4.1.1 A vessel which operates in Area Category
0, 1, or 2 should be fitted with a watertight weather deck over the
length of the vessel, satisfying the requirements of Section 4.3.1,
and be of adequate structural strength to withstand the sea and weather
conditions likely to be encountered in the intended area of operation.
4.1.2 A vessel which is not fitted with a watertight
weather deck in accordance with Section 4.1.1 should normally be restricted
to Area Category 3, 4, 5 or 6 and be provided with adequate reserves
of buoyancy and stability for the vessel with its full complement
of persons to survive the consequences of swamping. An open boat should
normally be restricted to service in area categories 4, 5 and 6. A
sailing vessel which is not fitted with a watertight weather deck
should be limited to Area Category 6.
4.1.3 Sections 4.1.3.1 and 4.1.3.2 apply to a
vessel referred to in section 4.1.2
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4.1.3.1 An open boat should not carry cargo, or
a combination of passengers and cargo, for which the cargo element
is in excess of 1000kg (refer to Section 11 Stability and 12 Freeboard). Such a vessel may not be fitted
with a lifting device, or be engaged in towing operations.
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4.1.3.2 A motor vessel fitted with a watertight
weather deck, which does not meet the freeboard requirements of Section 12.2, but which possesses adequate reserves
of buoyancy above the weather deck, may be considered for the operations
defined in Section 4.1.3.1 above, provided the following conditions
are satisfied:-
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.1 Freeboard to the gunwale edge should meet that
required by Section 12.2.2.1.3. Freeboard
to the weather deck should be positive in all loading conditions.
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.2 The recess bounded by the reserve buoyancy
and gunwales should meet the standard for quick-draining cockpits
for Category A vessels, within ISO 11812 - 'Small Craft - Watertight
Cockpits and Quick-draining Cockpits', or equivalent.
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.3 The vessel should comply with the relevant
intact stability criteria for transverse stability, and should display
positive longitudinal stability, for the duration of the drain time.
A diagram showing a suitable type of arrangement for the
purposes of section 4.1.3.2 is shown below. Shaded areas show buoyancy
above the watertight deck, in this case at the vessel sides, but which
may equally be fore and aft.