11.6.1 For the purposes of Section 11 only, a
lifting device does not include a person retrieval system, the vessel's
own anchor handling equipment, or davits for tenders, where judged
by the Certifying Authority not to have a detrimental effect on the
stability of the vessel.
11.6.2 Reference should be made to Section 25.4 for requirements for safety standards other than
stability for a vessel fitted with a deck crane or other lifting device.
11.6.3 A vessel fitted with a deck crane or other
lifting device should be a decked vessel (or assessed in accordance
with Section 4.1.3.2) and comply with the
general requirements of Section 11, which are appropriate to it.
In addition, with the vessel in the worst anticipated service
condition for lifting operations, compliance with the following criteria
should be demonstrated by a practical test or by calculations.
-
.1 With the crane or other lifting device operating
at its maximum load moment, with respect to the vessel, the angle
of heel generally should not exceed 7 degrees or that angle of heel
which results in a freeboard to deck edge anywhere on the periphery
of the vessel of 250mm, whichever is the lesser angle. (Consideration
should be given to the operating performance of cranes or other lifting
devices of the variable load-radius type and the load moment with
respect to the vessel for lifting devices situated off centreline).
-
.2 When an angle of heel greater than 7 degrees
but not exceeding 10 degrees occurs, the Certifying Authority may
accept the lifting condition providing that all the following criteria
are satisfied when the crane or other lifting device is operating
at its maximum load moment:-
-
.1 the range of stability from the angle of static
equilibrium to downflooding or angle of vanishing stability, whichever
is the lesser, is equal to or greater than 20 degrees;
-
.2 the area under the curve of residual righting
lever, up to 40 degrees from the angle of static equilibrium or the
downflooding angle, if this is less than 40 degrees, is equal to or
greater than 0.1 metre-radians; and
-
.3 the minimum freeboard to deck edge fore and
aft throughout the lifting operations should not be less than half
the assigned freeboard to deck edge at amidships. For vessels with
less than 1000mm assigned freeboard to deck edge amidships the freeboard
fore or aft should not be less than 500mm.
-
.4 the freeboard to deck edge anywhere on the
periphery of the vessel is at least 250 mm.
11.6.4 Information and instructions to the skipper
on vessel safety when using a deck crane or other lifting device should
be included in the Stability Information Booklet. The information
and instructions should include:-
-
.1 the maximum permitted load and outreach which
satisfy the requirements of Section 11.6.2, or the Safe Working Load
(SWL), whichever is the lesser (operating performance data for a crane
or other lifting device of variable load-radius type should be included
as appropriate);
-
.2 details of all openings leading below deck
which should be secured weathertight; and
-
.3 the need for all personnel to be above deck
before lifting operations commence.
11.6.5 Requirements for a lifting system which
incorporates counterbalance weight(s) or vessels that cannot comply
with the requirements of Section 11.6.2 but is deemed to have adequate
residual stability should be specially considered by the MCA.