by
Stuart M Roy
Naval Architect and Surveyor
Stuart M Roy
Naval Architect and Surveyor
YACHT & POWERCRAFT DESIGN SERVICES
Systematic towing tank tests on new designs have been performed in England for over 130 years. This valuable technique uses an accurate scale model of a newly designed boat, which is then pulled along a channel of water by a carriage running on rails. As the model is towed, the resistance force is measured at a range of speeds by a dynamometer mounted on the carriage. A variety of other forces and measurements are also recorded. Nowadays the data are generally captured, filtered and processed by computer.
The model of the boat is tested in a simulated sailing condition. In Photograph (1) the prototype of a Mini-Transat racer with twin rudders is being tested at 5.4 knots and 20 degrees of heel. As well as avoiding potentially expensive errors in a new design, towing tank testing, together with specialist calculation routines can now predict the performance of a new boat long before it is built.
Dynamic model tests also enable the wash and spray patterns to be observed (2). Items such as spray rails and exhaust outlets can then be positioned accurately on the hull.
The physical effects observed during a tank test are just as important as the recorded measurements. The purpose of this test (3) is to look at the wake wash interaction behind a new sailing catamaran and to determine the optimum separation for the hulls.
The Southampton Institute towing tank facilities also provide a wave-making capability by generating a simulated sea spectrum. In this way it is possible to indicate how a proposed boat or yacht will perform in waves at sea. Static tests for stability, rolling and flooding work can also be performed in a tank facility.
In photograph (4) a scale model of my design for a fast, stable, modern Lifeboat is being put through a full 360 degree stability test.
Yes! - it was fully self-righting.
The model of the boat is tested in a simulated sailing condition. In Photograph (1) the prototype of a Mini-
Dynamic model tests also enable the wash and spray patterns to be observed (2). Items such as spray rails and exhaust outlets can then be positioned accurately on the hull.
The physical effects observed during a tank test are just as important as the recorded measurements. The purpose of this test (3) is to look at the wake wash interaction behind a new sailing catamaran and to determine the optimum separation for the hulls.
The Southampton Institute towing tank facilities also provide a wave-
In photograph (4) a scale model of my design for a fast, stable, modern Lifeboat is being put through a full 360 degree stability test.
Yes! -
Tank Testing of Yachts & Boats 2
If you have a high speed internet link, then click here to see short video clips from recent tank tests on yachts and power boats.
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