Helm Blower Switch

[lehighsail]

I am thinking of installing a switch at the helm for the engine compartment blower just to make it more convenient rather than leaving the helm and going down to the main panel. I searched the modifications but see nothing there about it. I would just splice into the existing wire from the panel to the fan motor. Is there any reason not to do this? Does this need to be fused? Any particular type of switch? Thanks.

 

[SEMPERAVANTI41]

I was always surprised that the blower switch is not located at the helm and thought about moving it on other boats I have owned. Well on my new to me Hunter 50, it's located at the helm! Must say it really makes sense.
Wiring would be as you describe, I don't think a fuse is needed as the circuit will already have one. My boat has a rubber booted toggle switch.

 

[alexco38]

My engine blower comes on as long as the engine switch is ON. No need for a separate switch.

 

[capta]

I did the same thing for my running and spreader lights. Just as you said, break the line from the panel to the blower and add a switch. It should already be fused or have a circuit breaker.

 

[Ralph Johnstone]

I am thinking of installing a switch at the helm for the engine compartment blower just to make it more convenient rather than leaving the helm and going down to the main panel

I would think a take-off from either either the oil pressure line or ignition switch would be more "automatic" and one less thing to think about when leaving the dock. Attached is a wiring diagram for the fan I installed in mine a few years ago. I chose to take the signal off the oil pressure switch just to reduce the electrical load (all of 4 amps) on the battery at start up. Never can tell when you might need it. The electronic relay is necessary or otherwise the low oil pressure alarm will always be sounding. The voltage regulator is required to keep the fan from launching itself out the window when the alternator output hits 14.7V.

 

[capta]

Good day Ralph.
What program are you using to create the schematic above and can you attach meters, etc. to see loads, etc?
Thanks,
Andrew

 

[Ralph Johnstone]

Absolutely nothing so sophisticated. It's a program called SmartDraw. What I like about it is that it has a huge library of parts for the artistically impaired. All electrical measurements come off the back of a dirty dinner napkin.

It's about as high tech as I want to (need to) go after retiring.

 

[lehighsail]

Thanks to everyone for the information. I am probably going with just the plain rubber booted toggle switch as Capta agreed and Semperavanti suggested. I don't want to attach it to the oil or ignition because I usually run the blower for about 10 minutes after shutting down the engine , as suggested years ago by Mack Boring and I could not even begin to figure out the schematic from Ralph. LOL. Now I can''t wait for a cool rainy day.

 

[Ralph Johnstone]

I usually run the blower for about 10 minutes after shutting down the engine. I could not even begin to figure out the schematic from Ralph. LOL.

No wait, WAIT ! ! !

You could install a delayed OFF switch in that whole mess to really make things really interesting. I had thought about a delayed OFF switch in the circuitry but was concerned that there was always the possibility of the switch not functioning (for some unknown reason and unbeknown to me) and I stood the chance of running the batteries down when I was away from the boat for an extended period and not plugged in to shore power.

 

[wflowe2]

I thought that the engine blowers were for gas powered boats to vent engine compartment before starting and blowing up the boat. What is their function with a diesel powered boat?
What have I been missing ?

 

[Tally Ho]

I thought that the engine blowers were for gas powered boats to vent engine compartment before starting and blowing up the boat. What is their function with a diesel powered boat?
What have I been missing ?

Drawing heat out of the engine compartment mostly.

Greg

 

[Ralph Johnstone]

What have I been missing ?

My reason for installing a blower was to cool the engine compartment (like a Nike shoe box) in order to supply cooling air for the alternator. I had recently installed a Balmar external alternator regulator which really put the alternator to work. This heavy work load caused the alternator to quickly heat up, hence the need for cooler cooling air.

 

[AXEL]

My 2000 Catalina 30 MKIII has the blower switch at the helm. I little rubber booted toggle. Keeps the engine compartment cool and provides lots of fresh air for the engine to consume.

 

[Roadking Larry]

Mine was on/off at the main panel in the cabin when I got it. The wires to the blower motor itself ran 8" below the panel in the cockpit. easy mod to splice in for an added switch in the panel.
Added it when I replace the 39 year old crumbling plastic panel. Also added switches for the nav lights at the same time.

 

[seadaddler]

On a boat on salt water I always thought less is better and things are always getting
some kind of moisture on it sooner or later and than a bad connection.
When ever I get ready to go sailing and need to start the motor I also go to the main panel and flip on all my instruments and VHF and Blower and all my breakers are together.
Usually don't shut it off until we are all done and some times even leave it on a while longer if we are out anchoring for the night in hot weather.
After motoring I don't worry about battery power either so simple is better and less added wiring for the blower I think is better.
I just tell some one to shut the blower off if done motoring and start sailing.
Nick

 

[DougM]

The dinky little blower isn't going to do much to cool the engine, it just keeps air moving around the engine compartment and maybe supplies a small percentage of combustion air for the engine.
It might keep diesel odors from building up, but that's about all. On Beneteaus, the blower is wired to run when the instrument panel key is on.
I often wondered why there wasn't a separate air intake designed into the boat simply to provide combustion air to the engine.
There is no radiator, so the engine is totally reliant on the heat exchanger for cooling.

 

[lehighsail]

Again, thanks to all for the replies. I will be putting the toggle type in. It is really for convenience and so someone doesn't have to run below to turn off or on when needed. If the switch should corrode from the salt water, it would be easy enough to replace it at the helm. As a matter of fact I will put it on my maintenance list to check every year and replace every few years if necessary. When leaving the dock, final relaxation does not occur until the sound of the blower is off; just can't leave it on.

 

[Sandy Stone]

I often wondered why there wasn't a separate air intake designed into the boat simply to provide combustion air to the engine.

On my 375 there are two 4" flexible ducts from the transom into the engine compartment, and also two ingenious little vents on either side of the companionway. I'm surprised there isn't something similar on your boat.

 

[Ron20324]

[QUOTE...I often wondered why there wasn't a separate air intake designed into the boat simply to provide combustion air to the engine. QUOTE]

Doug, doesn't your B323 have an air vent on each side of the companionway, below the cabin-top winches? Like mine?

 

[lehighsail]

Are the air vent you refer to about 1" round? and have a little moveable wooden cover plate. If so I did not think of them as air vents but rather as a port for a fire extinguisher if needed.