Bilge Fans - independent or ganged

[bud37]

Sorry I don't have any specific knowledge of your particular boat but there are general rules for this. One thing I would check is to follow the existing blower out hoses to the exhaust outlet fittings ....you are right, there should be another hose coming back in from one side that has fresh air to dilute the bilge. Look to see what is connected up there if you can. So if you have four is there two for in and two for out?

It is not unusual for those hoses to get severed over time as they get brittle and get stepped on. Hopefully someone with the same model as yours that is still original can chime in.

[Cooler]

As I understand your description, the logistics are normal. The 2 output hoses are to evacuate the "potential" contaminated air. The air vacuum hoses or intake, would serve to collect contaminated air surrounding the engine area. The blowers do not come on automatically with ignition. That would be too late if there are fuel fumes in the engine area. Different switch light colors serve to let you know which switch has been manually turned on. Sounds like all is correct from the factory, but as Bud says, check those hoses for any cracks or tears. They are not typical dryer hose, they are made for marine application. er

[km1125]

I would think they would all connect to hoses to exhaust the bilge air outside the hull, but this is the first time I'm hearing a boat that size have four blowers.

Do the 'inboard' blower hoses both go to the same side of the boat?

[Alanna Mo Cree]

My 360SS has all four bilge blowers going to the vents outside the hull, two on port and two on starboard. The furthest outboard hoses are not connected to the blowers and I believe are for the batteries to vent.

Switch operation is the same as Cooler indicated.

This image is the port side showing the two hoses going up and the third hose barely visible.

PXL_20230701_183304086.jpg

[km1125]

QR_BBPOST My 360SS has all four bilge blowers going to the vents outside the hull, two on port and two on starboard. ...

Curious what the vents look like on that model.

On many models the vents are arranged so they pull in air on one side of the boat and exhaust it on the other. If you look at their louvers one side is pointed forward and one side aft. This is so there's natural "flow-thru" ventilation while the boat is moving, even if the blowers are off.

I'm wondering if yours are arranged more forward and aft, whereas the forward ones would pull in air and the aft ones would discharge it (and where the blower hoses would be connected).

[bud37]

QR_BBPOST My 360SS has all four bilge blowers going to the vents outside the hull, two on port and two on starboard. The furthest outboard hoses are not connected to the blowers and I believe are for the batteries to vent.

So, if I understand you correctly there are two hoses on each side port and starboard connected to blowers which are evacuating air from the compartment and one hose allowing air back in on each side ? Yes

Is there any other fresh air venting for the engine compartment, just curious. Not saying you have an issue, would be nice to hear from someone that has the same boat as you.

Engines need fresh air to be efficient....fun fact, a running carbureted 454 will need around 75 CFM air at idle depending on the engine build ( efficiency)...up from there 1500rpm- 158 Cfm......3600rpm-378 Cfm....you can double that for two engines....all that air will to be pulled into the compartment and out the exhaust pipe by the engines alone.

[paulr]

So after reading all this, to start trouble shooting a 2001 396 gas that has I only 1 blower of 4 working, the process would be to: turn on on the helm blower switch, turn on the electrical panel blower switch in the solon, then check to to see if there is 12 volts going in and coming out of the individual blower relays. If there is 12 volts coming out of the relay and the blower doesn't come on the blower is shot. If there is no voltage coming from the relay but voltage going to it, the relay is shot.
This whole thing is overly complicated to me. I guess it is that way so you can turn on all the blowers at the same time and turn all of them off at the same time. Do you think my logic is correct?

[bud37]

paulr....try checking and cleaning all the connection points first.

[paulr]

I thought that is what checking the voltage is all about.

[bud37]

QR_BBPOST I thought that is what checking the voltage is all about.

It was just a tip....sometimes that is all that is wrong. Good luck and get those blowers working to be safe.