Gas Tank Problem/Question

[snicklas]

I have a old boat that I just got, 16 foot Markum with 60 hp 1984 mercury outboard on it. It has a red 6 gallon tank sitting in the back compartment where the battery is. When I have seen these tanks in stores they were labeled topside use. Is this safe to have here, or should I buy one specifically designed for below. What is a good size to have, I am not sure how far you can go on 6 gallons. I am not racing all over the place, but do want to know I have enough gas.

Thanks,
Scott

 

[jtexas]

Re: Gas Tank Problem/Question

Is the compartment open to the atmosphere at least on one side? Your tank vent opens into the compartment, so you may have a bit of a hazardous condition there if the compartment is closed off.

Lift the tank out of the boat to fill it - gasoline entering the tank pushes the fumes out into the compartment where they will linger, being heavier than air.

Adding built-in tanks is more of a hassle than you might realize - you have to put in a filler neck where a spill won't run into the boat, and a vent leading outside the boat.

Here's a handy reference I used when configuring my fuel tanks - the USCG guidelines for boat builders:
http://www.uscg.mil/d1/units/actny/pandc/comdtpub16761_3bStd4BackydBoatBldrs.pdf

At 80% of WOT you ought to get more than double the run time than at WOT. This is just a WAG - expect maybe 2 or 2.5 hours at WOT from 6 gallons.

If you can make room, another 6-gal tank is a real handy thing to have.....

welcome to iboats!

 

[Silvertip]

Re: Gas Tank Problem/Question

At wide open throttle, a 60 HP engine will burn approximately 6 gallons of fuel per hour so you can run for one hour on a six gallon tank. Outboard fuel consumption is roughly 10% of rated HP. Some a tad higher, some a tad lower. Stated another way, that engine on a moderate sized planing hull would run about 30 - 35 MPH at WOT. In one hour you would therefore travel 30 - 35 miles. Using 6 gallons of fuel, that equates to roughly 5 miles per gallon which for a boat, is pretty good mileage and probably on the conservative side. I do have a ton of data to confirm those numbers by the way.

 

[snicklas]

Re: Gas Tank Problem/Question

Thanks for the responces, I was thinking about adding one of these tanks, are they supposed to be built in and do you vent to the outside of the boat
overtons.com/modperl/product/catalog.cgi?cname=Below-Deck-Gas-Tanks&r=browse&aID=21C"