8.1 Initial ship design and construction offers
the most comprehensive, effective and durable means by which to minimize
ship biofouling risks. In the design and construction of a ship, or
when a ship is being significantly altered, the following should be
taken into consideration:
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.1 Small niches and sheltered areas should be
excluded from the ship as far as practical, e.g., flush mounting pipes
in sea chests. Where not practical, these should be designed so that
they may be easily accessed for inspection, cleaning and application
of anti-fouling measures.
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.2 Rounding and/or bevelling of corners, gratings
and protrusions to promote more effective coverage of anti-fouling
coating systems, and hinging of gratings to enable diver access.
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.3 Providing the capacity to blank off the sea
chest and other areas, such as moon pools, floodable docks and other
free flood spaces, for treatment and/or cleaning.
8.2 Internal seawater cooling systems should be
designed and made of appropriate material to minimize biofouling and
constructed with a minimum of bends, kinks and flanges in seawater
piping.
8.3 To avoid creation of avoidable niches while
ensuring effective safety and operation of the ship, where practical,
particular attention should be given to avoidance of unfilled gaps
in all skin fittings and the detailed design of the items as follows:
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.1 sea chests – minimize size and number,
and use smooth surfaces to maximize flow efficiency, fit MGPS, and
steam or hot water cleaning systems, grills and their opening arrangements
designed for in-water inspection and maintenance;
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.2 retractable fittings and equipment –
avoid external reinforcement (such as stiffeners) where possible,
design for in-water inspection and maintenance;
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.3 tunnel thrusters – tunnels to be above
light water line or accessible to divers, grills and their opening
arrangements designed for in-water inspection, maintenance and operation;
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.4 sponsons and hull blisters – use fully
enclosed in preference to free flooding types, with access provisions
made for in-water inspection, cleaning and maintenance;
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.5 stern tube seal assemblies and rope guards
– design for in-water inspection, cleaning and maintenance;
and
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.6 immersible and seabed equipment – ensure
facilities for equipment washdown during retrieval and enclosed washdown
areas for cleaning of equipment on board, if necessary, are provided.