How many bilge blowers should I have?

[mia9516]

Greetings all,

I have a 1989 Cobalt 192 Condurre with a 4.3 L Mercruiser Alpha One.

While out on the lake this weekend I noticed that the bilge blower may be about to call it quits on me. The reason I know this is because it's making a a high pitch whine while running and when I hit the switch to kill it, it sounds like it's grinding to a stop. I did a quick forum search and it looks like the bearings are shot. So with that being said, I will be replacing the blower before my next boating trip. After all, they are about $30 brand new anyhow. Small price to pay for safety, right? My question is the following:

How many blower fans should I have? I have four ventilation hoses in my engine bay, two on the port and two on the starboard side. The blower is located on the starboard side of the boat and the hose that is attached to it looks like it was cut in such a way as to draw in air from the vent and from the engine bay simultaneously. Not sure why though. Was the installation of four hoses overkill on the previous owner's part? I can't imagine it being like that from the manufacturer with only one fan installed. Would I be able to wire two fans to one circuit? Thanks.~Milt

 

[seabob4]

Re: How many bilge blowers should I have?

You're right about the bearings, that is typical of blower motors...

I'd recommend 2 on the exhaust side, with 2 separate feeds. Since you have 4 hoses, I have to think there was another blower in there at one time. You COULD run 2 off the same switch and appropriately sized breaker, but I don't think the wiring would be up to it...

 

[bruceb58]

Re: How many bilge blowers should I have?

No need for another blower and you don't want to add it to the remaining inlet hose. That is not to have a blower connected since that is the hose that draws fresh air into the bilge when you are underway.

 

[seabob4]

Re: How many bilge blowers should I have?

Bruce,
He has 2 "inlet" hoses on port, 2 "exhaust" hoses to starboard. It wouldn't hurt to have 3 "inlet" hoses, but I think the design calls for a second blower...

 

[bruceb58]

Re: How many bilge blowers should I have?

You need at least one inlet and one exhaust with nothing on it.

 

[seabob4]

Re: How many bilge blowers should I have?

You need at least one inlet and one exhaust with nothing on it.

Bruce,
Beg your pardon, but you need an exhaust with a blower, and an intake with nothing attached, must be located within the lower third of the bilge (ABYC). The bilge volume dictates the amount of air that must be recirculated. This can be achieved by any different types of configurations...

 

[bruceb58]

Re: How many bilge blowers should I have?

Just looked at my boat. There are two exhaust hoses...one of which has the blower inline. There are also two inlets for fresh air coming from forward facing vents on the side of the hull.

I don't have the rule in front of me but it just seems that if I had a blower in both of my exhaust lines and the blowers were off that not much air would go through. That just makes sense to me.

Unless I am completely wrong and the second hose is also an intake. Are you saying the intake also has to be in the lower 3rd of the bilge too?