Bilge Fan - Suck or Blow?

[JoeC]

One of the previous boat owners fitted a small extractor fan in the floor at the bottom of the electrical cupboard which is blowing air into the bilge. I am going to replace it with a quiet and energy efficient computer fan but is it better to blow or suck (behave yourselves!).

 

The only other hole I am aware of in the floor are two holes at the back of the fridge for cooling - the fridge is halfway down a 60 feet boat.

 

Thanks.

[Tam & Di]

I think it would create a more general flow of air if it is set to suck - inlet air will then come from whatever cracks in the flooring where it can.

[robtheplod]

I'd always recommend suck personally....

[ditchcrawler]

26 minutes ago, JoeC said:

One of the previous boat owners fitted a small extractor fan in the floor at the bottom of the electrical cupboard which is blowing air into the bilge. I am going to replace it with a quiet and energy efficient computer fan but is it better to blow or suck (behave yourselves!).

 

The only other hole I am aware of in the floor are two holes at the back of the fridge for cooling - the fridge is halfway down a 60 feet boat.

 

Thanks.

Was it intended to cool the Electrical cupboard the same as the ones to cool the back of the fridge ?

[JoeC]

6 minutes ago, ditchcrawler said:

Was it intended to cool the Electrical cupboard the same as the ones to cool the back of the fridge ?

That was my thoughts initially and I thought sucking the cooler air from the bilge into the cupboard would have done that. The cupboard does have an air vent for outside fresh air and a vent in the front of the lower cupboard door.

[Alan de Enfield]

42 minutes ago, JoeC said:

...........is it better to blow or suck

 

 

 

 

 

A 'proper' bilge blower (which I don't think you are talking about) sucks the engine / fuel fumes out if the bilges and blows them down a pipe to the 'outside' before the engine is started.

Edited August 27 by Alan de Enfield

[1st ade]

39 minutes ago, Alan de Enfield said:

 

 

 

 

 

A 'proper' bilge blower (which I don't think you are talking about) sucks the engine / fuel fumes out if the bilges and blows them down a pipe to the 'outside' before the engine is started.

I was always told (urban legend?) that it was a bilge blower so the motor and fan were not working in fuel fumes - suck in clean air and clean the bilge rather than extract fuel (especially petrol) fumes past a brushed motor... With the potential for "Bang"

[Alan de Enfield]

1 hour ago, 1st ade said:

I was always told (urban legend?) that it was a bilge blower so the motor and fan were not working in fuel fumes - suck in clean air and clean the bilge rather than extract fuel (especially petrol) fumes past a brushed motor... With the potential for "Bang"

 

 

Well, going by mine (I have one over each engine) it 'sucks' the polluted air from the right hand side and blows it out and into the pipe connected  to the outside air (left hand side) and where it fits into the pipe you can see the arrow showing the direction of flow and how to install the 'blower'.

 

 

[1st ade]

4 minutes ago, Alan de Enfield said:

Well, going by mine (I have one over each engine)

I did say "urban legend"? I can think of other reasons (brushless motors?) why all bets are off, never mind my wild guess's!

[MtB]

2 hours ago, ditchcrawler said:

Was it intended to cool the Electrical cupboard the same as the ones to cool the back of the fridge ?

 

Frankly if the electric cupboard is getting hot to the degree it needs fan cooling, there is something badly wrong in there.

 

 

[JoeC]

I bought a PC fan (Noctua NF_S12B Redux 1200) fan from Ebay and installed it to BLOW into the bilge.