CFR 46, CA Transport, ABYC et all.
ABYC states that the bilge blower should be located below the engine in an enclosed space containing gasoline powered equipment. It is part of a document that you have to purchase, and are not supposed to share with anyone that has not already purchased it............. Don't ask what I think of that organization......
CFR Part 46 is more applicable, and states the following really long bit inserted at the bottom.
Basically you want to have the blower under the engine. Now I do that on my personal boat with a duct, although technically that is not completely correct, as the blower should not be installed in the duct.
Regulations aside, make sure that you are safe, have the duct that sucks or the blower located below the engine. Gasoline fumes need to be removed from the engine area, and kept out of the bilge. Propane too!
I used to have some photos of a boat that had been in an explosion here, can't find them now.,.. Most of the deck was missing. The injuries were severe, loss of several limbs etc.
Canada transportation board small craft is much more helpful and readable in this regard. and can be found here: Then again the Canadians always seem to be helpful.....
http://www.tc.gc.ca/marinesafety/tp/tp1332/section6.htm#blowers
ABYC would be happy to sell you their recommendations for $50.00. They are in the business to make a lot of MONEY, they are not there to help you the boater.
http://www.abycinc.org/standards/purpose.cfm#H2
Here is the text of CFR 46.
:
"§ 182.460 Ventilation of spaces containing
machinery powered by, or
fuel tanks for, gasoline.
(a) A space containing machinery
powered by, or fuel tanks for, gasoline
must have a ventilation system that
complies with this section and consists
of:
(1) For an enclosed space:
(i) At least two natural ventilation
supply ducts located at one end of the
space and that extend to the lowest
part of the space or to the bilge on
each side of the space; and
(ii) A mechanical exhaust system
consisting of at least two ventilation
exhaust ducts located at the end of the
space opposite from where the supply
ducts are fitted, which extend to the
lowest part of the bilge of the space on
each side of the space, and which are
led to one or more powered exhaust
blowers; and
(2) For a partially enclosed space, at
least one ventilation duct installed in
the forward part of the space and one
ventilation duct installed in the after
part of the space, or as otherwise required
by the cognizant OCMI. Ducts
for partially enclosed spaces must have
cowls or scoops as required by paragraph
(i) of this section.
(b) A mechanical exhaust system required
by paragraph (a)(1)(ii) of this
section must be such as to assure the
air changes as noted in Table 182.460(b)
depending upon the size of the space.
TABLE 182.460(b)
Size of space in cubic meters (feet) Minutes per air
Over Not over change
0 14 (500) 2
14 (500) 28.50 (1000) 3
28.50 (1000) 43 (1500) 4
43 (1500) .............................. 5
(c) An exhaust blower motor may not
be installed in a duct, and if mounted
in any space required to be ventilated
by this section, must be located as high
above the bilge as practicable. Blower
blades must be nonsparking with reference
to their housings.
(d) Where a fixed gas fire extinguishing
system is installed in a space,
all powered exhaust blowers for the
space must automatically shut down
upon release of the extinguishing
agent.
(e) Exhaust blower switches must be
located outside of any space required
to be ventilated by this section, and
must be of the type interlocked with
the starting switch and the ignition
switch so that the blowers are started
before the engine starter motor circuit
or the engine ignition is energized. A
red warning sign at the switch must
state that the blowers must be operated
prior to starting the engines for
the time sufficient to insure at least
one complete change of air in the space
served.
(f) The area of the ventilation ducts
must be sufficient to limit the air velocity
to a maximum of 10 meters per
second (2,000 feet per minute). A duct
may be of any shape, provided that in
no case will one cross sectional dimension
exceed twice the other.
(g) A duct must be so installed that
ordinary collection of water in the
bilge will not block vapor flow.
(h) A duct must be of rigid permanent
construction, which does not
allow any appreciable vapor flow except
through normal openings, and
made of the same material as the hull
or of noncombustible material. The
duct must lead as directly as possible
from its intake opening to its terminus
and be securely fastened and supported.
(i) A supply duct must be provided at
its intake opening with a cowl or scoop
having a free area not less than twice
the required duct area. When the cowl
or scoop is screened, the mouth area
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Coast Guard, DHS § 182.465
must be increased to compensate for
the area of the screen wire. A cowl or
scoop must be kept open at all times
except when the weather is such as to
endanger the vessel if the openings are
not temporarily closed.
(j) Dampers may not be fitted in a
supply duct.
(k) A duct opening may not be located
where the natural flow of air is
unduly obstructed, adjacent to possible
sources of vapor ignition, or where exhaust
air may be taken into a supply
duct.
(l) Provision must be made for closing
all supply duct cowls or scoops and
exhaust duct discharge openings for a
space protected by a fixed gas extinguishing
system. All closure devices
must be readily available and mounted
in the vicinity of the vent.
(m) A vessel of not more than 19.8
meters (65 feet) in length carrying not
more than 12 passengers, with ventilation
installations in accordance with
ABYC Project H–2, ‘‘Ventilation of
Boats Using Gasoline,’’ or 33 CFR 183,
subpart K, ‘‘Ventilation,’’ will be considered
as meeting the requirements of
this section.
[CGD 85–080, 61 FR 986, Jan. 10, 1996, as
amended by CGD 97–057, 62 FR 51050, Sept. 30,
1997]
"
Guy
:baby:. Or maybe not...
:sex::woot:
