# Mount above-deck gas tank below-deck?



## bajaking (Jun 6, 2013)

On a new-to-me Cal 27, the p.o. installed an outboard engine to keep sailing despite a dead inboard (which I intend to remove). He just kept the gas tank sitting on the cockpit floor full time. Needless to say, I find this arrangement dissatisfying. Long term, I'll probably install a new diesel or an electric, but for now, the outboard stays. 

Is it a horrible idea to move the gas tank below deck? I mean, yes, it's a horrible idea, but just how horrible? If I install a vent hose on the tank that runs to an outlet on the transom, and run the fuel line through the transom to the engine, is that really any different from a standard belowdeck setup? I can use the old engine blower to vent the bilge and will be removing the tank when I fill it. I'd rather not invest the money & effort for a "proper" belowdeck fuel tank and deck fill and fuel gauge and all that goes with it, just to remove it all in a couple years anyway. Engine use is just in-out of the slip and occasional no-wind get-home-faster trips of an hour max. 
I also don't want an early, fiery death.

As a reference point, on my Santana 22, the 6 gal "above deck" style gas tank for the outboard was stored on a platform inside the lazarette full time, even when in use. Boat didn't blow up. Granted, a full bulkhead separated the lazarette from the cabin (although the lazarette was probably 25% of the boat's volume). All Santanas have the same setup, and no one has made issue of it. Probably many other small boats do the same.

My only other option is to mount it on the pushpit, which offers its own set of problems.
Anyone have ideas or suggestions?


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## PaulinVictoria (Aug 23, 2009)

Can the outboard suck up the fuel from below decks?


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## paulk (Jun 2, 2000)

Does the bilge ventilator fan still work? Wouldn't want a spark from the new fuel pump you'll probably need to install to ignite the fumes in the bilge. Celebrating the Fourth of July on launch day is generally frowned upon. This is one reason people use diesels, and keep outboard fuel on deck, outside the cabin.


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## tommays (Sep 9, 2008)

It is a good bit of work and a good bit of money to install a SAFE below deck fuel tank

On my smaller J24 a strap and some fittings kept the tank in place above deck without issue for 30 something years


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## JoeLena (May 14, 2012)

paulk said:


> Does the bilge ventilator fan still work?


In the OP he says it does.

There are newer vent-less outboard tanks that seem to work. While testing my A4 I used one in the aft lazarette. The compartment was already wet and vented, and I had no issues with fuel but it was above the inboard. I did replace the permanent tank before long.

You would not need a gauge since you use it so little, but the one I had did sport a gauge on top.

Would seem that is mounted high enough it would still be above the engine. It is your boat and responsibility so whatever makes you feel safest. The hysteria over using gas instead of diesel is just that. Gas has been used a long time, on a lot of vessels without issue.


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## bajaking (Jun 6, 2013)

Thanks for the input, folks. I don't think fuel delivery will be an issue since I would install it at about the same height it is now, just on the other side (inside) of the cockpit wall. But I am paranoid about having gas belowdecks, especially given the poor construction of current portable tanks. I have more thinking to do. Maybe I'll just get a smaller (2-3 gallon) tank and mount it on the pushpit so it's out of the way.

Does anyone know how similar sized boats with factory outboard options are set up (e.g. Catalina 27, Ericson 27)? Do they have fully "compliant" belowdeck tank installations? I'm guessing a portable tank in a separate, enclosed well? Hmm...maybe I could go that route. Just a little plywood & glass.


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## bajaking (Jun 6, 2013)

I see the Catalina 27 has a large, proper lazarette (my Cal 2-27 cockpit runs right to the transom). The 4th pic at the listing below shows a portable tank in the lazarette with a couple of vent hoses. Can any Cat 27 owners confirm if this locker is completely sealed off from the rest of the boat?

1984 Catalina 27 Sail Boat For Sale - www.yachtworld.com


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## svHyLyte (Nov 13, 2008)

bajaking said:


> Thanks for the input, folks. ...But I am paranoid about having gas belowdecks, especially given the poor construction of current portable tanks. I have more thinking to do. ....


Why not simply use a 6 gallon transom mount tank, hanging on the outside of your transom? You could add a pad-eye along the center-line of the transom just below the bottom and another above the top of the cross piece of the tank to fully secure it in place even though the hanging brackets would take the weight of the thing. For example:










That would solve your problem with less chance of blowing-up/burning down your boat.

FWIW...


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## miatapaul (Dec 15, 2006)

JoeLena said:


> The hysteria over using gas instead of diesel is just that. Gas has been used a long time, on a lot of vessels without issue.


Well I agree and disagree with this statement. Yes gas can be perfectly safe, if installed in a safe manor, with proper ventilation. But diesel is inherently safer by a large margin than gas. Gas has a very low flashpoint and if not properly vented fumes can pool and explode. diesel on the other hand has a much higher flashpoint and does not create explosive vapors at normal boat temperatures. It basically has to be squirted out of a fine jet to atomize it enough to be flammable. You can drop a lit match into a cup of diesel and the match will go out, not so with gas. So I don't think it is hysteria at all, just that a proper system must be maintained for gas to be safe. Some know that many will not maintain the systems well so recommend diesel instead. Same thing is true of propane, yes it is in fact more dangerous than CNG but as long as you have the proper systems and they are maintained then it is fine.

The bottom line is if you are moving a gas tank below decks you have to make sure the compartment is sealed from the rest of the cabin, and that there is proper ventilation even with a non-vented tank.

Seems to me that a boat like this is likely going to only need a small amount of fuel to have sufficient range, I would get the smallest tank I could find and install it on the stern rail, somehow. If you are going to go cruising for a longer time then you could always put a jerry can on deck. This would get the can out of the cockpit, and the smaller tank would encourage the use of FRESH gas since today's gas is only good for a few weeks at best before you wind up with carburetor issues anyway. The other thing to look into is if it had an A4 (or other gas engine) originally where is the original tank, and if it is sound perhaps you could use that and add a small electric fuel pump inline.


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## svHyLyte (Nov 13, 2008)

For the sake of the exercise:


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## bajaking (Jun 6, 2013)

The more I think about it, the less I'm inclined to move the tank below deck. The cabin is currently clean and odor free, and bilge is clean and dry as a bone, and I'd like things to stay that way.
HyLyte -- I didn't know such tanks existed. Thanks for pointing that out, and going to the effort of photoshopping one on a Cal! I think I may just go that route. There's little room to work with for setting up a standard boxy tank in the aft cockpit/transom/taffrail area, so that odd tank may be just the ticket. I can make a canvas cover to reduce the ugly factor and provide some sun protection.


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## svHyLyte (Nov 13, 2008)

You don't need to make a cover. Just paint the tank (leaving the top surfaces red). The portion that crosses the shear strip can be painted "Pepsi Blue" (I assume that's the color of yours as it was the most common on Cal's) and the lower portion white to blend in with the hull. Just use a plastic primer and then a common semi-gloss latex paint. It won't last forever but it will several years at a time and certainly until you get your inboard replaced. And, the tank can later be used for your dinghy, eh?

Good Luck...


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## bajaking (Jun 6, 2013)

Mine has the "vomit red" stripe.
Now, if I can only find out where to buy one of these tanks. There's a 6 gallon on ebay for $200. I notice the Moeller site says "approved for use in Australia, New Zealand, Japan". I wonder what that's about.


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## azguy (Jul 17, 2012)

I think if you ran a vent hose you have no problem at all. I'd rather not have that tank mounted on my stern.


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## mitchbrown (Jan 21, 2009)

Maybe I missed something here but couldn't you use the existing fuel tank. Just suck out the diesel or whatever is in it and fill it with fresh gas. Run a hose to the outboard and bingo!! all done. It must have a tank if it has an inboard.


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## svHyLyte (Nov 13, 2008)

bajaking said:


> Mine has the "vomit red" stripe.
> Now, if I can only find out where to buy one of these tanks. There's a 6 gallon on ebay for $200. I notice the Moeller site says "approved for use in Australia, New Zealand, Japan". I wonder what that's about.


Humm...

A quick search reveals these units still being offered by Budget Marine in Martinique but no longer offered by either Defender or West Marine or other state-side vendors (of which I was not aware when I offered my suggestion and for which I have no explanation). Other than the used equipment-market, state-side, I don't see many economic solutions to obtaining one. As a practical matter, if you have some building/fabrication skills, you could make up a small platform that your could temporarily hang on your transom to secure a 3-gallon tank to while you were sailing/under-way (but storing them in the ****-pit while you're away from/off the boat). In any case, I would not succumb to the temptation to temporarily mount an outboard tank below deck, elongated vent tube or not.

FWIW...


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## bajaking (Jun 6, 2013)

mitchbrown said:


> Maybe I missed something here but couldn't you use the existing fuel tank. Just suck out the diesel or whatever is in it and fill it with fresh gas. Run a hose to the outboard and bingo!! all done. It must have a tank if it has an inboard.


I considered that for a minute, but I can't imagine what's inside the tank. Engine seized at least 5 years ago, per p.o., so I suspect there's some 5 year old diesel in there. The tank exterior and its connecting hoses are all sketchy looking. Disposal of the tank is one of my next projects.

I will probably end up just mounting a 3 gallon tank on a small platform atop the transom. Or do nothing and live with it in the cockpit. Oh well. Shame those dinghymates aren't available.


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## mitiempo (Sep 19, 2008)

azguy said:


> I think if you ran a vent hose you have no problem at all. I'd rather not have that tank mounted on my stern.


The fuel fill cannot be below deck. It is both an ABYC and Coast Guard regulation - eg a law.

If there was a fire I doubt your insurance would pay out either.


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