Four winns FUNSHIP - The.effect.of.boats.moored.along.side; Backdrafting.(Station.wagon.effect)

Owner’s Manual Page 30Boating Safety - Section B
2. Excessive or unequally distributed weight.
Figure B-9: Inefcient trim angles
3. Canvascongurations–Undervariousconditio-
ns, adding or removing canvas may raise or lower
CO levels. See Figures B-8, B-9 & B-11.
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 ventila-
tion 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airowismovingforwardinsidethe
boat, CO may be entering the boat. See Figures
B-10 and B-11.
Figure B-10: Desired air ow through the boat
Figure B-11: The effect of canvas congurations
5. Operating a boat at slow speeds with a following
wind should be avoided. Consider changing direc-
tion, adjusting speed, or both. See Figure
B-12.
J. The Effect of Boats Moored Along Side
A boat operator should be aware that carbon monox-
i
de 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 B7.
Figure B-7: 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 B-8 Backdrafting –
AirowsOverBoatandBehindTransom”.
Figure B-8: Backdrafting - Air ows 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:
1. Intentional or unintentional excessive trim angle
causing high bow angle. See Figure B-9.