5.1 The model experiments should be carried out
in long-crested, irregular waves. The Pierson-Moskovitz, JONSWAP,
or Bretschneider wave spectrum generated for the purpose of these
experiments should have a significant wave height of approximately
8.5 m at the most unfavourable realistic wave period (zero crossing)
as determined by calculation or previous testing experience.
5.2 For ships operating in restricted areas only,
the Administration may allow other spectra.
5.3 The effect of wind generated spray need not
be simulated during the tests.
5.4 The model experiments should be carried out
for at least the following wave directions based on International
Towing Tanks Conference conventions:
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.1 following seas (0°/360°)
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.2 quarter following seas (45°/315°)
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.3 beam seas (90°/270°)
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.4 quarter head seas (135°/225°)
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.5 head seas (180°)
5.5 The model experiments should be carried out
for at least the following speeds:
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.1 maximum sustained speed in head seas and quarter
head seas;
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.2 minimum ship manoeuvring speed in quarter following
seas and following seas;
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.3 zero ship speed (dead ship condition) in beam
seas.
5.6 The Administration may require additional
tests.
5.7 The model experiments should be carried out
with a self-propelled, unrestrained model without the necessity to
change course and the time period of each experiment should correspond
to at least one hour real time.
5.8 The loading condition used for the tests should
correspond at least to the maximum loaded draught with level trim.
If operational trim values differ substantially from level trim, additional
trim values should be included in the model test programme.
5.9 The KG value selected should correspond to
the actual value most likely to be encountered during the ship's service.
If KG values which may be expected during the operation of the ship
differ substantially from this selected KG value, additional KG values
should be included in the model test programme.
5.10 For each test condition, the cargo hold which
ships most water should be determined by preliminary tests for each
combination of heading, trim and KG. In running tests for the full
duration specified above, this least favourable hold should be simulated
as having no containers, whilst other cargo holds (each cargo hold
as a separate entity) may be simulated as completely fully loaded
with containers above the line of the weather deck (or hatch coaming
where applicable). Containers should not be used as a means to prevent
shipping of water into an empty hold where they are stacked outboard
of the open hold. Rain covers for the open holds should not be simulated
in the model tests.
5.11 In additional to the usual parameters measured
(ship motions, ship speed, relative motions, rudder angles, etc.)
the volume of water entering all open cargo holds should be measured
for each experiment. The quantities of water taken aboard the model
should be removed and measured after each test run so that the metacentric
height, moment of inertia and displacement are not appreciably disturbed
by any accumulation of water during the testing programme.
5.12 Where freeing ports are fitted, an additional
model test to comply with 2.1.2 should
be conducted at a draught which corresponds to the condition of the
ship fully loaded with cargo and open holds flooded to the static
equilibrium level with freeing ports open. A hold permeability of
70% by volume should be assumed. Tests should be conducted at zero
speed in beam seas.
5.13 The Administration may require an observer
to witness the tests. A comprehensive report should be submitted to
the Administration.