Bilge blower / Vent fan

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DJGibbs
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Joined: Thu Aug 06, 2020 5:59 pm
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Bilge blower / Vent fan

Post by DJGibbs »

Are any Albatross owners using a bilge blower / vent fan? If so I would be very grateful of a photo of the installation.

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solitaire
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Location: Cheselbourne - Nr Dorchester

Re: Bilge blower / Vent fan

Post by solitaire »

Congratulations on your decision to install an extract fan to your inboard petrol engine’d boat, I have not installed one in an Abatross but probably over 50 installations in other small and medium boats during my 60 plus years in the marine business, Many have been for owners wanting to get a UK boat safety certificate.
In my opinion a “car engine” with a side draft carburettor, unless fitted to the UK boat safety or USCG (U S. Coast Guard) regulations has no place on an inboard petrol engine boat! Ah “ The Nanny State” you may say, side-draft carb’s can leak, float bowls can flood, which fine on a car, (it drips on the road) but on your boat, the vapour remains in the bilge until you ignite it with: - poor plug leads – non marine starters , dynamos, alternators, whatever automotive, non spark proof kit that lurks in your engine bay.
Luckily UK Boat Safety and USCG regulations (available on the web) explain how to minimise the risk of explosion with these side draft installations, Volvo Penta went as far as to ditch the side drafts and move to down drafts with no loss of power, and most US engine are a V configurations and only leak into the intake plenum.
Two essentials are:-
1. A shallow tray under the carb’s fitted with a flame proof gauze to catch petrol drips and leaks, (must also have a tap to drain off the fuel)
2. A flame trap on the carburettor air intake.
I always install a quality spark resistant marine extract fan like from a good supplier (like Vetus,or Whale), high in the engine bay, and use a fire retardant hose secured with jubilee clips (not tie wraps) to the lowest point fuel may accumulate in the bilge (just make sure the fan will not suck water). Inlet air needs to come into the engine bay high up, (no hose is necessary). If you can find one, (I think Aquafax sell as part of their Blue Sea range) A US style marine ignition switch has a “Fan on” position prior to Ignition and Start positions. I f you can’t get one, a “Run Blower before starting engine” sign on the dashboard will do.
You can also, (recommended) open the hatch and look and see (and sniff) but that may not be enough to detect vapour deep in the bilge.
If you have read all of the above – thank you, I have seen boats that have blown up (launches and cabin cruisers on the Thames and Italian Exotica hidden behind Mediterranean boatyards), they usually burn right down to the waterline.
A Boat owner is the “skipper” or “captain” of his boat – no matter how big or small the vessel may be, therefore totally responsible for its seaworthiness and the safety and lives of everyone on board.

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