Bilge Fans - independent or ganged

[CaptBob]

I had a bit of discussion with my fans this winter also. Changed my inline fans to squirrel cage blowers. (quieter) Turned into a bigger project, but in some twisted fashion, I enjoy this stuff. Two fan switches, helm and interior generator control panel. Either switch will turn the fans on, (provided the helm breakers are on) but can only be turned off by switch that activated them. Helm DC panel has 4 toggle/breaker switches. They are the power for the relays for the fans. There are individual relays for each fan. The switches on the dash and gen station turn on all the relays, the 4 breakers supply the power through the relay for each fan. The switches get their power (to activate the relays) from breaker #1.

So... The main on the helm DC panel must on, then fan one must be on, then each of the other three can be controlled individually with the breakers. Why? I dunno. I just leave them all on all the time and hit the helm/gen switch to control them. As we run our genny pretty much all the time, I leave the blowers on from dock to dock.

[Peter]

Uummm i will have to play with my switches as various blowers dont seem to work but it may be im not switching stuff right reading the above !
The generator fan that switches from the lazorrette panel doesnt seem to work now any ideas ?

[Tomion]

It is my understanding with engines running the blowers are always on to provide cool air to engines and keep the engine compartment cool. Is my understanding correct?

2001 Carver 444

[Keith S]

Basic blower stuff.
Diesel boats do not require blowers to remove fumes, the blowers are used to control engine compartment temperature.
Therefore they usually draw air from the upper 1/3 of the compartment and may be controlled by a thermostat in the engine compartment. If a fire extinguishing system is installed, a means to shut down the blowers when the fire system activates must be installed.
Gasoline powered boats require the blowers to remove combustible fumes from the bilge. The blower intake must be in the lower 1/3 of the compartment but above the normal level of accumulated bilge water.
ABYC H2 specifies one blower per engine located as close as possible to the engine is serves. Multiple blowers must operate simultaneously with each blower provided with it's own over-current protection. Blowers must have a visual indicator other than switch position such as a light. H2 is 13 pages of more than you ever wanted to know about bilge blowers.

[mjmason1]

I had to replace all of my blowers this year. Actually some of them haven't worked since I bought the boat. In the process we removed the relays. They didn't work either. I have stickers on both helms to remind me to turn on the blowers. Unfortunately the breakers are in the master stateroom. Kind of a pain, but at least they work. It sounds like a jet engine when they are on!

[Sgodfrey]

I have a voyager 450. Blowers don’t work. Are the relays next to the blower motor ? I am assuming you just removed the relay and wired directly to breaker ?

[Tireless]

This is an interesting subject. In my Carver 44, which is 396 with cockpit, I also have 4 breakers that control the bilge blowers. There is also a switch on the helm and the breaker panel, beside the genny switch, to turn them on as well. They come on automatically when the ignition is on.

However, one thing I did notice that was different than in all of my gas powered boats. The 2 blowers on the Starboard side blow air into the bilge and the 2 on the Port side blow air out, over the top of the engines. I was advised by mechanic, that this is to keep the air around the engine cool, clean in addition to removing fumes from combustion. So, if replacing blowers for any reason, be sure to install them the proper way.

Where as, with a gas engines the blowers draw air from down low in you bilge and exhaust them out of the boat for obvious reasons.

[gotjeepzj]

I want to replace this piston pump with a sump box, but also want to go ahead and install all new hoses. I can’t find where the shower discharge access is.

[buster53]

Obviously, it's going to be pretty close by, probably within a foot or two of the drain.
Carver is pretty good at hiding bilge access panels. Do you have carpeting on the floor just outside the head? If you do, try pulling it up, most likely, it is not glued down.

[mjk1040]

Our discharge was on the starboard side of the bow haul. Look under the mattress there should be access panels to the bow haul and you should see the thru haul and hoses. Ours had a shower sump, how ever I have heard of some that drained into the bilge and the bilge pump pumped the shower drain overboard.