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In this similitude, the proportions are kept (the ratios between the various dimensions of the ship are identical). This is also the case with the block coefficient. Furthermore, the angles are a length ratio, so they are also identical to the original ones. The scale factors of the areas and volumes
450:
Those who have trained on both claim that scale models are complementary to electronic simulators. While manoeuvres with currents, waves, tugs, anchors, bank effects, etc. are reproduced more accurately on scale models, numerical simulators are more realistic when it comes to the bridge environment.
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First, manoeuvres on a model require the same pilot's orders as those on a real ship. The only difference is that they are executed five times faster on the model, so there is no time to discuss them (in fact, the rate of operation is such that the captain and helmsman swap roles every hour to avoid
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As far as the wind is concerned, it should be recalled that as the speed scale factor is 1 in 5, a wind of 10 knots on the lake is equivalent to a 50 knot squall in reality. Ripples on the surface of the water and the movement of leaves on the trees are therefore unreliable indicators. The wind and
406:
In conclusion, by choosing a scale of 1:25 for the lengths and by complying with Froude's law, the engineers at
Sogreah – Port Revel built models 25 times smaller, operating 5 times more slowly, but as the distances are 25 times less, things occur 5 times faster. The ships are 78 125 times less
228:
that can carry and be handled by at least one person on an open expanse of water. They must behave just like real ships, giving the shiphandler the same sensations. Physical conditions such as wind, currents, waves, water depths, channels and berths must be reproduced realistically.
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The model used for shiphandling training must not only resemble the original but also move in the same way as the original when subjected to similar forces. Consequently, the scale factor for the mass (M) and displacement is the same as that for the volumes, i.e.:
426:
Control panels show the usual information (engine speed, rudder angle, heading, log, wind speed and direction, shackles of chain lowered). This information is shown in real-life values to help the trainee forget as far as possible that he is on a scale
258:
The model has exactly the same geometric shape as the real ship. This means that all the length (L) dimensions of the real ship are divided by the same factor, the scale factor. The designers of Port Revel chose a scale (S) of 1:25, so:
308:
If the external forces on the model are in similitude, like the shapes, masses and inertia, the model's movement will be in similitude. It can thus be shown that the forces (F) must be at the same scale as the masses and weights, so:
420:
fatigue). This encourages responses to become intuitive but based upon a pre-assessed but flexible plan. What is a crisis on Day 1 of a manned model course becomes routine by Days 3+ which has to be a good definition of training.
437:
ship speeds displayed on the control panel are therefore very important for trainees. However, the lake is situated in a forest in a region with little wind, so that uncontrollable wind effects are minimised.
232:
Manned models are used for research (e.g. ship behaviour), engineering (e.g. port layout) and for training in shiphandling (e.g. maritime pilots, masters and officers). They are usually at 1:25 scale.
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While the models must be in correct similitude, this is not enough. Other factors can affect the correct reproduction of the manoeuvres, such as the field of vision, on-board equipment and wind.
244:(1810-1879) for its manned models. This means that gravity is considered to be preponderant over the other forces acting on the hull (viscosity, capillarity, cavitation, compressibility, etc.).
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The captain's position gives him a true field of vision from the bridge. He gives his orders to the helmsman, who is seated in front of him and operates the wheel and engine.
714:
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Many research workers, hydraulics specialists and engineers have used scale models for over a century, in particular in towing tanks. Manned models are small scale
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40 years' experience have shown that students quickly learn how to control the models just as they do the real ships that they are used to manoeuvring.
625:
Hydraulic laboratory techniques a guide for applying engineering knowledge to hydraulic studies based on 50 years of research and testing experience
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The ships are fitted with bow and stern thrusters and perfectly operational anchors. They behave like real ships from this point of view as well.
146:
35:
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Manned model exercises promote good situational and spatial awareness, a lack of which contributes to most accidents and incidents.
628:. A water resources technical publication. U.S. Dept. of the Interior, Water and Power Resources Service. 1980. pp. 37–56.
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Physical
Modelling in Coastal Engineering: Proceedings of an International Conference, Newark, Delaware, August 1981
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Tugs are under the captain's orders via remote control, and are handled by a real tug captain.
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Proceedings of the
International Conference on Coastlines, Structures and Breakwaters, 2005
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Worldwide, manned model schools have chosen to apply the similitude law of
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Getting New
Technologies Together: Studies in Making Sociotechnical Order
330:'s law, the velocity scale is the square root of the length scale, so:
225:
204:
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The different aspects of similitude may thus be defined as follows:
583:. NATO ASI Series E: Applied Sciences. Vol. 165. Springer.
559:
Physical Models and
Laboratory Techniques in Coastal Engineering
62:
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Coastal
Engineering: Processes, Theory and Design Practice
464:"Scale Effects in Physical Hydraulic Engineering Models"
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Emergency stop of a supertanker model with an escort tug
366:= sqrt(25) = 5 (times faster than in real life)
341:= sqrt(25) = 5 (times slower than in real life)
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266:= 25 (smaller, hence distance is 25 times less)
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649:. Thomas Telford. pp. 520–530, See p. 523.
138:but its sources remain unclear because it lacks
580:Recent Advances in Hydraulic Physical Modelling
663:
235:
503:Chadwick, A.; Reeve, D.; Fleming, C. (2004).
643:"7.7 Composite-berm rubble mound breakwater"
410:
347:Time is a distance (L) over speed (V), so:
50:Learn how and when to remove these messages
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187:Learn how and when to remove this message
169:Learn how and when to remove this message
99:Learn how and when to remove this message
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547:"8.6 Coastal sediment transport models"
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531:"8.4 Short-wave hydrodynamic models"
203:Captain's view from the bridge of a
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598:Dalrymple, Robert A., ed. (2018) .
539:"8.5 Long-wave hydrodynamic models"
13:
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680:. Walter de Gruyter. p. 22.
636:. 81-2613 – via HathiTrust.
31:This article has multiple issues.
219:
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83:by adding one in your own words.
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664:van der Meulen, Barend (1998).
523:"8.3 Theory of physical models"
372:As the power P = F x V, hence S
39:or discuss these issues on the
1:
468:Journal of Hydraulic Research
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270:are deduced from this, i.e.:
488:10.1080/00221686.2011.578914
7:
577:Martins, Rui, ed. (2012) .
236:Similitude of manned models
10:
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306:Similitude of forces (F):
507:. Taylor & Francis.
411:Similitude of manoeuvres
370:Similitude of power (P):
124:This article includes a
345:Similitude of time (T):
324:Similitude of speed(V):
288:Similitude of mass (M):
153:more precise citations.
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736:Hydraulic engineering
674:: §2 Technical Model"
556:Hughes, S.A. (1993).
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715:Marine-Marchande.net
562:. World Scientific.
256:Similitude of shape:
81:improve this article
549:. pp. 305–311.
480:2011JHydR..49..293H
462:Heller, V. (2011).
251:Physical similitude
672:Queen Elizabeth II
641:Melby, J. (2005).
326:In agreement with
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126:list of references
687:978-3-11-015630-0
620:"3. Model Design"
611:978-1-351-42464-6
590:978-94-009-2344-7
569:978-981-02-1541-5
525:. pp. 300–3.
514:978-0-415-26840-0
207:supertanker model
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320:= 25 = 15 625
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302:= 25 = 15 625
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284:= 25 = 15 625
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403:= 25 = 78 125
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145:Please help
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74:lead section
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33:Please help
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731:Model boats
407:powerful.
151:introducing
89:August 2024
725:Categories
703:Port Revel
668:T.Y. Draco
455:References
205:Port Revel
36:improve it
496:121563448
42:talk page
717:website
711:website
705:website
634:6984558
476:Bibcode
147:improve
79:Please
72:has no
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427:model.
384:, so:
328:Froude
226:models
709:AFCAN
670:with
492:S2CID
132:, or
682:ISBN
651:ISBN
630:OCLC
606:ISBN
585:ISBN
564:ISBN
509:ISBN
354:= S
337:= S
316:= S
484:doi
401:(L)
399:= S
397:(L)
395:x S
393:(L)
391:= S
389:(P)
382:(V)
380:x S
378:(F)
376:= S
374:(P)
364:(L)
362:= S
360:(V)
358:/ S
356:(L)
352:(T)
339:(L)
335:(V)
318:(M)
314:(F)
300:(L)
298:= S
296:(M)
282:(L)
275:(L)
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Text is available under the Creative Commons Attribution-ShareAlike License. Additional terms may apply.
