INSTALLING FUEL TANK

[osprey170]

It's been a while since I posted here, been working like a mule for the past year.  My boat has been laid up without a fuel tank, old one was corroded and leaking.  I'm finally ready to replace it - I'm going to get my tank from Alloy Metal Works out of New York.  Couple of questions, and hopefully JDupree will chime in on this.  When I order my tank do I ask them to tap the holes for the vent and fuel pickup?  I wouldn't know what thread pitch or how to measure pitch.  I got the brass fittings from my old tank off.  I guess I could do it myself but I was concerned about getting metal in the tank, or should I not worry about that?  Also needed info about coating and mounting the tank.  I have heard some folks coating the tank with coal tar epoxy.  Anyone have an opinion on this?  Good, bad?  I read the article floating around here about using plastic strips and 5200 to glue down the tank, but it seems to me like this would come unglued after a while and cause the tank to bounce around the tub.  I just want to make sure I do this right because I do not want to ever have to take the deck back up.

Thanks guys and hopefully I'll be back on the water soon!

[John Jones]

I would think the tank would come with the necessary connections welded on.

For installation see How to Install an Aluminum Fuel Tank. . . .  
So you Don't Have to Do It Again by David Pascoe

http://www.yachtsurvey.com/fueltank.htm

Don't forget the USCG requires all components including the filler to be grounded.

[warthog5]

Pascoe's article comes up all the time.

Nothing wrong with it except for one thing.

His system is designed for a BIG boat. No big boats here.
He talk's about air flow in the bilge area. There is no air flowing around in these smaller boats we have. So his method really doesn't apply.

Here was my latest install in a 20 Mako. Scroll down.

http://www.classicmako.com/forum/topic. ... hichpage=1

[John Jones]

My '79 AQ 22-2 has air flow right over the tank.  Scoops mounted on either side of the console and something like plastic dryer vent hose from the scoops going below the deck.  One scoop faces forward for forced air and the other to the rear to help evacuate.

Port side scoop faces forward


Stbd side faces aft


Hose under console

[cervo]

When I got my tank from Alloy Metal Works, the tank was complete with fittings in place.  If you aren't going to change the tank set-up, I would send him a picture of what you have with the measurements.  He also made replacement securing staps.  I don't know what your set-up is like, but in my 73 22-2 the straps are skrewed into the stringers, bent over the tank and drawn together with a nut and bolt. With the new straps and the method of using plastic strips with 5200, I'd say that it's a remote chance of the tank breaking loose.  You also might want to ask him for the strips of rubber to put between the straps and the tank.

[JimCt]

Ditto's what cervo said.  Alloy will supply the tank all set to hook up.

[warthog5]

You also might want to ask him for the strips of rubber to put between the straps and the tank.

Having pulled a few tank's.  I have seen the results of rubber in direct contact with alum.

The tank's were fine except where that contact point was made. It was corroded badly there.

This is because rubber & neoprene have carbon in them. The carbon attacks the alum.

[osprey170]

Thanks for all the feedback guys!

I've read the yachtsurvey article and that's where I got the idea of glueing the tank down with 5200 on plastic strips.  It just seems like after a lot of pounding the tank would eventually work loose.

I too have read that rubber and aluminum in contact is a big no no because of the carbon issue that warthog brought up.  The tank in my 170 was foamed in.  I never found out where it was leaking but it was really corroded where the foam contacted the tank on the underside.  Some of the foam was still wet.  I've thought about coating the tank in coal tar epoxy and foaming it back in.  I figure it lasted over 20 years without a coating in a foam installation.  If I got 15 out of this next install I would be happy.

I didn't even think about having Alloy put the fittings on - I'm sure he's done plenty of tanks and knows what he's doing.  I'm going to call him on Monday and tell him what I got and ask him what he can do.

Thanks again guys!

[JimCt]

When I pulled the two bad tanks out of my 240 I was an idiot and tossed 'em.  Had I kept them the tank fabricator for my new tanks would have been able to duplicate the fitting locations.  Luckily I have pictures & basic dimensions and the fitting locations are not that critical, but still I should have hung on to them.  Some days I get on a house-cleaning binge & throw out everything in my way and regret it later.

[jdupree]

I measured where all the fittings were on the original tank of the 170.  As a matter of fact, I still have the diagram drawn with all the dimensions of my tank.  My 170 was a 1988 model which had the 27 gallon tank in there.  I would assume the tanks are the same size.  Give me your e-mail address and I will send it to you.

As far as mounting, this is what I did.  I just simply dropped the new tank right in the tub and strapped it back in.  The only thing that I did is where the straps contact the tank I made rubber strips to keep the tank protected from the strapps rubbing.  That is it and my tank did great.  Hope this helps.

[osprey170]

eddie@advtex.com

JD did your boat originally have the tank strapped in or did you buy a mounting kit?

Thanks!

[jdupree]

eddie@advtex.com

JD did your boat originally have the tank strapped in or did you buy a mounting kit?

Thanks!

The tank was held in place by the original metal straps.  If you will look at my CCP thread you will see the straps and they look like they did in the 170.  Do you have the straps   If you do, just strap it back in and put rubber where the straps contact the tank.  Seal your hatch good and you won't have a problem.  I will e-mail you the diagram of the original tank in my 170.

[osprey170]

Thanks for the drawing JD.  My 170 has the same size tank but has the fittings in different places.  The vent and fill or on the front of the tank and the pickup is in the rear with the seding unit cutout dead center of the tank.  Also, the tank on mine was foamed in, no straps.