Four winns 258 VISTA, Owner'S Manual

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Owner’s Manual Page Boating Safety - Section B
Figure B10: Inefficient trim angles.
3. Canvas Configurations - Under various conditio-
ns, adding or removing canvas may raise or lower
CO levels. See Figures B9, B10 & B12.
Exhaust Fumes!
Hull exhaust from your boat can cause
excessive accumulation of poisonous carbon
monoxide gas within cockpit areas when using
protective weather coverings (while underway
or while stationary). Provide adequate
ventilation when the canvas top, side curtains
and/or back (aft) curtains are in their closed
protective positions.
4. Opening and closing ports, hatches, doors, and
windows may raise or lower CO levels on board a
boat. When airflow is moving forward inside the boat,
CO may be entering the boat. See Figures B11
and B12.
Figure B11: Desired air flow through the boat.
Figure B12: The effect of canvas configurations.
5. Operating a boat at slow speeds with a following
wind should be avoided. Consider changing
direction, adjusting speed, or both.
See Figures B13.
J. The Effect of Boats Moored Alongside
A boat operator should be aware that carbon monox-
ide is emitted from any boat’s exhaust. The operation,
mooring, and anchoring in an area containing other
boats may be in an atmosphere containing CO not
of the operator’s making. An operator likewise needs
to be aware of the effect of their boat on other boats
in the area. Of prime concern is the operation of an
auxiliary generator where boats are moored along
side each other. Be aware of the effect your exhaust
may have on other boats and be aware that the
operation of other boats’ equipment may affect the
carbon monoxide concentration on your boat.
See Figure B8.
Figure B8: The effect of boats moored along side.
K. Backdrafting (Station Wagon Effect)
Backdrafting or the “station wagon effect” is caused by
air movement over or around a boat creating a low
pressure area or suction area around the stern that
can increase CO level on the boat. Backdrafting can
be affected by relative wind direction , boat speed,
and boat trim angle. See Figure B9 Backdrafting -
Airflows Over Boat and Behind Transom”.
Under certain speed and operating conditions the low
pressure area may form in other regions and permit
carbon monoxide to enter the hull through openings
that are not on the back of the boat. Boat factors
which may affect CO concentration:
Figure B9: Backdrafting - Air flows over boat
and behind transom.
1. Intentional or unintentional excessive trim angle
causing high bow angle. See Figure B10.
2. Excessive or unequally distributed weight.