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Whether it’s
a custom yacht or a new version of a production design, designers and
builders are looking for something that is truly different and does
exactly what they want. But how do they know if the design will work?
They could build it, sea-trial it, and modify it as needed, but such
trial-and-error building gets very expensive very quickly. The more
practical option is to test an exact model of the design—model
testing.
What is model testing,
when is it done, and what kinds of tests are performed? To get the answers,
we consulted several well-known designers.
Model testing involves
moving a small, accurately scaled replica of a boat through a water-filled
towing tank and observing and measuring how it behaves. From these observations,
engineers can make
fairly accurate predictions of how the full-size version will behave
and how much power will be needed for the desired speed. According to
Ed Monk of the design firm Edwin Monk & Sons, “Model tests
can provide valuable information about how a boat will perform, allowing
accurate performance prediction and helping to discover any running
or seakeeping problems while they are easy to correct.”
Jack Sarin of Jack Sarin
Naval Architects says that a truly custom design, which “likely
has a unique hull shape,” and a design “where optimum performance
is particularly critical” make ideal testing candidates. He also
says that testing should be performed early in the design process, “but
only after a couple of circles around the [design] spiral have fleshed
out the issues of weight and trim and a reasonable arrangement has been
settled upon by the client.” It’s also important that the
designer be present for tests. Ed Hageman, a well-respected hydrodynamicist
used by both Sarin and Monk during tests, says, “[The designer]
is the one who knows in detail what ought to happen and easily might be
the only one to notice when something is amiss.”
Next page >
Floating a Design, Part 2 > Page 1, 2,
3
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