Instruction manual

PROFICIENCY IN SURVIVAL CRAFT AND RESCUE BOATS OTHER THAN
FAST RESCUE BOATS
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6.5 Launching survival craft and rescue boats in rough sea
6.5.1 Use of wave-quelling oil with small boats
When engaged in heavy seas, where excessive pitching is being
experienced, the prudent use of oil on the surface of the water can effectively
reduce the motion of the boat. One gallon of oil is provided as standard issue to
all lifeboats. This oil is usually an animal or vegetable oil, rather than a mineral
oil. Coxswain are advised that the use of oil in limited quantities should prevent
waves from breaking over the craft and so reduce the violent movement on the
craft. The oil will not reduce any swell effects.
It is normal practice to use the oil bag in conjunction with the sea anchor
and heave the boat to, with the intention of riding the bad weather out. A small
amount of oil is used at any one time, ideally spread ahead of the craft to form an
advancing slick giving full benefit to the boat. In a towing operation the oil should
similary be spread from the fore part of the towing vessel. This will benefit both
craft, the tug and the towed vessel.
Heavy oils tends to be better than lighter oils and prevent solid water
landing on the top of the craft. The obvious danger is that the boat could be
swamped or stove in with large waves. Comparing the pollution aspect of the use
of oil with the safety of line, the priority must be in favour of safety of life at sea.
Fig. 6.12 Using of oil bag and sea anchor