Maritime Hydraulics

Port Revel is a training centre for shiphandling on manned models which is located on a lake of about 13 acres (5 ha) that was remodelled in order to reproduce real sailing conditions. The centre is located near Grenoble (France).

At scale 1 in 25, the water area represents a navigable zone of about 3 by 2 nautical miles, allowing several models to sail at the same time at normal manoeuvring speeds. The lake has much permanent equipment and features.

The fleet of Port Revel is at present made up of eleven ships: six of these models represent at scale real oil tankers or bulk carriers ranging from 40 000 to 400 000 dwt. Two models are liquid natural gas (LNG) carriers: the “Ben Franklin” (120 000 m3) and the “Q-Max” (266 000 m3). Two models are container ships: one with a capacity of 4 400 TEU, the “Normandie” and one 8 500 TEU, the “Otello”. The latest model is a cruise ship, the “Voyager” with over 300 m length.

Several models are fitted with diesel motor and steam turbine, the Normandie can be controlled from the front deck like a car carrier and like a cruise ship, and the Ben Franklin has a Controllable Pitch Propeller, so that the fleet in fact reproduces 20 different vessels.

The models are fitted out with all the conventional features found on board a real ship. Obviously, the rudder and engine response times are respected. These are adjustable, as is the “power” of the engine, so as to reproduce the characteristics of turbine or diesel engine propulsion.

The crew of each model is made up of two students: one is “embarked” on the bridge, and acts as captain. He has the same angular vision, hence the same perspective, as on the real ship (the seat being vertically adjustable). The other student fulfils the functions of “helmsman” and “chief engineer”. His eyes are at deck level so that he can follow and observe the manoeuvres performed by the captain and learn from them.

Since the advent of the large “Tractor-Tugs” using different propulsion systems, it is now possible to simulate realistically this new type of vessel at scale 1/25. This is why Port Revel acquired four tractor tugs, two of the VOITH-SCHNEIDER type, one Z-PELLER Azimuthal Stern Drive tug and one CARROUSEL tug. These models are of course too small to be manned. They are radio-controlled by a real tug master. They are able to provide a bollard pull of about 70 Newtons (or 7 kg) i.e. a force close to 100 tons at full scale which at the present time is well in excess of the bollard pull of most existing tugs.

With these models the Port Revel centre is able to provide an “escort” for the larger tanker or LNG tanker models, and to simulate and study realistically all types of emergency manoeuvres in restricted water conditions in case of black-outs and/or engine or rudder failures.

As maritime safety becomes an increasing concern, Port Revel is even more relevant than ever in training ships’ captains and pilots to handle emergency situations. Since 1967, the centre has trained more than 7000 pilots, captains and officers from all over the world.
read more (in English, 7 Mo, pdf, 2014)
See also the official web site of the Port Revel shiphandling training centre, or find out where the famous Pivot Point is located on board a ship (in English, 2 Mo, pdf, 2012) or learn about steering podded ships with the European project AZIPILOT (in English, 6 Mo, pdf, 2012).

Other work and publications:

Submerged breakwaters – An analysis of long term stability of rubble mound breakwaters  was carried out concentrating on the worst possible wave conditions, considering that they will eventually occur in the long term (i.e. only cases with waves breaking between the toe and the crest of the submerged structure were considered). It aims at finding some simple relation between the governing parameters (water depth, structure height, stone size) and the equilibrium position of the crest of rubble mound breakwaters subject to long term wave attack in breaking wave conditions. A few scale model tests were performed confirming the general trend. It is concluded that undersized emerging rubble mound breakwaters reduce to submerged breakwaters and that for a given stone size, submerged breakwaters stabilize to the predicted crest level after long term wave attack in breaking wave conditions.
read more (in English, 1 Mo, pdf, 2013).

Reconstruction of Beirut – Sogreah’s Maritime Division was involved in reconstructing “Beirut Central District” with a large deep water land reclamation on the north coast of the city, near St Georges Hotel and the port of Beirut. Hydraulic design criteria were prepared by Sogreah and preliminary model testing was conducted.
read more (en français, 400 Ko, pdf, 1996).

Rubble mound breakwater stability with multidirectional waves – This paper gives a short description of a three-dimensional physical model study of the effects of directional spreading of random waves on the stability and overtopping of a rubble mound breakwater. The model consisted of a conventional breakwater with four different types of armour (rock, Tetrapod blocks, grooved Antifer cubes and Accropode blocks). It is concluded that armour stability generally increases with increasing directional spreading but some noticeable features concerning oblique multidirectional waves lead to renewed prudence in the design of coastal structure.
read more (in English, 5 Mo, pdf, 1992). This research was part of the European project MAST (in English, 5 Mo, pdf, 1990).

Scale models in hydraulic engineering – Most hydraulics laboratories reduced their facilities in the eighties. So did Sogreah when combining its three labs into one single place in Le Pont de Claix, near Grenoble (France). Hydraulic scale models are used by civil engineers for coastal and river structures since more than one century. The paper gives the main areas in which scale models are still not surpassed by numerical models. And it is believed that this may last for some more time.
read more (en français, 1 Mo, pdf, 1988).

Sediment motion under waves – An attempt was made to establish connections between features of sediment motion in the 3 layers generally considered, i.e. the fluid layer, the bed layer and the subsoil layer. It was found that sheet flow is very common in the bed layer and that fluidisation of the subsoil can occur at the bed surface under wave action.
read more (in English, 1.2 Mo, pdf, 1988).

Wave statistics based on ships’ observations – Wave observations made visually from selected ships are commonly used in coastal engineering for design purposes. The reliability of wave statistics based on ships’ observations appears to be acceptable provided a large number of observations is available and the maximum observed are considered with care. A computer program was developed to process data made available by meteorological offices. Exceedance frequencies, wave roses and wave power distributions can be computed both for deep-water and for shallow-water conditions. Littoral drift and return periods of extreme wave conditions can be computed as well. Some results are presented for the south-western part of the French Mediterranean coast.
read more (in English, 4 Mo, pdf, 1986).

Design criteria for granular filters – A summary of design criteria for granular filters complemented by extensive experimental data is presented. Distinction is made between granular filter constructions subject to steady or cyclic flow parallel or perpendicular to the interface between the fine base material and the coarse filter material. Some combinations of those flow situations are also considered. Some physical explanation of the filter action is given together with new experimental data concerning the influence of a super-imposed load on the behaviour of granular filters and concerning the internal stability of graded filter materials.
read more (in English, 16 Mo, pdf, 1984).

Top layer stability of overflow rockfill dams – An analysis of the most important experimental data available from literature and research carried out at the Delft Hydraulics Laboratory has been performed in order to present a systematic comprehensive picture of the phenomenon and to establish clearly defined design criteria. Design criteria involving maximum acceptable discharges and upstream water levels have been derived for various typical flow conditions, as a function of the hydraulic and structural parameters.
read more (in English, 5 Mo, pdf, 1983).

The closure of tidal basins – The closing of tidal basins generally serves a combination of various purposes, such as land reclamation, protection against floods, creation of fresh-water reservoirs, etc. Closure works in tidal areas will change the tidal conditions on the sea side of the closure, while desalination will be the main problem in the enclosed area. A comparison between some closure methods is given. A distinction is made between sudden and gradual closure methods, the latter being subdivided into vertical, horizontal and combined methods. Some attention is paid also to the seabed protection, which is needed in order to reduce the risk of instability of the closure dam during construction. As an illustration of a large-scale closure operation, a case study has been worked out briefly. From a comparison between a vertical and a combined horizontal and vertical closure method, the latter appears to be less appropriate in the case of large-scale closure works.
read more (in English, 9 Mo, pdf, 1982).

Local scour in non-cohesive sediment – The model-prototype conformity of local scour in experiments with non-cohesive bed material is studied for a case of an overflow dam. A brief description of the time scale and the relationship between time and scour depth established through previous systematic model investigation is given. This relationship and the conformity of the scour holes were verified by means of prototype investigation. The evolutions of scour in time, both in model and in prototype, are presented. Also some considerations are given as to the practical application of the results.
read more (in English, 2 Mo, pdf, 1981).