Proper way to place engine compartment/bilge fans?

[pachanga58]

1989 Sea Ray Pachanga 27 Sport Cruiser. Twin engine. Over time, the fans and vent hoses in the bilge need to be replaced. What is the preferred or the correct way to place new fans and vent hoses? Fresh air intake on one side (port side) and exhaust air on the other side (starboard)? Currently two fans, however, I am thinking four fans with the idea to really purge the bilge area before a start. Where should the intake end of the hoses be placed? One low between the engines and one placed in front of the engines about carb level? Exhaust ends feed the external engine bilge vents. My owners manual does not specify location. The boat does not have the louvered vents with the directional air flow scoops. the vents are covered.

 

[Lou C]

Here's the official word from Chapman's....I have mine set up that way because I have vents that are directional and I have one facing forward (fresh air intake) and the other facing rearward (connected to the blower).
I also installed a gas fume vapor detector to make me aware of a leak if it happens underway. Always check for fumes before starting or even switching on the blower....

 

[pachanga58]

Here's the official word from Chapman's....I have mine set up that way because I have vents that are directional and I have one facing forward (fresh air intake) and the other facing rearward (connected to the blower).
I also installed a gas fume vapor detector to make me aware of a leak if it happens underway. Always check for fumes before starting or even switching on the blower....

Thanks - that works! I do open the engine bay hatch before every start - if only to open it 6 inches to allow for some fresh air.

 

[mr 88]

Fumes are heavier than air and drop to the lowest point in the bilge . That's where your discharge hoses should be , under the engine or facing the oil pan. The inlet fresh air hoses do not need nor should they have blowers attached to them . They can terminate at a higher level but don't have to be facing the air intake on the engine .

 

[Lou C]

I can’t tell you how many times I’ve been at the gas dock and see people with inboards & I/Os just start up after fueling no sniffing to make sure there isn’t a gas leak. Your nose is actually more sensitive than a gas vapor fume detector…

 

[QBhoy]

Down low.

 

[Drcoffee]

In my Rinker captiva the blower is mounted on the stern with the intake hose hanging into the bilge area, and the fumes vent out the back over the swim deck. The fresh air flows in from the cavities in both sidewalls left and right. There’s No need for a special inlet vent.