What is a Model Basin?

A model basin is a structure designed for the testing of scale model vessels. The tanks in a model basin can be used to test a scale model of the design of anything that is impacted by the principles of hydrodynamics before that object is built in full scale. Because of the Law of Similitude introduced by William Froude in the late 1880’s, we know that a model of a ship form can be tested under a variety of conditions and the results of those tests will accurately predict the performance of a full sized vessel of the same design. This testing allows the design to be perfected before construction of a full sized vessel is undertaken.

What does a model basin look like

Ice Tank Ship Test

Ice Tank Ship Test

In a model basin, there are pools and long raised “trenches” of water for the testing of models. The models are towed by an apparatus that sits above the surface of the water, yet moves the model through the water at the desired speed. The towing apparatus sits above the surface so that it does not disturb the surface with its motion. Because of this, the conditions in the water are determined only by the factors being tested. Because of this, the models can be accurately tested with large waves, small waves, no waves, ice, no ice … It depends what data is being sought.

In a large pool, it is possible for a scale model of a ship or submarine to appear the same size as a ship or submarine on the open ocean. Wave makers create the desired conditions. It is even possible to simulate a beach. In a” trench,” model performance is tested in a variety of other conditions at varying speeds. One type of test might be to determine the optimum hull configuration.

For test results to be accurate, it is imperative that the waves from one test dissipate fully before a second test is undertaken. To help with this, model basin” trenches” are equipped with apparatus that allows the disrupted surface water to flow out the sides like the vents in a swimming pool. At either end of the “trench” there are waves dissipaters. The round tanks, or pools, have similar mechanisms.

Why model test

Scale model testing first began at the end of the nineteenth century. It was at this time that science was being used to augment processes based upon the accumulation of experience over the ages. As ships went from being made of wood to being made of metal, the cost of the ships went up accordingly. There was also nothing to act as a reference point to what had worked before with these new materials and technologies. In order to avoid costly errors, there had to be a way to test the designs before construction of the actual vessel was undertaken.

Enter William Froude and his proposal for a model basin and model testing. As a result of his tenacity and proven results, scale model testing is now an everyday occurrence in model basins around the world.

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Check out Part III of Modeling Ships and Space Craft

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