture alongside is a loosely connected explanation to another question we get: how did catamaran Meerkat get named? We convinced ourselves that Meerkats are friendly, sociable, fast, intell...

YACHTING CLUB

CERN Document Server

YACHTING CLUB

2010-01-01

INTERNAL RAGATTE - BEST EVER ! If you missed Internal Regatta III on Sunday 11 July, you missed one of the best we can recall! The winds were about perfect, fairly stable Bf 2 with periodic gusts higher and the resulting capsizes to keep crews concentrating. It was extremely hot but we ran the usual three heats for keelboats and a record four for dinghies, catamarans - where there was another record, surely: a total of 11 boats in that class, of which three privately owned by members. And a final record: we calculate five boats were competing in their first-ever regatta. Results on the webpage. Surprisingly for those who remember regattas of a couple of years back, only three keelboats competed, so there would have been plenty of scope for less experienced members to come along regardless and probably find themselves a place. It is also noteworthy that the keelboat winner was Andrea Messina with an - ummm, may I say - less experienced crew himself! We hope this win bodes well for his forthcoming Transl&am...

Summary of the papers of the 95th Meeting of the West Japan Society of Naval Architects. Joint meeting of three shipbuilding societies in fall, fiscal 1997; Seibu Zosenkai dai 95 kai reikai ronbun gaiko. 1997 nendo shuki zosen sangakkai rengo koenkai

Energy Technology Data Exchange (ETDEWEB)

NONE

1997-10-01

The paper summarized the papers on the following: estimation of the propulsion performance by the surface vortex lattice method using model ship flow field data; wave-making resistance calculation and performance estimation by the Rankine source method; calculation method of wave-making resistance of Catamaran and solution method of the hydrofoil problem using the convenient panel method; study of estimation of hydrodynamic forces acting on ship in maneuvering motion; study of the combined plant using generator use diesel exhaust heat; mathematical structure of the ocean container transport system; developmental OTEC plants in Indonesia. In relation to structural dynamics/strength problems, reports were made on the hull longitudinal strength theory, FEM modeling in analyses of buckling/plasticity collapse of deflection panels, etc. Further reported were a consideration of the use classification of hull use steel sheets considering fracture toughness, and changes of aspect ratios of small surface cracks emanating from a toe of corner boxing. Concerning ocean structures, there are experimental studies on vibration in water of a semi-spherical shell fixed in water, and a behavior of huge floating structures in regular waves

92nd Meeting of West Japan Society of Naval Architects. Summary of papers; Seibu zosenkai dai 92 kai reikai. Ronbun kogai

Energy Technology Data Exchange (ETDEWEB)

NONE

1996-04-10

The 92nd Meeting of West Japan Society of Naval Architects was held at Shimonoseki city on May 9 and 10, 1996, and 27 papers were made public. As for hydrodynamic force, the following were reported: Hydrodynamic interference between hull and submerged foils; An experimental research on maneuvering hydrodynamic force interference coefficients; A research on the method to estimate maneuvering hydrodynamic force at swirl motion; An experimental research on the method to estimate hydrodynamic force added to floating offshore structures, etc. As to the high-speed hydrofoil catamaran, Cabin connected to hull by spring and its riding comfort in waves, and Cabin connected to hull and vibration response. Relating to fundamental experiments, An experiment on vibration in water of the cylinder shell fixed in water; An research on fracture behavior of rectangular waves under water pressure; Buckling of the continuous stiffened plate under in-plane compressive loads; An research on plasticity decay behavior, etc. In addition, The aesthetics of ship design and the dynamic symmetry; Spilt oil pollution preventive measures and effects of the ocean preservation, etc.

CERN Yachting club

CERN Document Server

CERN Yachting club

2015-01-01

Surely among the most active sports clubs within CERN, the Yachting Club has had a steadily increasing membership over a decade; it is now around 350 but new members are always welcome, especially now at the beginning of a season. Indeed, with the Lottery for places in courses which are one of our highlights, membership has jumped since mid-March. The Lottery is always heavily oversubscribed, which we like to think represents its good reputation for quality of teaching and good fun at the same time. Now those lucky new students are in contact with their teachers, will be buying wetsuits in some cases (dinghy and catamaran courses), joining us for the launch of the fleet (see calendar on website at http://yachting.web.cern.ch/yachting/ycc_home.html ) and  – in many cases – learning sailing as complete beginners. Those Lottery-unlucky can still plan a fun season, with our Thursday Practice evenings, where we can almost always place everyone on a boat for an outing.   ...

YACHTING CLUB

CERN Multimedia

Yachting Club

2010-01-01

TRAVERSEE DU LAC MEETS BOL D’OR It is not entire coincidence that your ever-attentive YCC Committee schedules our Traversée du Lac (dinghies, catamarans, windsurfs - although admittedly not many of the latter these last few seasons) for the same weekend as the rather larger-scale Bol d’Or: it enables our intrepid crews to practise their priority rules as Dona Bertarelli sweeps past with LadyCat and gives you something to watch should the wind drop momentarily ... The rest is history, as we say and your scribe will not repeat here the results, either of the Traversée or of the Bol - go find them on our respective Webs! But many thanks to John and Sarah Fullerton for organising this event and to Wolfgang Adam for ably skippering our new Q-boat. And a gentle reminder to us all, please, that we are fairly short of volunteers on all fronts: not merely routine maintenance, remembering to clean the boat you enjoy from time to time but also - urgently - Q-boat skippers (she&...

MobiCat - a solar-electrical passenger boat; MobiCat solar-elektrisches Passagierschiff

Energy Technology Data Exchange (ETDEWEB)

Minder, R.

2003-07-01

This final report for the Swiss Federal Office of Energy presents the results of the 'MobiCat' project which included the design, construction and operation of a solar-electric powered passenger ship for inland waterways. The vessel is of a catamaran with a length of 33 m and a width of 11 m. The electrical energy is produced by a 20 kW{sub p} array of photovoltaic panels and stored in two 480 V lead-acid battery blocks rated at 240 Ah each. The ship is powered by two 81 kW industrial AC drives. With a passenger capacity of 150 persons MobiCat is the largest solar-powered ship world-wide. The report discusses the generally positive operational experience and the wide interest both by the public and the media that the project has attracted. The MobiCat has become the most popular charter ship on the lake of Biel/Bienne in Switzerland. The author states that the ultimate goals of the project - to demonstrate the feasibility of large solar-powered passenger ships and to present new sustainable mobility solutions on inland waterways - have been fully reached.

High Resolution Marine Magnetic Survey of Shallow Water Littoral Area

Science.gov (United States)

Ginzburg, Boris; Cohen, Tsuriel Ram; Zafrir, Hovav; Alimi, Roger; Salomonski, Nizan; Sharvit, Jacob

2007-01-01

The purpose of this paper is to present a system developed for detection and accurate mapping of ferro-metallic objects buried below the seabed in shallow waters. The system comprises a precise magnetic gradiometer and navigation subsystem, both installed on a non-magnetic catamaran towed by a low-magnetic interfering boat. In addition we present the results of a marine survey of a near-shore area in the vicinity of Atlit, a town situated on the Mediterranean coast of Israel, about 15 km south of Haifa. The primary purpose of the survey was to search for a Harvard airplane that crashed into the sea in 1960. A magnetic map of the survey area (3.5 km2 on a 0.5 m grid) was created revealing the anomalies at sub-meter accuracy. For each investigated target location a corresponding ferro-metallic item was dug out, one of which turned to be very similar to a part of the crashed airplane. The accuracy of location was confirmed by matching the position of the actual dug artifacts with the magnetic map within a range of ± 1 m, in a water depth of 9 m. PMID:28903191

Controlling air pollution from passenger ferries: cost-effectiveness of seven technological options.

Science.gov (United States)

Farrell, Alexander E; Corbett, James J; Winebrake, James J

2002-12-01

Continued interest in improving air quality in the United States along with renewed interest in the expansion of urban passenger ferry service has created concern about air pollution from ferry vessels. This paper presents a methodology for estimating the air pollution emissions from passenger ferries and the costs of emissions control strategies. The methodology is used to estimate the emissions and costs of retrofitting or re-powering ferries with seven technological options (combinations of propulsion and emission control systems) onto three vessels currently in service in San Francisco Bay. The technologies include improved engine design, cleaner fuels (including natural gas), and exhaust gas cleanup devices. The three vessels span a range of ages and technologies, from a 25-year-old monohull to a modern, high-speed catamaran built only four years ago. By looking at a range of technologies, vessel designs, and service conditions, a sense of the broader implications of controlling emissions from passenger ferries across a range of vessels and service profiles is provided. Tier 2-certified engines are the most cost-effective choice, but all options are cost-effective relative to other emission control strategies already in place in the transportation system.

High Resolution Marine Magnetic Survey of Shallow Water Littoral Area

Directory of Open Access Journals (Sweden)

Jacob Sharvit

2007-09-01

Full Text Available The purpose of this paper is to present a system developed for detection andaccurate mapping of ferro-metallic objects buried below the seabed in shallow waters. Thesystem comprises a precise magnetic gradiometer and navigation subsystem, both installedon a non-magnetic catamaran towed by a low-magnetic interfering boat. In addition wepresent the results of a marine survey of a near-shore area in the vicinity of Atlit, a townsituated on the Mediterranean coast of Israel, about 15 km south of Haifa. The primarypurpose of the survey was to search for a Harvard airplane that crashed into the sea in 1960.A magnetic map of the survey area (3.5 km2 on a 0.5 m grid was created revealing theanomalies at sub-meter accuracy. For each investigated target location a correspondingferro-metallic item was dug out, one of which turned to be very similar to a part of thecrashed airplane. The accuracy of location was confirmed by matching the position of theactual dug artifacts with the magnetic map within a range of ± 1 m, in a water depth of 9 m.

New oil skimmer from shell

Energy Technology Data Exchange (ETDEWEB)

1978-06-01

Under a program initiated by the US Coast Guard (USCG), Shell Development Co. has developed the Zero-Relative Velocity Skimmer (ZRVS) (Abstract No. 24-30285) which can recover spilled oil in currents up to eight knots. Tests of a full-scale mockup of the system gave excellent results up to the test limit of eight knots and in waves up to 2 ft high. Conventional oil skimmers slow down the floating oil relative to the water so that it can be contained and collected. But when the relative velocity of water and skimmer exceeds 1 to 2 knots, turbulence caused by the skimmer's surface piercing equipment leads to oil escaping. The ZRVS combats this by laying twin floating, adsorbent belts on the surface so they move at the same speed as the water and oil relative to the skimmer. With no relative velocity between them, turbulence is removed, allowing the skimmer to operate effectively in fast currents. The skimmer is a 41 ft catamaran, built in three sections so it can be transported in two aircraft and assembled at the port nearest the spill. The first prototype is due to be completed at the USCG shipyard in the summer of 1978.

Estimation of performance of a high-speed boat by using the Rankine source method; Kosokutei no rankinsosuho ni yoru seino suitei ni tsuite

Energy Technology Data Exchange (ETDEWEB)

Eguchi, T [Mitsui Engineering and Shipbuilding Co. Ltd., Tokyo (Japan)

1997-10-01

This paper describes estimation of performance of a high-speed boat by using the Rankine source method. An orthogonal coordinate system is considered, which uses the center of a hull as the zero point, and is made dimensionless by using the hull length. The catamaran boat or the single hull boat being the subject of the discussion is supposed to have a transom stern, and to be sailing at a constant speed in the -X direction. A governing equation and a border condition were formulated using disturbance speed potential and X-direction speed differentiation. An inverse specular image was employed as a specular image system upon considering attitude change in the high-speed boat. As to the division of hull surface, the portions protruded above the static water surface were cut off from among the panel data of boat CAD. Considering a high speed condition in which the water surface is completely separated at the transom section, the water level at the transom section was supposed to be at the same height as at the rear end of the hull. Blow-out intensity at the water surface was derived in such a way that a CAD panel of the rear end of the hull is searched and wave height agrees with the height of the transom in the Z direction. A resistance curve may be obtained easily by using a personal computer. 4 refs., 8 figs.

Retrospective assessment of macrophytic communities in southern Lake Garda (Italy from in situ and MIVIS (Multispectral Infrared and Visible Imaging Spectrometer data

Directory of Open Access Journals (Sweden)

Claudia Giardino

2012-01-01

Full Text Available In situ and hyperspectral MIVIS (Multispectral Infrared and Visible Imaging Spectrometer images acquired over a period of 13 years are used to assess changes in macrophyte colonization patterns in the coastal zones of the Sirmione Peninsula in the southern part of Lake Garda (Italy. In situ data (abundance, cover density and diversity of macrophyte communities and MIVIS-derived maps of colonized substrates are analyzed by considering the variability of the main hydrological and physicochemical variables in order to indicate the main factors that explain the spatiotemporal variability of macrophyte communities. The results show a considerable modification in terms of macrophyte structural complexity and colonized areas. Almost 98% of macrophyte meadows (in particular communities with a density of over 70% are lost and subsequently replaced by moderate to extremely rare communities with density from 10% to 40%. Well-established submerged macrophytes are replaced by de-structured communities characterized by moderate to scarce density: on average lower than 30%. The study indicates that macrophyte distribution along the littoral zone of the Sirmione Peninsula is certainly linked to water transparency and water level fluctuation. The results also indicate that the worsening of eutrophication may be associated with the gradual disappearance of macrophyte meadows, but may also be accelerated by herbivorous aquatic birds grazing there. Lastly, the increasing frequency and number of catamaran tours could be considered a threat for the stability of these valuable communities.

Archive of side scan sonar and swath bathymetry data collected during USGS cruise 10CCT01 offshore of Cat Island, Gulf Islands National Seashore, Mississippi, March 2010

Science.gov (United States)

DeWitt, Nancy T.; Flocks, James G.; Pfeiffer, William R.; Wiese, Dana S.

2010-01-01

activity for that project in that calendar year. Refer to http://walrus.wr.usgs.gov/infobank/programs/html/definition/activity.html for a detailed description of the method used to assign the field activity ID. Data were collected using a 26-foot (ft) Glacier Bay Catamaran. Side scan sonar and interferometric swath bathymetry data were collected simultaneously along the tracklines. The side scan sonar towfish was towed off the port side just slightly behind the vessel, close to the seafloor. The interferometric swath transducer was sled-mounted on a rail attached between the catamaran hulls. During the survey the sled is secured into position. Navigation was acquired with a CodaOctopus Octopus F190 Precision Attitude and Positioning System and differentially corrected with OmniSTAR. See the digital FACS equipment log for details about the acquisition equipment used. Both raw datasets were stored digitally and processed using CARIS HIPS and SIPS software at the USGS St. Petersburg Coastal and Marine Science Center. For more information on processing refer to the Equipment and Processing page. Post-processing of the swath dataset revealed a motion artifact that is attributed to movement of the pole that the swath transducers are attached to in relation to the boat. The survey took place in the winter months, in which strong winds and rough waves contributed to a reduction in data quality. The rough seas contributed to both the movement of the pole and the very high noise base seen in the raw amplitude data of the side scan sonar. Chirp data were also collected during this survey and are archived separately.

Preparing for the America's Cup: A technological and a human challenge

KAUST Repository

Fischer, Martin

2017-01-17

The America\\'s Cup is the pinnacle event in sailing and it is the oldest sports trophy in the world. The trophy was originally awarded in 1851 for a race around the Isle of Wight, which was won by the schooner ﾑAmericaﾒ. It was subsequently renamed after the yacht and was donated to the New York Yacht Club under the terms of the Deed of Gift, which made the Cup available for perpetual international competition. The 35th America\\'s Cup will be held in May / June 2017 in Bermuda. The races will be sailed in 50-ft foiling catamarans. Instead of a main sail the boats feature a rigid wing. These boats are capable of sailing 3 times the wind speed, with top speeds reaching 45 knots. The lecture describes the technological and human endeavor to develop and prepare the boat and the crew. Developing an America\\'s Cup boat is a multidisciplinary effort. Excellence is required in such different fields as aerodynamics, hydrodynamics, structural analysis, advanced composite engineering and building, design of mechanical control systems, hydraulics, electronics and flight control, to name the most important ones. Since automatic control systems (autopilots) are forbidden in the America\\'s Cup rules there is a strong two-way feedback between sailing practicalities and the technological choices being made. Combine this with the management of a very tight build schedule for hulls, beams, foils, rudders and the wing and you get an idea what it means to prepare for the America\\'s Cup.

Zapata Ugland

Energy Technology Data Exchange (ETDEWEB)

1974-05-01

The Zapata SS-3000, the largest semisubmersible built to data in the US, was recently completed by Bethlehem Steel's Beaumont Yard (Tex.) for the Ugland group of companies in Grimstad, Norway. The rig will start drilling east of Shetland for Total under a 12-y bareboat charter by the joint-venture Zapata Ugland Drilling Inc. (70% Zapata, 30% Ugland). The unit is designed with catamaran lower hulls and 6 stability columns supporting a watertight upper hull. The lower hulls have a sea-barge configuration with faired bows for optimum heave-dampening action and propulsion. The upper hull is designed to minimize the amount of exposed machinery and storage on the upper deck. The unit is designed to drill in waves of up to 40 to 50 ft and remain moored in waves of up to 100 ft. Self-propelled at speeds of up to 9 knots, the rig has a mooring system designed for 1000-ft water depths and a deckload capacity of 3000 tons to allow long-period operation without resupply. The special storm-shield mooring system was designed from extensive computer analyses based on model test data, theoretical evaluation, and mooring-system operational data. The system consists of a conventional 8-line spread of 3500-ft lengths of 3-in. chains and two 3500-ft storm lines, with each leading out to a high-holding-capacity 40,000-lb Baldt Moorfast anchor. The storm-shield system is designed to withstand storms, wave actions, and associated storm currents from 100-knot sustained winds.

The optimal access system for future far-offshore wind farms

Energy Technology Data Exchange (ETDEWEB)

Obdam, T.S.; Rademakers, L.W.M.M.; Savenije, L.B. [ECN Wind Energy, Petten (Netherlands)

2013-12-15

Operation and maintenance (O and M) of offshore wind turbines is one of the main cost drivers of offshore wind energy. One of the aspects critical for an efficient and cost-effective O and M strategy is the selection of the access system which is used to transfer technicians and, optionally, small spare parts. Currently, most offshore wind farms are located close to shore, and their size is relatively small. For these farms the typical access system consists of catamaran-like workboats, which are used to transfer both technicians and small spare parts. As wind farms move further offshore this O and M concept might no longer be cost-effective. Currently, different alternative O and M concepts are being considered for the future far-offshore sites. In this paper an extensive and holistic comparison of different O and M concepts including different access system solutions is presented. This analysis has been performed using the OMCECalculator, ECN's software for advanced O and M cost modelling. Different sites have been considered, which are typical for the future offshore wind farms that will be commissioned during the next five years. The results of the performed analyses indicate that when moving further offshore harbour-based O and M strategies are no longer economical, even when helicopters are added to the mix. Looking at farm-based O and M concepts a supply vessel with a compensated access gangway offers great potential. However, the calculations also indicate that its ability to transfer small spare parts, in addition to technicians, is crucial.

The history and source of particulate 137Cs and 239,240Pu deposition in sediments of the Ob River Delta, Siberia

International Nuclear Information System (INIS)

Sayles, F.L.; Livingston, H.D.; Panteleyev, G.P.

1997-01-01

This paper presents the first results of a project designed to examine the transfer of particle-associated artificial radionuclides down the Ob River in Siberia to its delta over the past 5 decades. The main sources include fallout from atmospheric nuclear weapons tests and weapons complexes and test sites of the Former Soviet Union in or near the Ob watershed. The approach is to measure the accumulation of the radionuclides in undisturbed delta sediments - obtaining a record of their deposition over time. These records were found in sediments of shallow lakes apart from, and connected to, the main channel. Sediment cores were collected in the summer of 1994 using a shallow draft catamaran to reach these lakes from a support ship in the main channel. Measurements are presented on the depth distributions of 137 Cs and Pu isotopes and their inventories in a series of dated sediment cores - including one from a location in the Taz Estuary (which does not receive Ob River sediments). Sediment dating was carried out using the excess 210 Pb technique. The results obtained are compared with known information on the temporal history of releases from the various sources and characteristics of the isotopic composition of the sources. The results show that good records of radionuclide deposition indicate that the major fraction of 137 Cs and Pu isotopes deposited in these delta sediments comes from atmospheric nuclear weapons test fallout - both delivered directly from the atmosphere and from downstream transport of watershed sediments. No more than 25% of the observed inventories could be derived from other sources

Feasibility of using Big Area Additive Manufacturing to Directly Manufacture Boat Molds

Energy Technology Data Exchange (ETDEWEB)

Post, Brian K. [ORNL; Chesser, Phillip C. [ORNL; Lind, Randall F. [ORNL; Sallas, Matthew R. [ORNL; Love, Lonnie J. [ORNL

2018-01-01

The goal of this project was to explore the feasibility of using Big Area Additive Manufacturing (BAAM) to directly manufacture a boat mold without the need for coatings. All prior tooling projects with BAAM required the use to thick coatings to overcome the surface finish limitations of the BAAM process. While the BAAM process significantly lowers the cost of building the mold, the high cost element rapidly became the coatings (cost of the material, labor on coating, and finishing). As an example, the time and cost to manufacture the molds for the Wind Turbine project with TPI Composites Inc. and the molds for the submarine project with Carderock Naval Warfare Systems was a fraction of the time and cost of the coatings. For this project, a catamaran boat hull mold was designed, manufactured, and assembled with an additional 0.15” thickness of material on all mold surfaces. After printing, the mold was immediately machined and assembled. Alliance MG, LLC (AMG), the industry partner of this project, experimented with mold release agents on the carbon-fiber reinforced acrylonitrile butadiene styrene (CF ABS) to verify that the material can be directly used as a mold (rather than needing a coating). In addition, for large molds (such as the wind turbine mold with TPI Composites Inc.), the mold only provided the target surface. A steel subframe had to be manufactured to provide structural integrity. If successful, this will significantly reduce the time and cost necessary for manufacturing large resin infusion molds using the BAAM process.

METHODOLOGY OF THE HYBRID PROPULSION SYSTEM (DMP & DEP FOR TRIMARAN TYPE FAST PATROL BOAT

Directory of Open Access Journals (Sweden)

Aulia Widyandari

2012-04-01

Full Text Available There are lot of research done to develop a patrol boat, from the modification of hull model until propulsion system equipment. For example the model ship type AMV (Advanced Marine Vehicle was developed starting from the Catamaran, Trimaran and  Pentamaran model. Everything is aimed at obtaining the ship design that has the speed and stability. In addition to achieving high-speed vessel must be equipped with propulsion (Main Power is great, that means the main engine dimensions, auxiliary equipments and fuel tanks is too large. Many Limitations of space on the ship's engine room trimaran vessel is the main obstacle in designing propulsion system. Beside that Patrol boat should have many missions speed, so propulsion system should be designed at that conditions.   Hybrid propulsion is a combination of Diesel Mechanical Propulsion (DMP with Diesel Electric Propulsion (DEP. DMP system is connected directly to the propeller shaft (or through a reduction-gear. DMP has provide more efficiency rate of 95%. While DEP is only able to provide efficiency by 85% - 89% is slightly lower than DMP, but the DEP offers many advantages such as simplicity and suitability in the rotational speed settings, control systems, engine power production Redundancy, Flexibility in the design of equipments layout in engine rooms, noise, vibration and fuel consumption efficiency which affects the lower pollution.   Design of Hybrid Propulsion system can be satisfied and achieved the Power requirements and optimally at all speed condition of patrol boat. Therefore the author made using modeling Maxsurf-11.12 software and carried out various optimization of the choice of main engine, propeller and system conditions for fast patrol boat cruise. 

PERANCANGAN KAPAL UNTUK MENUNJANG KEGIATAN PARIWISATA DI WADUK JATILUHUR, PURWAKARTA

Directory of Open Access Journals (Sweden)

Parlindungan Manik

2012-02-01

Full Text Available Jatiluhur had the very big tourism potency so that it was required the supporting mean such as the tour ship which was better than the wooden ship. The research about the tour ship design having a catamaran hull form was expected to help the development of potencial tourism in Jatiluhur reservoir. In conducting this research, there were several research designs used those were the principle dimension, lines plan, general arrangement, hydrostatic analysis, stability analysis and ship motion analysis. Furthermore, it was used the selection of ship equipments and main engine which is based on result of motor power calculation appropriate for resistance against ship.  The result of this tourist ship design was in the form of hydrostatic analysis, general arrangement, the analysis of stability and ship motion. The resulth shown by the hydrostatic analysis was that the buoyancy located behind the midship as far as 0.469 m. In addition, the result of general arrangement indicated that this tour ship had enough rooms to store all the ship equipment and it was able to carry the passangers with the maximum capacity of twenty people. In a review analysis of stability, it was shown that the largest GZ value was 2,009 m in the ten condition in which it carried ten passangers on the left side with a consumable weight of 100%. This tour ship had a good ship motion in which the deck wetness was not occurred when the wave happened as 0,70 m with the wave heading of 90° having a value of amplitudo heave motion of 0,176 m, the pitchmotion of 1,04 °, and roll motion of 2,99 °.

Cross-Regional Assessment Of Coupling And Variability In Precipitation-Runoff Relationships

Science.gov (United States)

Carey, S. K.; Tetzlaff, D.; Soulsby, C.; Buttle, J. M.; Laudon, H.; McDonnell, J. J.; McGuire, K. J.; Seibert, J.; Shanley, J. B.

2011-12-01

The higher mid-latitudes of the northern hemisphere are particularly sensitive to change due to the important role the zero-degree isotherm plays in the phase of precipitation and intermediate storage as snow. An international inter-catchment comparison program North-Watch seeks to improve our understanding of the sensitivity of northern catchments to change by examining their hydrological and biogeochemical variability and response. The catchments are located in Sweden (Krycklan), Scotland (Mharcaidh, Girnock and Strontian), the United States (Sleepers River, Hubbard Brook and HJ Andrews) and Canada (Catamaran, Dorset and Wolf Creek). For this study, 8 catchments with 10 continuous years of daily precipitation and runoff data were selected to assess the seasonal coupling of rainfall and runoff and the memory effect of runoff events on the hydrograph at different time scales. To assess the coupling and synchroneity of precipitation, continuous wavelet transforms and wavelet coherence were used. Wavelet spectra identified the relative importance of both annual versus seasonal flows while wavelet coherence was applied to identify over different time scales along the 10-year window how well precipitation and runoff were coupled. For example, while on a given day, precipitation may be closely coupled to runoff, a wet year may not necessarily be a high runoff year in catchments with large storage. Assessing different averaging periods in the variation of daily flows highlights the importance of seasonality in runoff response and the relative influence of rain versus snowmelt on flow magnitude and variability. Wet catchments with limited seasonal precipitation variability (Strontian, Girnock) have precipitation signals more closely coupled with runoff, whereas dryer catchments dominated by snow (Wolf Creek, Krycklan) have strongly coupling only during freshet. Most catchments with highly seasonal precipitation show strong intermittent coupling during their wet season. At

A Coastal Bay Summer Breeze Study, Part 1: Results of the Quiberon 2006 Experimental Campaign

Science.gov (United States)

Mestayer, Patrice G.; Calmet, Isabelle; Herlédant, Olivier; Barré, Sophie; Piquet, Thibaud; Rosant, Jean-Michel

2018-04-01

The Quiberon 2006 experiment was launched to document the onset and development of land and sea breezes over a semi-circular coastal bay propitious to inshore sailing competitions. The measurements were taken during the 2 weeks of 16-28 June 2006. Micrometeorological variables were recorded at three shore sites around the bay using turbulence sensors on 10-30-m high masts, on four instrumented catamarans at selected sites within the bay, and at a fourth shore site with a Sodar. Synoptic data and local measurements are analyzed here from the point of view of both micrometeorologists and competition skippers, testing in particular the empirical rules of breeze veering and backing according to the wind direction with respect to the coastline orientation at the mesoscale (the quadrant theory). Our analysis focuses on the patterns of lower-altitude wind direction and speed around the bay and over the water basin, and the temporal variations during the periods of the breeze onset, establishment and thermal reinforcement. In offshore synoptic-flow conditions (quadrants 1 and 2), the clockwise rotation of the surface flow had a very large amplitude, reaching up to 360°. The breeze strength was negatively correlated to that of the synoptic wind speed. In conditions of onshore synoptic flow from the west (quadrant 3) at an angle to the mainland coast but perpendicular to the Quiberon peninsula, the rotation of the flow was backwards in the early morning and clockwise during the day with a moderate amplitude (40°-50°) around the synoptic wind direction. As the surface wind speed was much larger than the synoptic wind speed, such a case we have designated as a "synoptic breeze". The breeze onset was shown to fail several times under the influence of weak non-thermal events, e.g., the passage of an occluded front or clouds or an excess of convection. Finally, several local-scale influences of the complex coastal shape appeared in our measurements, e.g., wind fanning in the

Inter-comparison of hydro-climatic regimes across northern catchments: Synchronicity, resistance and resilience

Science.gov (United States)

Carey, S.K.; Tetzlaff, D.; Seibert, J.; Soulsby, C.; Buttle, J.; Laudon, H.; McDonnell, J.; McGuire, K.; Caissie, D.; Shanley, J.; Kennedy, M.; Devito, K.; Pomeroy, J.W.

2010-01-01

The higher mid-latitudes of the Northern Hemisphere are particularly sensitive to climate change as small differences in temperature determine frozen ground status, precipitation phase, and the magnitude and timing of snow accumulation and melt. An international inter-catchment comparison program, North-Watch, seeks to improve our understanding of the sensitivity of northern catchments to climate change by examining their hydrological and biogeochemical responses. The catchments are located in Sweden (Krycklan), Scotland (Mharcaidh, Girnock and Strontian), the United States (Sleepers River, Hubbard Brook and HJ Andrews) and Canada (Catamaran, Dorset and Wolf Creek). This briefing presents the initial stage of the North-Watch program, which focuses on how these catchments collect, store and release water and identify 'types' of hydro-climatic catchment response. At most sites, a 10-year data of daily precipitation, discharge and temperature were compiled and evaporation and storage were calculated. Inter-annual and seasonal patterns of hydrological processes were assessed via normalized fluxes and standard flow metrics. At the annual-scale, relations between temperature, precipitation and discharge were compared, highlighting the role of seasonality, wetness and snow/frozen ground. The seasonal pattern and synchronicity of fluxes at the monthly scale provided insight into system memory and the role of storage. We identified types of catchments that rapidly translate precipitation into runoff and others that more readily store water for delayed release. Synchronicity and variance of rainfall-runoff patterns were characterized by the coefficient of variation (cv) of monthly fluxes and correlation coefficients. Principal component analysis (PCA) revealed clustering among like catchments in terms of functioning, largely controlled by two components that (i) reflect temperature and precipitation gradients and the correlation of monthly precipitation and discharge and (ii

Development and Characteristics of a Mobile, Semi-Autonomous Floating Platform for in situ Lake Measurements

Science.gov (United States)

Barry, D.; Lemmin, U.; Le Dantec, N.; Zulliger, L.; Rusterholz, M.; Bolay, M.; Rossier, J.; Kangur, K.

2013-12-01

In the development of sustainable management strategies of lakes more insight into their physical, chemical and ecological dynamics is needed. Field data obtained from various types of sensors with adequate spatial and temporal sampling rate are essential to understand better the processes that govern fluxes and pathways of water masses and transported compounds, whether for model validation or for monitoring purposes. One advantage of unmanned platforms is that they limit the disturbances typically affecting the quality of data collected on small vessels, including perturbations caused by movements of onboard crew. We have developed a mobile, semi-autonomous floating platform with 8 h power autonomy using a 5 m long by 2.5 m wide catamaran. Our approach focused on modularity and high payload capacity in order to accommodate a large number of sensors both in terms of electronic (power and data) and mechanical constraints of integration. Software architecture and onboard electronics use National Instruments technology to simplify and standardize integration of sensors, actuators and communication. Piecewise-movable deck sections allow optimizing platform stability depending on the payload. The entire system is controlled by a remote computer located on an accompanying vessel and connected via a wireless link with a range of over 1 km. Real-time transmission of GPS-stamped measurements allows immediate modifications in the survey plan if needed. The displacement of the platform is semi-autonomous, with the options of either autopilot mode following a pre-planned course specified by waypoints or remote manual control from the accompanying vessel. Maintenance of permanent control over the platform displacement is required for safety reasons with respect to other users of the lake. Currently, the sensor payload comprises an array of fast temperature probes, a bottom-tracking ADCP and atmospheric sensors including a radiometer. A towed CTD with additional water quality

Advances in Shallow-Water, High-Resolution Seafloor Mapping: Integrating an Autonomous Surface Vessel (ASV) Into Nearshore Geophysical Studies

Science.gov (United States)

Denny, J. F.; O'Brien, T. F.; Bergeron, E.; Twichell, D.; Worley, C. R.; Danforth, W. W.; Andrews, B. A.; Irwin, B.

2006-12-01

, and sea bed morphology in water depths less than 5-m. The ASV is a catamaran-based platform, 10 feet in length, 4 feet in width, and approximately 260 lbs in weight. The vehicle is operated remotely through a wireless modem network enabling real-time monitoring of data acquisition. The ASV is navigated using RTK, and heave, pitch and roll are recorded with onboard motion sensors. Additional sensors, such as ADCPs, can also be housed within the vehicle. The ASV is able to operate in previously inaccessible areas, and will not only augment existing shallow-water research capabilities, but will also improve our understanding of the geologic controls to modern beach behavior and coastal evolution.

Conference on the Physics and Chemistry of Semiconductor Interfaces (26th) Held in the Catamaran Resort Hotel in Pacific Beach, San Diego, California on 17 January 1999 to 21 January 1999. Microelectronics and Nanometer Structures: Processing, Measurement, and Phenomena

Science.gov (United States)

2000-01-27

II-IV)1/2_ Type I m-OV- VDi /2 Type IT" One possibility which is denoted as type I materials is con- structed by replacing two group-Ill...71, 2048 (1992). I4A. L. Wachs, T. Miller, A. P. Shapiro, and T.-C. Chiang, Phys. Rev. B 35, 5514 (1987). 15T. Miller, T.-C. Hsieh, and T.-C

Immersive, hands-on, team-based geophysical education at the University of Texas Marine Geology and Geophysics Field Course

Science.gov (United States)

Saustrup, S.; Gulick, S. P.; Goff, J. A.; Davis, M. B.; Duncan, D.; Reece, R.

2013-12-01

The University of Texas Institute for Geophysics (UTIG), part of the Jackson School of Geosciences, annually offers a unique and intensive three-week marine geology and geophysics field course during the spring/summer semester intersession. Now entering its seventh year, the course transitions students from a classroom environment through real-world, hands-on field acquisition, on to team-oriented data interpretation, culminating in a professional presentation before academic and industry employer representatives. The course is available to graduate students and select upper-division undergraduates, preparing them for direct entry into the geoscience workforce or for further academic study. Geophysical techniques used include high-resolution multichannel seismic reflection, CHIRP sub-bottom profiling, multibeam bathymetry, sidescan sonar, sediment coring, grab sampling, data processing, and laboratory analysis of sediments. Industry-standard equipment, methods, software packages, and visualization techniques are used throughout the course, putting students ahead of many of their peers in this respect. The course begins with a 3-day classroom introduction to the field area geology, geophysical methods, and computing resources used. The class then travels to the Gulf Coast for a week of hands-on field and lab work aboard two research vessels: UTIG's 22-foot, aluminum hulled Lake Itasca; and NOAA's 82-foot high-speed catamaran R/V Manta. The smaller vessel handles primarily shallow, inshore targets using multibeam bathymetry, sidescan sonar, and grab sampling. The larger vessel is used both inshore and offshore for multichannel seismic, CHIRP profiling, multibeam bathymetry, gravity coring, and vibracoring. Field areas to date have included Galveston and Port Aransas, Texas, and Grand Isle, Louisiana, with further work in Grand Isle scheduled for 2014. In the field, students work in teams of three, participating in survey design, instrument set-up, field deployment

CHIRP survey of the submerged harbors of King Herod's Caesarea, offshore Israel - looking for evidence of ancient disasters

Science.gov (United States)

Austin, J. A.; Goodman-Tchernov, B.

2012-12-01

on the starboard flank of a ~8 m-long catamaran. Data acquisition was generally conducted from dawn to mid-day, when wind/wave conditions were most favorable. A dense (5-10 m average profile spacing) grid of profiles, both along-strike (spanning the entire harbor complex) and across-strike (from intermediate harbor to ~10-15 m of water), was acquired. Total track length is ~126 line-km. In certain places, multiple sub-bottom horizons can be traced and mapped; sub-seafloor penetrations up to ~ 4-5 m were occasionally achieved, particularly in deeper water. However, sub-bottom penetration is spatially variable in sand-prone sediments. Correlation difficulties relate both to uneven acoustic penetration and to the presence offshore of "kurkar" ridges, calcareous sandstone ridges paralleling the modern shoreline that represent now-submerged Pleistocene dune complexes. These ancient dunes can produce physical barriers that both alter the depositional regime as well as complicate the acoustic mapping task. Mapped horizons within the survey area will be shown, along with preliminary correlations to the stratigraphy described from previously cored sediments (e.g., interpreted "tsunamites").

Paradigm change in ocean studies: multi-platform observing and forecasting integrated approach in response to science and society needs

Science.gov (United States)

Tintoré, Joaquín

2017-04-01

-platform approach in ocean observation. Three examples from the integration capabilities of SOCIB facilities will be presented and discussed. First the quasi-continuous high frequency glider monitoring of the Ibiza Channel since 2011, an important biodiversity hot spot and a 'choke' point in the Western Mediterranean circulation, has allowed us to reveal a high frequency variability in the North-South exchanges, with very significant changes (0.8 - 0.9 Sv) occurring over periods of days to week of the same order as the previously known seasonal cycle. HF radar data and model results have also contributed more recently to better describe and understand the variability at small scales. Second, the Alborex/Perseus project multi-platform experiment (e.g., RV catamaran, 2 gliders, 25 drifters, 3 Argo type profilers & satellite data) that focused on submesoscale processes and ecosystem response and carried out in the Alborán Sea in May 2014. Glider results showed significant chlorophyll subduction in areas adjacent to the steep density front with patterns related to vertical motion. Initial dynamical interpretations will be presented. Third and final, I will discuss the key relevance of the data centre to guarantee data interoperability, quality control, availability and distribution for this new approach to ocean observation and forecasting to be really efficient in responding to key scientific state of the art priorities, enhancing technology development and responding to society needs.

System identification and the modeling of sailing yachts

Science.gov (United States)

Legursky, Katrina

yaw. Existing aerodynamic models for sailing yachts are unsuitable for control system design as they do not include a physical description of the sails' dynamic effect on the system. A new aerodynamic model is developed and validated using the full-scale sailing data which includes sail deflection as a control input to the system. The Maximum Likelihood Estimation (MLE) algorithm is used with non-linear simulation data to successfully estimate a set of hydrodynamic derivatives for a sailing yacht. It is shown that all sailing yacht models will contain a second order mode (referred to herein as Mode 1A.S or 4B.S) which is dependent upon trimmed roll angle. For the test yacht it is concluded that for this mode when the trimmed roll angle is, roll rate and roll angle are the dominant motion variables, and for surge velocity and yaw rate dominate. This second order mode is dynamically stable for . It transitions from stability in the higher values of to instability in the region defined by. These conclusions align with other work which has also found roll angle to be a driving factor in the dynamic behavior of a tall-ship (Johnson, Miles, Lasher, & Womack, 2009). It is also shown that all linear models also contain a first order mode, (referred to herein as Mode 3A.F or 1B.F), which lies very close to the origin of the complex plane indicating a long time constant. Measured models have indicated this mode can be stable or unstable. The eigenvector analysis reveals that the mode is stable if the surge contribution is 20%. The small set of maneuvers necessary for model identification, quick OSLS estimation method, and detailed modal analysis of estimated models outlined in this work are immediately applicable to existing autonomous mono-hull sailing yachts, and could readily be adapted for use with other wind-powered vessel configurations such as wing-sails, catamarans, and tri-marans. (Abstract shortened by UMI.)

Introduction

Science.gov (United States)

Narlikar, J. V.; Sathyaprakash, B. S.

2014-03-01

colleague Kumar (S.M.) Chitre and the younger one, Ajit Kembhavi, and the organizational infrastructure of TIFR. In particular, the then administrator dealing with scientific meetings, Parelkar enthusiastically joined me to set up the local boundary conditions in Goa. To get our priorities right, we first picked upon Hotel Mandovi in Panjim (Capital of Goa) as the nodal hotel for catering, accommodation, and arrangements of the academic sessions. We were expecting around 100 participants with 50% from abroad. Kamat, the Manager of Hotel Mandovi, promised all help including beds in nearby hotels to make up any shortfall. Regarding the quality of food, for which Hotel Mandovi was justly famous, its in-charge, Satish Prabhu took care of all our worries. Delegates may still recall the various Goan delicacies featured on the conference menus. Parelkar negotiated the basic deal with the hotels to extract the maximum benefits for the conference. But we were still rather vulnerable in lack of the local conditions. An unexpected helping hand came to make up for our lack of local knowledge. The amateur astronomer organization, called ''Friends of Astronomy in Goa'', led by their venerable President, Percival Noronha offered to run errands for us and play the role of local volunteer. Noronha had been associated with the state government of Goa, since the days when it was a Portuguese colony. His 'inside knowledge' came in useful, especially when he advised us to request the Chief Minister, Pratapsingh Rane to entertain the conference participants in the state catamaran. Somewhat hesitatingly, I wrote a request letter, and to my delightful surprise, the CM agreed. Indeed, the boat-ride followed by the CM's riverside banquet was the entertainment high point of the conference. The food, Goan drinks, and musical entertainment were well appreciated by the participants, and an uninitiated person might be forgiven for thinking that ICGC stood for ''International Conference on Goan