Bilge Safety

[High Hopes]

Oh yeah. . . that little screw that holds the top down and secured to the basin. Mike, I wonder where I put that.

Basically, three ell shaped flanges welded to the basin bottom hold the canisters centered under the burner openings. Under the canisters are finger springs spot welded to the basin and they push the canister up against the bottom of the burner opening.

I have seen the canister escape from the three centering clips. But maybe this is because the top of the stove was not secured down onto the stove. (Duh) This seems reasonable as the springs, which push the canister up, also push up on the stove top, letting the canisters rise above the top of the clips. I will check this out.

Steve

[lat 64]

Hi guys.
I too run the blower all the time when running the motor.
You've all raised good points about getting better blowers and fire protection. I will probably look in to this more next spring.

I use about three to four gallons a year on my boat, and my fuel tank is old and probably full of poo. I am considering going to a much smaller day tank that is removable for the long time that I leave the boat unused in the slip. This means fresher gas, and not so big a fire hazard when I am not there. I don't cruise and if If I need more gas for an over-niter I might just have an extra can on deck.

The new day tank and filters would probably go in the huge gas locker in the laz that the PO installed for the propane. This locker is properly vented and all.

Cheers,

Russ

[rigspelt]

Gandalf's fire

Here's info on the fire Shawn mentioned:
http://www.anything-sailing.com/show...-Mackinac-Race
Speculation also in this thread:
http://forums.sailinganarchy.com/ind...pic=93960&st=0

[keelcooler]

A safe gas system

Dear a4 friends, I have preformed hundreds of cause and origin investigations on boat fires through the years and can assure you there are common themes when it comes gas engine boat fires. Gas motors are safe as long as all related systems are properly installed and maintained. Also a responsible owner must follow common sense precautions. I believe if the following precautions are religiously followed boating w/ our a4’s will be completely safe.


Get intimate w/ and know your fuel system from top to bottom. Inspect often and provide good access. Our components are old, they live in a hostile salt air environment, old stuff just fails. Take care of it before it does and always have your antenna up looking for those beginning signs of a problem.

If you smell gas there are explosive fumes aboard. You must act accordingly and locate the source. Gas evaporates very quickly and those fumes travel down. They will puddle in a low spots and hang. The blower induction hose end is down low in the bilge as required. If fumes are hanging under the tank, vent line or fill your blower is just not going to evacuate them. That’s why most explosions occur after refueling even when the blower was run an extended period of time before cranking. Surprisingly this type of fume explosion rarely results in a fire. No raw fuel, just explosive gas lighting off. After refueling open the lockers above or adjacent the tank, fill and vent lines. Vent and check for fumes every time. If this is not part of your refueling procedure make it so.

We all run our blowers and sniff the motor box/bilge areas before we start. Turn off the fuel feed after use. This is the no brainer procedure I hope everyone follows.

Make sure that all your systems are in compliance w/ USCG/ABYC codes. You must have the proper no more than 4 PSI marine electric fuel pump, not that NAPA auto pump that looks the same and pumps out 10 PSI plus. You must use an oil pressure safety switch (this is a biggie). I know it works fine w/out it but it’s required for a reason. Go through your bilge/motor box/fuel tank compartments and confirm all electrical goodies are spark resistant marine rated.

Done any mods? Is that AC/DC refrigerator you installed sticking into the engine space. Yes it’s marine rated but is it spark resistant? Likely not. Got some old stuff in there from the 60’s or 70’s like that original blower or charger. Think it’s still spark resistant? By the way unless it’s vapor proof it’s not 100% safe. No vapor proof electrical stuff sold at west marine except that propane solenoid switch. In fact you should assume you are going to have a spark once in a while, because you will.

Think running that 50 buck blower all the time is good? Don’t let that give you a false sense of security. In fact it can over heat and start a fire in the plastic squirrel cage housing. It’s just not made to run more than 10 minutes tops before being allowed to cool down. When you get them that hot how long do you think that thin plastic internal spark resistant shielding is going to last and not deform. This is one device you do not want to spit a spark.

[Mark S]

In fact you should assume you are going to have a spark once in a while, because you will.

Keel,

Can you recommend a blower suitable for continuous use, or at least describe the specs of such a blower?

Mark

[sastanley]

blower hose extension

keelcooler - thanks for bringing this thread back up.

After this discussion last year, and subsequent thoughts on my own, I have extended my bilge blower hose all the way to the bilge, in front of the motor, just above where it might get wet from sloshing bilge water. The old hoses terminated under the stairs at the termination of the quarterberth bulkhead, and were laying 'in the bilge area', but technically were no where near the low part of the bilge where fuel vapors would likely hang out.

The blower itself has to work a little bit harder now, but I can feel the blower sucking out thru the extended hose at the bilge since the end is now accessible and not under some cabinetry 5 feet away...this is also a good test when I stick my nose down there for a sniff test that it is actually sucking air...the discharge hose at the cowl vent likes to fill up with rain water and even though the blower is running, no air is actually being evacuated...so I have to empty that once a season or so. Now I know the blower is actually working since I have access to both ends.

[rigspelt]

Keelcooler, that's the best post I've ever seen on the topic. Good reminders to us all.

[keelcooler]

Mark, Best price I could find Jamestown distributors ITT Jabsco # ITT357600092, flange mount model. These are not on the shelf at west marine. Dave has a continuous duty model and may have a better source. They can move some air… put on an extension like Shawn and it can double as a central vac system.

Continuous duty blowers are available for just under $300. You mostly see this model blower serving a motor generator box/soundshield. A good blower venting your box all the time is good. A hot cheep blower running all the time is bad.

Most of our boats have 3" blower systems. All heavy duty blowers are 4" and will require 12 amp draw. If you upgrade make sure your wiring can handle and install 15 amp fusing.

[rigspelt]

All heavy duty blowers are 4" and will require 12 amp draw.

That, the weight and the noise are downsides in small sailboats. What does a continuous 12 amp draw do to fuel consumption and alternator wear?

[keelcooler]

The big boy blowers are just not practical for our boats. Power demands and cost alone take it right off the table. I for one see no benefit except may be keeping the cabin a little bit cooler. I’ll just open the forward hatch and ports thank you. Seems like a fool’s game to think it adds safety to our fuel systems. At worst it may even mask a leak/fume problem. To get the additional air movement benefit you need to fit 4” cowlings. My 3” take most of the rear deck as it is…I’m not cutting in any man holes in my deck. Did I mention the noise and vibration? Dave found it necessary to install shock mounts. On this one, lots of cons and few if any pros.

Just operate your blower as instructed by the builder and turn it off after starting. Millions of gas boat owners do it safely every weekend. Bilge and fuel safety is all about system knowledge and proper preventive maintenance. If your thinking safety enhancements spend the money on a fume detector, CO detector and auto haylon.

[hanleyclifford]

I second the motion on the automatic extinguisher in the engine room, not required by the Coast Guard but a huge safety upgrade. As for the 12 amp draw, according to Don Moyer's information that would be slightly less than 1/2 horsepower. Additional alternator wear would be negligible.

[joe_db]

I recently found out my FILL HOSE was leaking. That isn't something that get checked all that often. It was also dropping rubber bits into the tank, which I suspect might still be the cause of some of my fuel feed issues.
As for automatic extinguishers, I don't see how they would help a fuel explosion. When they go off, it is already too late
That said, I do have one.

[hanleyclifford]

I guess the logic behind the automatic fire extinguisher in the engine room is that since you have to have 2 B-5 units anyway, why not put one of them in the place where it is likely to do some good in the event? But in addition I carry an additional 2 B-5 units. After all, as the fishermen say, "...if enough is enough, more is better!"

[ndutton]

I wanted to address something Dave mentioned, the fume sniffer. Strangely I don't see it talked up much on this site, a site involving gasoline in boats. Xintrex makes models that simply alarm audibly and models that automatically activate the bilge blower in addition to the alarm. I have the latter.

As effective as the halon systems are, Joe's remark that they engage after it's too late is well made. Also, properly installed, the halon systems shut down the blower so as not to ventilate a fire and exhaust the halon.

The fume sniffer is intended to either alert you or exhaust the dangerous fumes before the worst happens. On another thread I told the tale of fumbling my fuel filter upside down in the bilge and the Xintrex system alarmed and activated the blower automatically within seconds.

I'm thinking a combination of the sniffer and automatic halon systems would be the best of both worlds.

[JOHN COOKSON]

Easy Blower Test

A few years ago, on a whim, I turned the blower on and then went to the bilge and put my hand over the end of the tube. I didn't feel any air being pulled by. When I blocked the end of the tube entirely the blower motor did not lug down or change in pitch.

I found a large hole in the tube right up next to the blower motor.

TRUE GRIT