MEN AGAINST THE SEA 
17 
waters, especially near river mouths, and are not likely to be 
found far from land. 
SHARKS 
Several species of shark have been known to attack a swim- 
ming man. Your chances of encountering one of these are not 
great. Care, however, should be taken to avoid unnecessary 
risks such as trailing hands or feet from the side of a boat 
or raft, or going into the water when sharks are near. Sharks 
sometimes rub against lifeboats or rafts. This is done to 
scratch off sea lice rather than as an attempt to overturn the 
boat. The nose is their most sensitive spot and a blow here 
may drive them away. Kicking, slapping the water, and shout- 
ing may also have the same effect. Shark repellents should be 
used if available. Shark yarns are usually exaggerated, but 
there are enough authentic records of shark attacks to justify 
all precautions. Whales are practically never dangerous to 
men. If their proximity becomes uncomfortable two pieces of 
metal struck together under water may drive them away. 
Splashing or beating on the surface of the water, however, is 
likely to attract them. 
NAVIGATION WITHOUT INSTRUMENTS 
Navigation in a rubber life raft is of necessity most elemen- 
tary. As a survival factor its role is generally a minor one. 
Fine distinctions as to courses, bearings, speeds, etc., have little 
value due to the extremely limited maneuverability of a raft. 
However, a general knowledge as to one’s approximate where- 
abouts is surely a matter of interest in any case and under 
