6 Lifeboats
6.1 Definitions
and general conditions
6.1.1 Except as specified otherwise, the mass
of an average person as used herein should be taken to be 75 kg for
a lifeboat intended for a passenger ship or 82.5 kg for a lifeboat
intended for a cargo ship.
6.1.2 When weights are placed in the lifeboat
to simulate the effects of an occupant sitting in a seat, the centre
of gravity of the weight in each seat shall be placed 300 mm above
the seat pan along the seat back.
6.2 Lifeboat material
tests
Material fire-retardancy test
6.2.1 The hull and canopy material should be flame
tested to determine its fire-retarding characteristics by placing
a test specimen in a flame. After removal from the flame the burning
time and burning distance should be measured and should be to the
satisfaction of the Administration.
Lifeboat buoyant material test
6.2.2 When inherent buoyant material is required,
the material should be subjected to the tests prescribed in 2.6, other
than 2.6.8, except that in 2.6.6.3 high-octane petroleum spirit should
be substituted for diesel oil.
6.2.3 In addition to the test in 6.2.2, specimens
of the material should be immersed in each of the following for a
period of 14 days under a 100 mm head:
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.1 two specimens in crude oil;
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.2 two specimens in marine fuel oil (grade C);
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.3 two specimens in diesel oil (grade A);
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.4 two specimens in high octane petroleum spirit;
and
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.5 two specimens in kerosene.
6.2.4 The specimens should be tested as supplied
by the manufacturer and at normal room temperature (approximately
18°C).
6.2.5 Two additional specimens, which have already
been subjected to the temperature cycling tests, should be tested
against high octane petroleum spirit and afterwards subjected to the
water absorption test as prescribed in 2.6.5
to 2.6.7.
6.2.6 The dimensions of the specimens should be
recorded at the beginning and end of these tests.
6.2.7 The reduction of buoyancy must not exceed
5% and the specimens should show no sign of damage such as shrinking,
cracking, swelling, dissolution or change of mechanical qualities.
6.3 Lifeboat overload
testDavit-launched lifeboats
6.3.1 The unloaded lifeboat should be placed on
blocks or suspended from the lifting hooks and sights should be erected
for measuring keel sag. The measurements required in 6.3.4 should
then be made.
6.3.2 The lifeboat should then be loaded with
properly distributed weights to represent the fully equipped lifeboat
loaded with the full complement of persons for the type of ship for
which it is to be approved. The measurements required in 6.3.4 should
again be made.
6.3.3 Additional weights should then be added
so that the suspended load is 25%, 50%, 75% and 100% greater than
the weight of the fully equipped and loaded lifeboat. In the case
of metal lifeboats, the testing should stop at 25% overload. The weights
for the various overload conditions should be distributed in proportion
to the loading of the lifeboat in its service condition, but the weights
used to represent the persons need not be placed 300 mm above the
seatpan. Testing by filling the lifeboat with water should not be
accepted as this method of loading does not give the proper distribution
of weight. Machinery may be removed in order to avoid damage to it,
in which case weights should be added to the lifeboat to compensate
for the removal of such machinery. At each incremental overload, the
measurements required in 6.3.4 should be made.
6.3.4 The following should be measured and recorded
at each condition of load specified in 6.3.1 through 6.3.3:
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.1 deflection of keel amidships;
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.2 change in length as measured between the top
of stem and stern posts;
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.3 change in breadth over the gunwale at the quarter
length forward, amidships and the quarter length aft; and
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.4 change in depth measured from gunwale to keel.
6.3.5 The keel deflection and change in breadth
in 6.3.4.1 and 6.3.4.3 should not exceed 1/400th of the lifeboat's
length when the lifeboat is subjected to 25% overload; the results
at 100% overload, if required by 6.3.3, should be approximately in
proportion to those obtained at 25% overload.
6.3.6 The weights should then be removed and the
dimensions of the lifeboat checked. No significant residual deflection
should result. Any permanent deflection as a result of these tests
should be recorded. If the lifeboat is made of GRP, such measurement
should be taken after a lapse of time sufficient to permit the GRP
to recover its original form (approximately 18 h).
Free-fall lifeboats
6.3.7 It should be demonstrated that the lifeboat
has sufficient strength to withstand the forces acting upon it when
loaded with a distributed mass equal to the mass of the number of
persons for which it is to be approved and its equipment when free-fall
launched from a height of 1.3 times the height for which it is to
be approved. If the lifeboat is normally ramp-launched, and a ramp
is not available, this test may be conducted by dropping the lifeboat
vertically with the keel at the same angle that normally occurs during
water entry.
6.3.8 After this test the lifeboat should be unloaded,
cleaned and carefully examined to detect the position and extent of
damage that may have occurred as a result of this test. An operational
test should then be conducted in accordance with 6.10.1. After this test the lifeboat
should again be unloaded, cleaned, and inspected for possible damage.
6.3.9 This test should be considered successful
if the lifeboat passes the operational test to the satisfaction of
the Administration; no damage has been sustained that would affect
the lifeboat's efficient functioning; and any deflections of the hull
or canopy as measured during the test would not cause injury to lifeboat
occupants.
6.4 Davit-launched lifeboat
impact and drop test
Impact test
6.4.1 The fully equipped lifeboat, including its
engine, should be loaded with weights equal to the mass of the number
of persons for which the lifeboat is to be approved. In totally enclosed
lifeboats, representative safety belts and fastenings which will experience
high loads as a result of the impact should be secured about weights
equal to 100 kg to simulate holding a person during the test. The
weights should be distributed to represent the normal loading in the
lifeboat. Skates or fenders, if required, should be in position. The
lifeboat, in a free hanging position, should be pulled laterally to
a position so that when released it will strike a fixed rigid vertical
surface at a velocity of 3.5 m/s. It should be released to impact
against the rigid vertical surface.
6.4.2 In the case of totally enclosed lifeboats,
the acceleration forces should be measured and evaluated in accordance
with 6.17 at different positions
within the prototype lifeboat to determine the most severe occupant
exposure to acceleration considering the effects of fenders, lifeboat
elasticity, and seating arrangement.
Drop test
6.4.3 The fully equipped lifeboat, with its engine,
should be loaded with weights equal to the mass of the maximum number
of persons for which the lifeboat is to be approved. Included in this
loading should be a weight of 100 kg loaded in one of each type of
seat installed in the lifeboat. The remainder of the weights should
be distributed to represent the normal loading condition but need
not be placed 300 mm above the seatpan. The lifeboat should then be
suspended above the water so that the distance from the lowest point
of the lifeboat to the water is 3 m. The lifeboat should then be released
so that it falls freely into the water.
6.4.4 The drop test should be conducted with the
lifeboat that was used in the impact test.
Operational test after impact and drop test
6.4.5 After the impact and drop tests, the lifeboat
should be unloaded, cleaned and carefully examined to detect the position
and extent of damage that may have occurred as a result of the tests.
An operational test should then be conducted in accordance with 6.10.1.
Acceptability criteria for impact and drop tests
6.4.6 After the tests required in this section,
the lifeboat should be unloaded, cleaned, and inspected for possible
damage.
6.4.7 The impact and drop tests should be considered
successful if:
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.1 no damage has been sustained that would affect
the lifeboat's efficient functioning;
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.2 the damage caused by the impact and drop tests
has not increased significantly as a result of the test specified
in 6.4.5;
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.3 machinery and other equipment has operated
to full satisfaction;
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.4 no significant ingress of seawater has occurred;
and
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.5 accelerations measured during the impact and
subsequent rebound, if required during the impact test, are in compliance
with the criteria of either 6.17.9
to 6.17.12 or 6.17.13 to 6.17.17 when using the emergency limits
specified in table 2 or table 3, respectively.
6.5 Free-fall lifeboat
free-fall test
Required free-fall tests
6.5.1 A lifeboat designed for free-fall launching
should be subjected to test launches conducted from the height at
which the lifeboat is intended to be stowed taking into account conditions
of unfavourable list and trim, unfavourable locations of the centre
of gravity, and extreme conditions of load.
6.5.2 During the free-fall launches required in
this section, acceleration forces should be measured and the data
evaluated in accordance with 6.17 at
different locations in the lifeboat to determine the worst occupant
exposure to acceleration taking into consideration the seating arrangement.
6.5.3 The tests required in this section may be
conducted with correctly scaled models that are at least 1 m in length.
As a minimum, the dimensions and mass of the lifeboat, the location
of its centre-of-gravity, and its second moment of mass, must be scaled
in a reasonable manner. Depending on the construction and behaviour
of the free-fall lifeboat, other parameters may also have to be reasonably
scaled to effect correct behaviour of the model. If models are used,
sufficient full-scale tests should be conducted to verify the accuracy
of the model measurements. As a minimum, the following full-scale
tests should be conducted with the ship on an even keel using the
same type of launching arrangement as the production lifeboat and
from the height for which the lifeboat is to be approved:
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.1 lifeboat fully loaded;
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.2 lifeboat loaded with its required equipment
and minimum launching crew only; and
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.3 lifeboat loaded with its required equipment
and one half of the full complement of persons distributed in the
forward half of the seating positions of the lifeboat; and
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.4 lifeboat loaded with its required equipment
and one half of the full complement of persons seated in the after
half of the seating positions of the lifeboat.
Acceptability criteria for free-fall tests
6.5.4 The free-fall tests required in this section
should be considered acceptable if:
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.1 the acceleration forces are in compliance with
the "Training" condition specified in tables 2 and 3 of
6.17 during the launch, free-fall, and subsequent water entry for
those tests with the ship on even keel;
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.2 the acceleration forces are in compliance with
the "Emergency" condition specified in tables 2 and 3 of 6.17 during the launch,
free-fall, and subsequent water entry for those tests with the ship
under unfavourable conditions of list and trim; and
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.3 the lifeboat makes positive headway immediately
after water entry.
6.6 Lifeboat seating
strength test
Davit-launched lifeboats
6.6.1 The seating should be loaded with a mass
of 100 kg in each position allocated for a person to sit in the lifeboat.
The seating should be able to support this loading without any permanent
deformation or damage.
Free-fall lifeboats
6.6.2 The seats experiencing the highest acceleration
forces, and those seats which are supported in a manner different
from the other seats in the lifeboat, should be loaded with a mass
of 100 kg. The load should be arranged in the seat so that both the
seatback and the seatpan are affected. The seating should be able
to support this load during a free-fall launch from a height of 1.3
times the approved height, without any permanent deformation or damage.
This test may be conducted as part of the test in 6.3.7 to 6.3.9.
6.7 Lifeboat seating
space test
6.7.1 The lifeboat should be fitted with its engine
and its equipment. The number of persons for which the lifeboat is
to be approved, having an average mass of 75 kg for a lifeboat intended
for a passenger ship or 82.5 kg for a lifeboat intended for a cargo
ship, and wearing a lifejacket and any other essential equipment,
should be able to board the lifeboat and be properly seated within
a period of 3 min in the case of a lifeboat intended for a cargo ship
and as rapidly as possible in the case of a lifeboat intended for
a passenger ship. The lifeboat should then be manoeuvred and all equipment
on board tested by an individual to demonstrate that the equipment
can be operated without difficulty and without interference with the
occupants.
6.7.2 The surfaces on which persons might walk
should be visually examined to determine that they have a non-skid
finish.
6.8 Lifeboat freeboard
and stability tests
Flooded stability test
6.8.1 The lifeboat should be loaded with its equipment.
If provision lockers, water tanks and fuel tanks cannot be removed,
they should be flooded or filled to the final waterline resulting
from the test in 6.8.3. Lifeboats fitted with watertight stowage compartments
to accommodate individual drinking water containers should have these
containers aboard and placed in the stowage compartments which should
be sealed watertight during the flooding tests. Ballast of equivalent
weight and density should be substituted for the engine and any other
installed equipment that can be damaged by water.
6.8.2 Weights representing persons who would be
in the water when the lifeboat is flooded (water level more than 500
mm above the seat pan) may be omitted. Weights representing persons
who would not be in the water when the lifeboat is flooded (water
level less than 500 mm above seat pan) should be placed in the normal
seating positions of such persons with their centre of gravity approximately
300 mm above the seat pan. Weights representing persons who would
be partly submerged in the water when the lifeboat is flooded (water
level between 0 and 500 mm above the seat pan) should additionally
have an approximate density of 1 kg/dm3 (for example water
ballast containers) to represent a volume similar to a human body.
6.8.3 When loaded as specified in 6.8.1 and 6.8.2,
the lifeboat should have positive stability when filled with water
to represent flooding which would occur when the lifeboat is holed
in any one location below the waterline assuming no loss of buoyancy
material and no other damage. Several tests may have to be conducted
if holes in different areas would create different flooding conditions.
Freeboard test
6.8.4 The lifeboat with its engine should be loaded
with a mass equal to that of all the equipment. One half of the number
of persons for which the lifeboat is to be approved should be seated
in a proper seating position on one side of the centreline. The freeboard
should then be measured on the low side.
6.8.5 This test should be considered successful
if the measured freeboard on the low side is not less than 1.5% of
the lifeboat's length or 100 mm, whichever is greater.
6.9 Release mechanism
testDavit-launched lifeboats
6.9.1 The lifeboat with its engine fitted should
be suspended from the release mechanism just clear of the ground or
the water. The lifeboat should be loaded so that the total mass equals
1.1 times the mass of the lifeboat, all its equipment and the number
of persons for which the lifeboat is to be approved. The lifeboat
should be released simultaneously from each fall to which it is connected
without binding or damage to any part of the lifeboat or the release
mechanism.
6.9.2 It should be confirmed that the lifeboat
will simultaneously release from each fall to which it is connected
when fully waterborne in the light condition and in a 10% overload
condition.
6.9.3 With the operating mechanism disconnected
it should be demonstrated when the lifeboat is loaded with its full
complement of persons and equipment and towed at speeds of 5 knots
that the moveable hook component stays closed. Furthermore, with the
operating mechanism connected, it should be demonstrated that the
lifeboat when loaded with its full complement of persons and equipment
when towed at speeds of 5 knots can be released. Both of the above
should be demonstrated as follows:
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.1 a force equal to 25% of the safe working load
of the hook should be applied to the hook in the lengthwise direction
of the boat at an angle of 45° to the vertical. This test should
be conducted in the aftward as well as the forward direction;
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.2 a force equal to the safe working load of the
hook should be applied to the hook in an athwartships direction at
an angle of 20° to the vertical. This test should be conducted
on both sides; and
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.3 a force equal to the safe working load of the
hook should be applied to the hook in a direction halfway between
the positions of tests 1 and 2 (i.e. 45° to the longitudinal axis
of the boat in plan view) at an angle of 33° to the vertical.
This test should be conducted in four positions.
There should be no damage as a result of these tests.
6.9.4 A release mechanism should be conditioned
and tested as follows:
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.1 the lifeboat release and retrieval system and
the longest used connection cable/linkage associated with the system
should be mounted and adjusted according to instructions from the
original equipment manufacturer and then loaded to 100% of its safe
working load and released. Load and release should be repeated 50
times. During the 50 releases, the lifeboat release and retrieval
system should be released simultaneously from each fall to which it
is connected without any binding or damage to any part of the lifeboat
release and retrieval system. The system should be considered as "failed"
if any failure during the conditioning or unintended release occurs
when load is applied but the system has not yet been operated;
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.2 the lifeboat release and retrieval system should
then be disassembled, the parts examined and wear recorded. The release
and retrieval system should then be reassembled;
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.3 the hook assembly, whilst disconnected from
the operating mechanism, should then be tested 10 times with cyclic
loading from zero load to 1.1 times the safe working load, at a nominal
10 seconds per cycle; unless the release mechanism has been specifically
designed to operate as an off-load hook with on-load capability using
the weight of the boat to close the hook, in this case the cyclic
load should be from no more than 1% to 1.1 times the SWL. For cam-type
designs, the test should be carried out at an initial cam rotation
of 0º (fully reset position), and repeated at 45º in either
direction, or 45º in one direction if restricted by design. The
specimen should remain closed during the test. The system should be
considered as "failed" if any failure during this test or any unintended
release or opening occurs; and
There should be no damage to the hook as a result of this test,
and in the case of a waterborne test, there should be no damage to
the lifeboat or its equipment.
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.4 the cable and operating mechanism should then
be reconnected to the hook assembly; and the lifeboat release and
retrieval system should then be demonstrated to operate satisfactorily
under its safe working load. The actuation force should be no less
than 100 N and no more than 300 N, if a cable is used it should be
the maximum length specified by the manufacturer, and secures in the
same manner it would be secured in the lifeboat. The demonstration
should verify that any interlocks, indicators and handles are still
functioning and are correctly positioned in accordance with the operation
and safety instruction from the original equipment manufacturer. The
release mechanism is deemed to have passed the testing under paragraph
6.9.4 when the tests have been conducted successfully. The system
should be considered as "failed" if any failure during this test or
any unintended release or opening occurs.
6.9.5 A second release mechanism should be tested
as follows:
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.1 the actuation force of the release mechanism
should be measured loaded with 100% of its safe working load. The
actuation force should be no less than 100 N and no more than 300
N. If a cable is used, it should be of the maximum length specified
by the manufacturer, and secured in the same manner it would be secured
in a lifeboat. The demonstration should verify that any interlocks,
indicators and handles are still functioning and are correctly positioned
in accordance with the operation and safety instruction from the original
equipment manufacturer; and
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.2 the release mechanism should be mounted on
a tensile strength testing device. The load should be increased to
at least six times the working load of the release mechanism without
failure of the release mechanism.
Free-fall lifeboats
6.9.6 It should be demonstrated that the free-fall
release mechanism can operate effectively when loaded with a force
equal to at least 200% of the normal load caused by the fully equipped
lifeboat when loaded with the number of persons for which it is to
be approved.
6.9.7 The release mechanism should be mounted
on a tensile strength testing device. The load should be increased
to at least six times the working load of the release mechanism without
failure of the release mechanism.
6.10 Lifeboat operational
test
Operation of engine and fuel consumption test
6.10.1 The lifeboat should be loaded with weights
equal to the mass of its equipment and the number of persons for which
the lifeboat is to be approved. The engine should be started and the
lifeboat manoeuvred for a period of at least 4 h to demonstrate satisfactory
operation. The lifeboat should be run at a speed of not less than
6 knots for a period which is sufficient to ascertain the fuel consumption
and to establish that the fuel tank has the required capacity. The
maximum towing force of the lifeboat should be determined. This information
should be used to determine the largest fully loaded liferaft the
lifeboat can tow at 2 knots. The fitting designated for towing other
craft should be secured to a stationary object by a tow rope. The
engine should be operated ahead at full speed for a period of at least
2 min, and the towing force measured and recorded. There should be
no damage to the towing fitting or its supporting structure. The maximum
towing force of the lifeboat should be recorded on the type approval
certificate.
Cold engine starting test
6.10.2 The engine may be removed from the lifeboat
for this test; however, it should be equipped with accessories and
the transmission that will be used in the lifeboat. The engine, along
with its fuel and coolant, should be placed in a chamber at a temperature
of -15°C.
6.10.3 The temperature of the fuel, lubricating
oil and cooling fluid (if any) should be measured at the beginning
of this test and should not be higher than -15°C. Samples of each
fluid at this temperature should be collected in a container for observation.
6.10.4 The engine should be started three times.
The first two times, the engine should be allowed to operate long
enough to demonstrate that it runs at operating speed. After the first
two starts, the engine should be allowed to stand until all parts
have again reached chamber temperature. After the third start, the
engine should be allowed to continue to run for at least 10 min and
during this period the transmission should be operated through its
gear positions.
Engine-out-of-water test
6.10.5 The engine should be operated for at least
5 min at idling speed under conditions simulating normal storage.
The engine should not be damaged as a result of this test.
Submerged engine test
6.10.6 The engine should be operated for at least
5 min while submerged in water to the level of the centreline of the
crankshaft with the engine in a horizontal position. The engine should
not be damaged as a result of this test.
Compass
6.10.7 It should be determined that the compass
performance is satisfactory and that it is not unduly affected by
magnetic fittings and equipment in the lifeboat.
Survival recovery test
6.10.8 It should be demonstrated by test that
it is possible to bring helpless people on board the lifeboat from
the sea.
6.11 Lifeboat towing
and painter release test
Towing test
6.11.1 It should be demonstrated that the fully
equipped lifeboat, loaded with a properly distributed mass equal to
the mass of the number of persons for which it is to be approved,
can be towed at a speed of not less than 5 knots in calm water and
on an even keel. There should be no damage to the lifeboat or its
equipment as a result of this test.
Davit-launched lifeboat painter release test
6.11.2 It should be demonstrated that the painter
release mechanism can release the painter on a fully equipped and
loaded lifeboat that is being towed at a speed of not less than 5
knots in calm water.
6.11.3 The painter release mechanism should be
tested in several distinct directions of the upper hemisphere not
obstructed by the canopy or other constructions in the lifeboat. The
directions specified in 6.9.3 should
be used if possible.
6.12 Lifeboat light
tests
The lifeboat light should be subjected to the tests prescribed
in 10.1.
6.13 Canopy erection
test
6.13.1 This test is required only for partially
enclosed lifeboats. During the test the lifeboat should be loaded
with the number of persons for which it is to be approved.
6.13.2 If the lifeboat is partially enclosed it
should be demonstrated that the canopy can be easily erected by not
more than two persons.
6.14 Additional tests
for totally enclosed lifeboats
Self-righting test
6.14.1 A suitable means should be provided to
rotate the lifeboat about a longitudinal axis to any angle of heel
and then release it. The lifeboat, in the enclosed condition, should
be incrementally rotated to angles of heel up to and including 180°
and should be released. After release, the lifeboat should always
return to the upright position without the assistance of the occupants.
These tests should be conducted in the following conditions of load:
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.1 when the lifeboat with its engine is loaded
in the normal position with properly secured weights representing
the fully equipped lifeboat with a full complement of persons on board.
The weight used to represent each person, assumed to have an average
mass of 75 kg, should be secured at each seat location and have its
centre of gravity approximately 300 mm above the seatpan so as to
have the same effect on stability as when the lifeboat is loaded with
the number of persons for which it is to be approved; and
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.2 when the lifeboat is in the light condition.
6.14.2 At the beginning of these tests, the engine
should be running in neutral position and:
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.1 unless arranged to stop automatically when
inverted, the engine should continue to run when inverted and for
30 min after the lifeboat has returned to the upright position;
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.2 if the engine is arranged to stop automatically
when inverted, it should be easily restarted and run for 30 min after
the lifeboat has returned to the upright position.
Flooded capsizing test
6.14.3 The lifeboat should be placed in the water
and fully flooded until the lifeboat can contain no additional water.
All entrances and openings should be secured to remain open during
the test.
6.14.4 Using a suitable means, the lifeboat should
be rotated about a longitudinal axis to a heel angle of 180° and
then released. After release, the lifeboat should attain a position
that provides an above-water escape for the occupants.
6.14.5 For the purpose of this test, the mass
and distribution of the occupants may be disregarded. However, the
equipment, or equivalent mass, should be secured in the lifeboat in
the normal operating position.
Engine inversion test
6.14.6 The engine and its fuel tank should be
mounted on a frame that is arranged to rotate about an axis equivalent
to the longitudinal axis of the boat. A pan should be located under
the engine to collect any oil which may leak from the engine so that
the quantity of such oil can be measured.
6.14.7 The following procedure should be followed
during this test:
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.1 start the engine and run it at full speed for
5 min;
-
.2 stop the engine and rotate it in a clockwise
direction through 360°;
-
.3 restart the engine and run it at full speed
for 10 min;
-
.4 stop the engine and rotate it in a counter-clockwise
direction through 360°;
-
.5 restart the engine, run it at full speed for
10 min, and then stop the engine;
-
.6 allow the engine to cool;
-
.7 restart the engine and run it at full speed
for 5 min;
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.8 rotate the running engine in a clockwise direction
through 180°, hold at the 180° position for 10 s, and then
rotate it 180° further in a clockwise direction to complete one
revolution;
-
.9 if the engine is arranged to stop automatically
when inverted, restart it;
-
.10 allow the engine to continue to run at full
speed for 10 min;
-
.11 shut the engine down and allow it to cool;
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.12 repeat the procedure in 6.14.7.7 through 6.14.7.11
, except that the engine should be turned in a counter-clockwise direction;
-
.13 restart the engine and run it at full speed
for 5 min;
-
.14 rotate the engine in a clockwise direction
through 180° and stop the engine. Rotate it 180° further to
complete a full clockwise revolution;
-
.15 restart the engine and run it at full speed
for 10 min;
-
.16 repeat the procedure in 6.14.7.14 , turning
the engine counter-clockwise;
-
.17 restart the engine, run it at full speed for
10 min and then shut it down; and
-
.18 dismantle the engine for examination.
6.14.8 During these tests, the engine should not
overheat, fail to operate, or leak more than 250 ml of oil during
any one inversion. When examined after being dismantled the engine
should show no evidence of overheating or excessive wear.
6.15 Air supply test
for lifeboats with a self-contained air support system
All entrances and openings of the lifeboat should be closed,
and the air supply to the inside of the lifeboat turned on to the
design air pressure. The engine should then be run at revolutions
necessary to achieve full speed with the fully loaded boat including
all persons and with the sprinkler system in use for a period of 5
min, stopped for 30 s, then restarted for a total running time of
10 min. During this time the atmospheric pressure within the enclosure
should be continuously monitored to ascertain that a small positive
air pressure is maintained within the lifeboat and to confirm that
noxious gases cannot enter. The internal air pressure should never
fall below the outside atmospheric pressure, nor should it exceed
outside atmospheric pressure by more than 20 hPa during the test.
It should be ascertained, by starting the engine with air supply turned
off, that when the air supply is depleted, automatic means are activated
to prevent a dangerous underpressure of more than 20 hPa being developed
within the lifeboat.
6.16 Additional tests
for fire-protected lifeboats
Fire test
6.16.1 The lifeboat should be moored in the centre
of an area which is not less than five times the maximum projected
plan area of the lifeboat. Sufficient kerosene should be floated on
the water within the area so that when ignited it will sustain a fire
which completely envelops the lifeboat for the period of time specified
in 6.16.3 . The boundary of the area should be capable of completely
retaining the fuel.
6.16.2 The engine should be run at full speed;
however, the propeller need not be turning. The gas- and fire-protective
systems should be in operation throughout the fire test.
6.16.3 The kerosene should be ignited. It should
continue to burn and envelop the lifeboat for 8 min.
6.16.4 During the fire test, the temperature should
be measured and recorded as a minimum at the following locations:
-
.1 at not less than 10 positions on the inside
surface of the lifeboat;
-
.2 at not less than five positions inside the
lifeboat at locations normally taken by occupants and away from the
inside surface; and
-
.3 on the external surface of the lifeboat.
The positions of such temperature recorders should be to the
satisfaction of the Administration. The method of temperature measurement
should allow the maximum temperature to be recorded.
6.16.5 The atmosphere inside the lifeboat should
be continuously sampled and representative retained samples should
be analysed for the presence and quantity of essential, toxic, and
injurious gases or substances. The analysis should cover the range
of anticipated gases or substances that may be produced and which
can vary according to the materials and fabrication techniques used
to manufacture the lifeboat. The analysis should indicate that there
is sufficient oxygen and no dangerous levels of toxic or injurious
gases or substances.
6.16.6 The pressure inside the lifeboat should
be continuously recorded to confirm that a positive pressure is being
maintained inside the lifeboat.
6.16.7 At the conclusion of the fire test, the
condition of the lifeboat should be such that it could continue to
be used in the fully-loaded condition.
Note The Administration may waive this test for any totally
enclosed lifeboat which is identical in construction to another lifeboat
which has successfully completed this test, provided the lifeboat
differs only in size, and retains essentially the same form. The protective
system should be as effective as that of the lifeboat tested. The
water delivery rate and film thickness at various locations around
the hull and canopy should be equal to or exceed the measurements
made on the lifeboat originally fire tested.
Water spray tests
6.16.8 Start the engine and the spray pump. With
the engine running at its designed output, the following should be
measured to obtain the rated value and speed:
6.16.9 With the lifeboat in an upright position,
on an even keel and in the light condition, run the pump at the rated
speed. Measure the delivery rate of water or the thickness of the
sprayed water film at the external surface of the lifeboat. The delivery
rate of water or the sprayed water film thickness over the lifeboat
should be to the satisfaction of the Administration.
6.16.10 Successively trim the lifeboat 5°
by the head and 5° by the stern, and heel it 5° to port and
5° to starboard. In each condition the sprayed water film should
cover the whole surface of the lifeboat.
6.17 Measuring and evaluating
acceleration forces
Selection, placement and mounting of accelerometers
6.17.1 The accelerometers used to measure the
acceleration forces in the lifeboat should:
-
.1 have adequate frequency response for the test
in which they are to be used but the frequency response should at
least be in the range of 0 to 200 Hz;
-
.2 have adequate capacity for the acceleration
forces that will occur during the tests;
-
.3 have an accuracy of ± 5%.
6.17.2 Accelerometers should be placed in the
lifeboat, parallel to the principal axes of the lifeboat, at those
locations necessary to determine the worst occupant exposure to acceleration.
6.17.3 The accelerometers should be mounted on
a rigid part of the interior of the lifeboat in a manner to minimize
vibration and slipping.
6.17.4 A sufficient number of accelerometers should
be used at each location at which acceleration forces are measured
so that all likely acceleration forces at that location can be measured.
6.17.5 The selection, placement, and mounting
of the accelerometers should be to the satisfaction of the Administration.
Recording method and rate
6.17.6 The measured acceleration forces may be
recorded on magnetic media as either an analog or a digital signal
or a paper plot of the acceleration signal may be produced.
6.17.7 If the acceleration forces are to be recorded
and stored as a digital signal, the sampling rate should be at least
500 samples per second.
6.17.8 Whenever an analog acceleration signal
is converted to a digital signal, the sampling rate should be at least
500 samples per second.
Evaluation with the dynamic response model
6.17.9 The dynamic response model is the preferred
method to evaluate potential for the occupant in a lifeboat to be
injured by exposure to acceleration forces. In the dynamic response
model, the human body is idealized as a single-degree-of-freedom spring-mass
acting in each co-ordinate direction as shown in figure 3. The response of the
body mass relative to the seat support, which is excited by the measured
accelerations, can be evaluated using a procedure acceptable to the
Administration. The parameters to be used in the analysis are shown
in table 1 for each co-ordinate
direction.
Figure 3 Independent single-degree-of-freedom representation of human
body
Table 1 Parameters of the
Dynamic Response Model
|
Co-ordinate axis
|
Natural frequency
(rad/s)
|
Damping ratio
|
| X
|
62.8
|
0.100
|
| Y
|
58.0
|
0.090
|
| Z
|
52.9
|
0.224
|
6.17.10 Before performing the dynamic response
analysis, the measured accelerations should be oriented to the primary
axes of the seat.
6.17.11 The desired outcome from the dynamic response
analysis is the displacement time-history of the body mass relative
to the seat support in each co-ordinate direction.
6.17.12 At all times, the following expression
should be satisfied:
where
|
d
x, d
yand d
z
|
= |
are the concurrent relative displacements
of body mass with respect to the seat support, in the x, y, and z body axes, as computed from the dynamic
response analysis and S
x, S
y,
and S
z are relative displacements which are
presented in table 2 for
the appropriate launch condition.
|
Table 2 Suggested
Displacement Limits for Lifeboats
|
Acceleration direction
|
Displacement (cm)
|
|
Training
|
Emergency
|
| +X-Eyeballs in
|
6.96
|
8.71
|
| -X-Eyeballs out
|
6.96
|
8.71
|
| +Y-Eyeballs right
|
4.09
|
4.95
|
| -Y-Eyeballs left
|
4.09
|
4.95
|
| +Z-Eyeballs down
|
5.33
|
6.33
|
| -Z-Eyeballs up
|
3.15
|
4.22
|
Evaluation using the SRSS method
6.17.13 In lieu of the procedure in 6.17.9 to
6.17.12 , the potential for an occupant in a lifeboat to become injured
by an acceleration can be evaluated using the procedure presented
in this section.
6.17.14 Before performing the SRSS analysis, the
measured accelerations should be oriented to the primary axes of the
seat.
6.17.15 Full-scale acceleration data should be
filtered with no less than the equivalent of a 20 Hz low pass filter.
Any filtering procedure acceptable to the Administration may be used.
6.17.16 Acceleration data measured on a model
should be filtered with a low pass filter having a frequency not less
than that obtained with the following expression:
where
|
fmodel
|
= |
is the frequency
of the filter to be used, Lmodel is the length of the model
lifeboat, and Lprototype is the length of the prototype
lifeboat.
|
6.17.17 At all times, the following expression
should be satisfied:
where
|
g
x, g
y,
and g
z
|
= |
are the concurrent accelerations
in the x, y, and z seat axes
and G
x, G
y and G
z are allowable accelerations which are presented in table 3 for the appropriate launch
condition.
|
Table 3 SRSS Acceleration
Limits for Lifeboats
|
Acceleration direction
|
Acceleration
|
|
Training
|
Emergency
|
| +X-Eyeballs in
|
15.0
|
18.0
|
| -X-Eyeballs out
|
15.0
|
18.0
|
| +Y-Eyeballs right
|
7.0
|
7.0
|
| -Y-Eyeballs left
|
7.0
|
7.0
|
| +Z-Eyeballs down
|
7.0
|
7.0
|
| -Z-Eyeballs up
|
7.0
|
7.0
|
|