Adding a fuel tank

[FourPoints]

My outboard has a small 3gal tank under a hinged deck plate in the cockpit for easy access and refilling. Since it only holds 3 gal, it is only enough to motor for about 6hrs at a little over 5kts (in flat water), or 7-8hrs at 4kts.

I would like to add a more permenent fuel tank around 8-10 gallons, and I am wondering A) what safety considerations do I need to be aware of for installing a gasoline tank, B) where is a good place to buy small gasoline tanks for permenent mounting, C) are there any cheap fuel level sensors that will communicate with my Garmin chart plotter?

 

[Winkfish]

What about getting a larger plastic tank - 6 or 12 gallons? My Whaler came with 2 12gal plastic tanks, with the lines running from the tanks to the motor under the deck. They're easy to deal with, and you don't have many of the problems metal and fiberglass tanks can have, especially with ethanol fuel.

 

[FourPoints]

If you mean just a larger portable tank, the space the current tank is in was designed specifically to fit this 3 gal steel tank, or the tank was designed to fit the space, not sure, either way I cannot even find a 3gal plastic tank that fits the space, and nothing larger than 3.5gal could even be made to fit there, so my only alternative is a larger tank installed somewhere else in the boat.

I don't have any preference of any particular tank material, but plastic does seem to be the easiest / lowest maintenance. Whatever I install I want to have a deck fitting for filling, and some sort of way to monitor the fuel level, ideally in a way that integrates into my garmin as I can set an alarm for fuel level on there, and that is on 99.9% of the time the engine is runnning

 

[Winkfish]

That is what I was talking about. I understand about the space limitations. As for plastic, I remember Peggy talking about a company that makes custom plastic tanks - I'd imagine they could make it out of "fuel-capable" plastic as well. I wouldn't think deck fittings, or any kind of fittings, would be any more a problem for plastic than for other materials.

As for tank vs space size, where is your current "space"? Can it be modified/enlarged?

 

[mitiempo]

Here's a link to Moeller plastic fuel tanks in many sizes.
http://www.moellermarine.com/aftermarket/fuel_storage_tanks

 

[FourPoints]

I checked the website for the company peggy is always mentioning, and they gave no indication that it was safe for fuel. As for modifying the existing space, it is molded into the cockpit deck, so no chance of modifying that.

The moeller 12gal may work, it's little bigger than I was looking for, but having a little extra fuel onboard isn't a bad thing! I need to get down into the lazerette and do some serious measuring to see what I can fit where.

 

[CalebD]

FourPoints,

If you go with a more permanently installed tank of @ 10 gals mounted somewhere below the cockpit you will need to add a vent line for the tank and through hull fitting for the vent above the water line (transom works well for this). It is not good to vent fuel tanks or Gerry cans directly into your cabin for obvious reasons. ABYC has a bit to say on this topic.
If your new tank is mounted below your cockpit floor I also wonder about your outboard fuel pumps ability to create enough 'head' to get the fuel flowing smoothly. You might need to add a fuel pump bulb near the tank to prime the line like you probably have on your 3 gal. tank.
As for fuel level sensors I can't help you - we use a stick to measure our tank level through the main fill - I doubt the stick can tell a Garmin anything!

 

[Steve Dion]

You need different models for above deck/below deck tanks. Once you decide where the tank will be you should be able to find a suitable size.

You want to be sure that you have proper ventilation and a vent if you are below deck. That may include a fan to exhaust any fumes that may collect in the bilge and/or the compartment where the tank would be installed.

 

[mitiempo]

Your insurance company will have a bit to say as well. I wouldn't install a fuel bulb on a gasoline tank below decks. In a cockpit locker that is vented it is different.
If you are not burying the tank out of sight you may be able to determine fuel level visually if the tank is translucent and not red.

 

[FourPoints]

The only choices for space will require the tank be fairly hard to check visually, but due to placement the biggest lift possible from the tank to the engine would only be about 12 inches or less, so I don't think a fuel pump would be necessary. As for installing the primer bulb below deck, I wasn't planning on it. I beleive I could run the line in such a way that I could easily get to the primer bulb.

I don't think the insurance company ever asked me about fuel capacity or tank type, but I think they would prefer the permenant tank over storeing the jerry can in the head when I'm not at the boat...

Do I need a blower fan for a tank installed in the lazerette, if I install a proper vent line near the stern?

 

[Steve Dion]

The tank will emit fumes. The fumes are heavier than air. If the tank is in the lazarette it is essentially inside your boat and you should have a blower to evacuate the fumes.

Be sure that you get a tank that is rated for GASOLINE. Different stuff than water tanks (still poly).

 

[Ron20324]

I'm pretty sure the Coast Guard prohibits putting gas into any area that can have passage of fumes into the living area. So I would say, NO, to any lazz installation unless it is totally sealed to itself- and still vented.

 

[kloudie1]

It is OK to do that in the lazarette but it has to be done correctly.. Deck fill and overboard vent.. Brass fittings.. shut off valve on tank.. and if gasoline, ya must have a bilge bower for ventilation..marine rated fuel lines.. Most states have a law (along with Coast Guard) that the blower has to be run for 4 minutes minimum after a fill up and before the engine is started.. The blower intake has to be low in the boat.. Not sure of exact wording, but if you look in your state Wildlife/Fisheries boating regulations, you'll find it..
Check out what West says:
http://www.westmarine.com/webapp/wc...51&catalogId=10001&page=Fuel-System-Checklist

 

[Manny]

6 hrs at 5 knots from 3 gallons?

You must have a pretty efficient outboard, my Honda 9.9 burns about .8 gallons an hour at 5 knots. But it's pushing an estimated 8k pounds and I have a very low pitch prop. Anyway, I don't have a dedicated fuel lazarette, and I wanted more range so I decided to free up cockpit space by hanging a 6 gallon tank on the stern railing. I made a harness for the tank with rings, it clips on to the rail and it has worked well. I can remove the tank in less than a minute to take to the gas station for a fill up. Checking the fuel level is simple, I just turn around... No problems in rough weather either.

You can see part of the tank on the right side of the picture.

M