push the bow so the boat is parallel to the
waves, which is very dangerous in high seas.
The helmsman must set the angle
that maintains steerage control and use the
throttle. Reduce throttle as you near the
top of the wave; slow down on downslope
side of wave to avoid digging in.
Wave heights vary. Choose the most
favorable path. Look ahead, avoid periodic
unusually high waves. Treat large boat
wakes in a similar manner.
Running Before the Waves
Running before the waves in a planing boat
requires keeping the stern square to the
waves and running on the back of a single
wave.
• You may be fooled by the relative calm
because you are going with the wind.
Check wave heights before attempting to
go over the back of a wave.
• Use engine power to maintain a position
about a third of the way back from the
wave’s crest.
• Be ready to adjust speed faster or slower
to maintain steerage and control. In a
slow displacement vessel, you may not be
able to keep up with a single wave (Figure
11-14).
Section 11: Adverse Conditions and Emergencies 131
• If you cannot keep up with a single wave,
concentrate on keeping the boat centered
with its stern square to the waves coming
up behind you, allowing successive waves
to pass under your keel.
• In high seas, there is a danger of going
over the top of the wave to the steep slope
beyond. This may result in the bow digging
in and possible pitch-poling (stern
over bow), or turning the boat parallel to
the waves.
Running Parallel to the Waves
Running parallel to the waves is often
uncomfortable and potentially is dangerous.
Larger waves (large relative to the size
of the boat) can capsize the boat by rolling
it over (see Figure 11-15). To avoid this,
you may need to head into the waves even
if that direction is somewhat away from
your destination. Your boat will handle
better headed into the waves.
Even relatively small waves can start
a pendulum motion (from side to side) in
your boat if they strike you on the beam.
If the spacing between successive waves
happens to coincide with the natural roll
period of the boat, each successive wave
can give an additional push, resulting in
greater and greater roll until the boat actually
rolls over.
If you must run parallel to the waves,
plan in advance and turn rapidly to reverse
Figure 11-13. Crossing large waves
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Figure 11-14. Running before the waves