IMPLEMENTATION OF THE REQUIREMENTS RELATING TO LIFEBOAT RELEASE AND RETRIEVAL
SYSTEMS
Paragraphs 4.4.7.6.6 and 4.4.7.6.7.2
1 The reset function as required by paragraph 4.4.7.6.6 should also apply to the "other
means" or "similar device" referred to in paragraph 4.4.7.6.7.2.
2 Where a safety pin is fitted to facilitate compliance with SOLAS regulation III/1.5
then, in line with paragraph 4 of the annex to MSC.1/Circ.1327, the safety pin arrangement should be acceptable to the hook
manufacturer, as defined in paragraph 9.9 of the annex to MSC.1/Circ.1392.
Paragraph 4.4.7.6.9
1 All interlocks ("mechanical protection" of on-load release), which include hydrostatic
components in the operating mechanism, should also be of material corrosion resistant in
the marine environment.
2 Where stainless steel having a Pitting Resistance Equivalent Number (PREN)footnote of 22 or more is chosen, such stainless steel does not need
to be subjected to standard ISO 9227:2012 or other equivalent recognized national
standard.
3 Where stainless steel having a PREN < 22, or another corrosion resistant
material/alloy is chosen, the material should be qualified by corrosion test according
to standard ISO 9227:2012 or other equivalent recognized national standard. When the
test is carried out in accordance with standard ISO 9227:2012, neutral salt spray (NSS)
should be used, with 1,000 hours test duration for components outside the lifeboat, and
160 hours for those inside the lifeboat. The salt spray tests may be conducted by using
round specimens (diameter is 14 mm) according to IACS UR W2.4.2.
4 After the salt spray test, the release mechanism should be subjected to load and
release test as described in resolution MSC.81(70), as amended by resolution MSC.321(89), part 1, paragraph 6.9.4.1, to demonstrate satisfactory
operation. The load and release should be repeated 10 times. Where specimens are used
for the salt spray tests, tensile tests should be conducted in lieu of the load and
release test. The results from the tests should be in order to verify that the reduction
in the ultimate tensile strength and reduction in cross sectional area ratio is less
than 5% between corrosion tested and non-corrosion tested specimens.
5 Where austenitic stainless steels (e.g. 316L or 316) are used for welded structures,
the risk of sensitization to intergranular corrosion should be addressed by the
component manufacturer's quality control system.
6 Austenitic stainless steels 201, 304, 321, 347 are susceptible to pitting and crevice
corrosion and, therefore, unsuitable for these applications. For operating cables
covered with sheath and installed inside the lifeboat, inner cables made of austenitic
stainless steels 304 are acceptable without the corrosion test above.
Paragraph 4.4.7.6.14
The hanging-off arrangement, including the connections to the lifeboat release and
retrieval system and davit, should be designed with a calculated factor of safety of 6
based on the ultimate strength of the materials used, and mass of the lifeboat when
loaded with its full complement of fuel and equipment plus 1,000 kg equally distributed
between the falls.