My first Gas Tank Leak- 1982 WellCraft Sportsman 248

[pzart]

I have to say, as many old boats I have had over the years, 4 that went on to other owners, 2 I now have, this is my first tank repair. She started smelling like fuel 2 weekends ago, so this last weekend I removed it. Thanks to WellCraft for making it easy on this one, just tip the captains deck up(10 screws and cut the 5200, scissor jack ) and slide the 100 gal tank out took me longer to hand pump the 38 gal of fuel out I need a better fuel pump.

Weld shop should have it ready before the end of the week, unknown cost at this time but sure it will be done right. Forgot to take pics but I will prior to install. Was really quite cool how they set it up for tank removal. My tank is 6 ft long, 22 wide, 16 tall.

What caused the leak was a rubber strap that the tank sat on, caused electrolysis on the outside where dirt,moisture,rubber and aluminum all sat together. where there was rubber and aluminum but no dirt and moisture....tank was perfect. We inspected the interior with a camera and it looks perfect, I am getting off easy with this one (knock on teak wood)  Like I said, will post a few pics later this week.

Thanks everyone, I would not have attempted this by myself without your repair posts, even though its a Wellcraft, it is the knowledge and confidence that all of you have that effects us all.

[wingtime]

Classic example of something against the tank causing a failure.  As you said rubber against the tanks traps moisture there and the carbon in the rubber causes electrolysis. Use silicone or vinyl pad under the strap.  Of 5200 a thin starboard strip onto the tank.  I mean really butter it up so nothing can get in between it and the tank.  Can't wait for the pics.

[pzart]

Pick up the gas tank from the welder tonight, $175 for the repair....

Here are a couple pics of the tank and one of the bad spots


Never noticed it before, but the ground wire was cut   definitely going to fix that  

[slvrlng]

So your welder actually fixed that?  

Is he going to pressure test it?

[pzart]

So your welder actually fixed that?  

Is he going to pressure test it?

Yep and yep,

spot is actually smaller than it looks in the pic

[pzart]

Well, it was a long Saturday but the gas tank is back in and no leaks I didn't take any photos of the removal but below are the photos of the re-installation....


This is to show the size of the tank, I am just under 6ft...


This is what the deck looks like from the rear, you step up into the helm area, the two windows are sleeping / storage :) area in the cabin. I jacked up the raised deck from under there.


Seam on starboard side where I cut the 5200 and removed screws....


Port side seam...


Pic of gas tank coffin with lid removed, this lid is not sealed down, has handle to access bilge area...


Pic of Helm area...


Port side sleeping berth where jack is setup, deck is up about 2"....


Starboard side berth, lifted 2"...


Port side seam lifted 2"...


Starboard seam lifted 2"...


Deck lifted 2"...


Port berth all the way up...


Starboard berth all the way up


Deck all the way up...


Lower deck and motor pic....


Dead tired....


So I took a nap....


Gas tank going in...


Tank half way in....


Tank sitting in it's coffin....


All strapped in and deck back down...

[Georgie]

Wow, man!  Nicely documented and well managed project!  

Were there no other significant corrosion spots on the tank?  How did your welder fix that one spot?  I couldn't tell from the photos, but it didn't look like he just covered it up with another piece of plate.  Any other flushing, de-gunking, protecting, polishing etc. steps you incorporated but didn't show?

[seabob4]

Well done Paul!  That doghouse overhead looks very similar to the way the Stamas 310 and 290 Expresses are built, whereas that overhead is a separate piece that forms the helm area as well, not part of the main deck, or cap, as some like to call it.  Good on WC to provide a hatch, as, by the time I got there, there were no tank hatches anymore, either WCs or AS's.  Want your tank out?  Major deck surgery...

[gran398]

Good job!

She's a fine ride...and this pic....

Defines true Aquanet devotion




Good on you bro

[pzart]

Wow, man!  Nicely documented and well managed project!  

Were there no other significant corrosion spots on the tank?  How did your welder fix that one spot?  I couldn't tell from the photos, but it didn't look like he just covered it up with another piece of plate.  Any other flushing, de-gunking, protecting, polishing etc. steps you incorporated but didn't show?

Thank you, There were 2 bad spots caused by the rubber end pads we discussed earlier in the thread, didn't think about taking pics of the welds, maybe next time. The "aluminum welder" (there are guys that "can" weld aluminum and then there are guys that weld aluminum all day long at work, most of these guys that weld aluminum at work are known to have there own home shop too.) cut out the bad spots and welded in new pieces. He told me I didn't even need to pressure test it cause he did a great job so after I had it pressure checked....I found out he was right.....no leaks :)

He suggested spraying the bottom with undercoating because of the welding, grinding and new aluminum plates, something about losing it's protective coating. Good or bad idea? don't know...we'll find out in another 30 years :)

Used that starboard stuff, adhered to the tank, for setting the tank up off the fiberglass bottom, but used the same top mounts with a rubber strap under them, just like it was originally done. Looks like WC used some sort of poplar wood for those top mounts.

Inside of tank was pristine, tank had rotted from the outside. No other work was done.

I had suspected a leak for sometime, but it was minor, only smelled when cover was on for a couple days, never smelled any fumes from the bilge vents until that last week before I pulled the tank, when it got worse. My boat cover covers the bilge vents so at first I thought I was just getting bilge fumes under the cover. Hind sight.......If you pull your cover off and you smell anything but that old salty boat musty smell, you have some sort of leak

[slvrlng]

Excellent job!!! The pic of you in the coffin is hilarious! There is a school of thought that believes the carbon in undercoating, can and will attack the aluminum and cause corrosion. As you said time will tell. gran used this stuff at my suggestion. It is a wax type product that self seals and creeps into seams.

http://dominionsureseal.com/index.php/c ... corrosion-

[pzart]

Excellent job!!! The pic of you in the coffin is hilarious! There is a school of thought that believes the carbon in undercoating, can and will attack the aluminum and cause corrosion. As you said time will tell. gran used this stuff at my suggestion. It is a wax type product that self seals and creeps into seams.

http://dominionsureseal.com/index.php/c ... corrosion-

thanks, I'll get some of that stuff, have a bunch of uses for it. I looked in all the automotive stores for undercoating that said it would not harm aluminum, the only one I found was at advanced auto, some super duper professional formula.....

[Capt. Bob]

There is a school of thought that believes the carbon in undercoating, can and will attack the aluminum and cause corrosion.

I'd be more worried about anything that can trap moisture against the aluminum surface. I'm not so sure that "carbon" gives or takes electrons so easily as to cause aluminum to corroded all by itself. A lot of "thought" but little proof. You can have aluminum straps against the aluminum tank but if water gets trapped between the two, they will corrode.

If you want to use a carbon based product (I used neoprene) for a little cushioning effect, just place something between it and the tank (5200 comes to mind) and remove all doubt. 5200 apparently doesn't cause corrosion and quality builders use it between ss fasteners and aluminum to prevent corrosion between those two dissimilar metals.

Here's another take on tank protection.
viewtopic.php?p=16884#p16884

Good luck

[seabob4]

From what I've read, that same electrolytic carbon concept is behind the reasons we didn't store batteries on concrete (old batt cases were heavy in carbon content).  Although I STILL don't put them on concrete...

But today's plastic cases are...plastics, made from oil, which means they are carbon based...  

[Capt. Bob]

From what I've read, that same electrolytic carbon concept is behind the reasons we didn't store batteries on concrete (old batt cases were heavy in carbon content).

Rubber cased batteries could lose a charge (if left long enough) on the "ground" be it concrete or mother earth due to the fact that the cases in those days were more porous and the electrolyte might seep through the case causing the stored current to pass to ground. The carbon content may have helped with current flow in those cases but I'm not so sure. Carbon is used in resisters to help control flow of electrons. I'm not scientific enough to know more. It's not completely logical to me.

 My dad harped on this all the time. "Put a board down you idiot".

Temperature also effects the battery's ability to hold a full charge. Concrete is a rather poor insulator so the internals get colder on those "cold, damp floors".

Although I STILL don't put them on concrete...

I'm still an idiot and yes I still put a board down too. They still provide a bit of insulation here in chilly Fla.

But today's plastic cases are...plastics, made from oil, which means they are carbon based...  

Greater density in material + less chance of seepage = low power drain when stored.

Like the anti corrosion fluid Lew mentioned. 40%+ mineral spirits. Carbon based.