Gas tank question

[flatshead]

I went to a couple yard sales and I bought an aluminum gas tank 10 or 12 gallon. I have a plastic one now. Which would be better to use? I only paid 5 dollars for it.

 

[sasto]

Re: Gas tank question

Most builders are going poly tank. Alum, If not installed correctly, can give you problems in the future.

 

[NHGuy]

Re: Gas tank question

Start out by leak testing with air pressure. If it's good remove any old gas and clean it out well, then keep it covered once it's clean, dirt in fuel = trouble. Look for a proper mount spot. Remember the tank & fuel will weigh 100 lbs or so. So don't mount it on the heavy side of the boat. It should probably go on the opposite side of the driver position.
What kind of engine do you have? What kind of boat do you have? Trihull? Vee hull? Fishing? Bowrider? Closed bow? Where you put the tank is dependent on that stuff, plus weight distribution and available space.
You will need plumbing to get the fuel to the engine, a gauge & sender, a vent & vent hose and you will need a filler & neck. I am guessing you have an outboard. If so you will need a section of flexible fuel hose with a pump bulb to go between the hard plumbed line and the engine. The filler is mounted externally so any spilled fuel won't go in the bilge.
Sounds like a pain but it might be worth the work, I grew up on a boat with "carry" tanks, then I got one with built in and carry tanks. Now the one I have is straight built in. I like the built in best. It's in position, out of sight and does not take up room from my other stuff.
Grounding is critically important, look up the standards and follow them or you risk a fuel explosion. Basically you ground the tank and the filler fitting. The filler tube and fuel line are marine specific and the filler tube requires double stainless clamps on both ends.
You will need some way to secure the tank to the boat too, maybe a glassed in level spot with hold downs so the tank can't move around.

I think you may have to spend some money to do the install. Might out strip the $5 you spent on the tank!

 

[seabob4]

Re: Gas tank question

First, the pressure test is the important thing, 3 PSI for 14 mins. That will tell you if you have a leak. Second, yes, the fittings and plumbing WILL cost you more than $5.

I have to disagree a bit with Sasto. At Proline, as well as when I was with Wellcraft, we used poly tanks up to a certain size boat, aluminum on the larger boats. There is a big cost difference between the 2...

 

[sasto]

Re: Gas tank question

I have to disagree a bit with Sasto. At Proline, as well as when I was with Wellcraft, we used poly tanks up to a certain size boat, aluminum on the larger boats. There is a big cost difference between the 2...

I don't get the disagreement. I agree with you. But he is looking at a very small tank. Your Proline's are a great boat with a polly tank. Isn't it?

 

[109jb]

Re: Gas tank question

First, the pressure test is the important thing, 3 PSI for 14 mins. That will tell you if you have a leak. Second, yes, the fittings and plumbing WILL cost you more than $5.

I have to disagree a bit with Sasto. At Proline, as well as when I was with Wellcraft, we used poly tanks up to a certain size boat, aluminum on the larger boats. There is a big cost difference between the 2...

3 psi on a rectangular tank is way too much in my opinion. if one side of the tank is say 1.5 feet by 1.5 feet you have the equivalent of almost 1000 pounds of force on that side. Even if the tank holds you will likely permanently deform the tank. It can also explode violently. 1/2 to 1 psi is more than enough to check for leaks. I actually just attach a balloon to one port, plug all the others except one to add air and then just add enough air to inflate the balloon. come back the next day and if the balloon is still inflated you are good.

As far as the original post, if your plastic tank is still good then I wouldn't change it.

 

[flatshead]

Re: Gas tank question

Thank you all for the replies, they were all very informative. I think I will just keep the poly and sell the aluminum one in my next garage sale.

 

[seabob4]

Re: Gas tank question

3 psi on a rectangular tank is way too much in my opinion. if one side of the tank is say 1.5 feet by 1.5 feet you have the equivalent of almost 1000 pounds of force on that side. Even if the tank holds you will likely permanently deform the tank. It can also explode violently. 1/2 to 1 psi is more than enough to check for leaks. I actually just attach a balloon to one port, plug all the others except one to add air and then just add enough air to inflate the balloon. come back the next day and if the balloon is still inflated you are good.

As far as the original post, if your plastic tank is still good then I wouldn't change it.

3 PSI, 14 Minutes. ABYC Standards. This is up to a certain capacity. If the capacity is greater, the time is greater.

I work in the business, I've been pressure testing tanks for 16 years...

Sasto,
Nothing wrong at all with poly tanks. Frankly, I think more owners should go with them. At Wellcraft/Aquasport, when I was building mainly AS's, the 225 Osprey had a 102 gallon poly tank made by Inca Plastics, same company we use at Proline. Yet the 245/250 Osprey got a 141 gallon aluminum tank made by RDS...what's the difference?

 

[sasto]

Re: Gas tank question

3 PSI, 14 Minutes. ABYC Standards. This is up to a certain capacity. If the capacity is greater, the time is greater.

I work in the business, I've been pressure testing tanks for 16 years...


How true that is. ALWAYS stamped on alum tanks we ever purchased. Made sure of that!

 

[sasto]

Re: Gas tank question

Sasto,
Nothing wrong at all with poly tanks. Frankly, I think more owners should go with them. At Wellcraft/Aquasport, when I was building mainly AS's, the 225 Osprey had a 102 gallon poly tank made by Inca Plastics, same company we use at Proline. Yet the 245/250 Osprey got a 141 gallon aluminum tank made by RDS...what's the difference?

The difference is exactly as you stated. He is looking at a 10 gal tank....... Why poly vs. alum? I would assume because of baffles easily inserted in a large alum tank would add sidewall strength, in turn add stability to the vessel and tank. Dunno, seabob, I'm here to learn. We have fiberglass tanks that hold 950 gals. I really don't want either for this application. I am a fan of plastics when applicable.

 

[seabob4]

Re: Gas tank question

Sasto,
Baffles are in both types of tanks. The baffles in a poly tank are molded on one half, that half is pulled, the cap is ultrasonically welded to the other half. All Inca and Moeller tanks are fully baffled. It basically becomes a matter of cost. As the size of the tankage grows, so does the size of the molds that the tanks are formed from. Mold making costs BIG money. If you, as a builder, want to have a really large tank, say a 1000 Gallons, made out of roto-molded polyethylene, you can have one...but you have to pay for the mold too, and if your production is high enough, you can amortize that tooling cost across the amount of boats you build with that tank..but if not, it becomes prohibitively expensive...hence, you go with aluminum.

 

[flatshead]

Re: Gas tank question

Again thank you all !!!!