2.1.1 Most of the prototype tests required for
certification of free-fall lifeboats are the same as those required
for conventional davit launched lifeboats, e.g., the speed and self-righting
tests. Other tests, e.g., the free-fall tests, are peculiar to and
only conducted with free-fall lifeboats. Through these special free-fall
lifeboat tests, several considerations which are unique to such lifeboats
can be verified. In general, these considerations are:
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.1 The lifeboat must have adequate reserve strength.
This is demonstrated during the overheight drop test .
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. 2 The lifeboat must have adequate strength for
repeated use. This is demonstrated during the free-fall tests .
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. 3 The lifeboat must make positive headway after
water entry. This is also demonstrated during the free-fall tests
.
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. 4 The occupants must be protected from injury
during the free-fall and water entry. This is demonstrated through
acceleration forces measured during the free-fall tests.
2.1.2 Even though much can be learned about the
performance of a free-fall lifeboat through use of models - the use
of models to infer performance is definitely encouraged - there are
some tests that can only be conducted with full-scale boats. It is
not always economically feasible to conduct all these tests before
the prototype certification trials are conducted. The free-fall tests
are typical of such tests because special equipment and towers are
often required for the evaluation. There will always be unknowns when
a boat is tested the first time and failures may result. Such failures
should not be interpreted negatively. They are not necessarily indicative
of an inferior lifeboat or of carelessness on the part of a manufacturer.
Often, more can be learned from a failure than from a success. Regardless,
modifications can be made and the failed tests are usually successful
the second time.
2.1.3 Following is a brief discussion of the intent
of the special free-fall lifeboat tests that are conducted and considerations
during those tests. More thorough discussions about the behavior of
free-fall lifeboats and the bases of methods used to evaluate that
behavior are presented in other sections of this circular.