safe and acceptable "fixes" for a marginally worn tank

leafybug

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So I've decided to pick all you experts brains to see if there is a way to repair my main tank on my 1988 25' Sailfish. Last fall I picked this boat up and thought it was in great shape. Needless to say the only thing that is in good shape is the polished hull. I knew I had to replace the deck panels that cover the fuel tanks (no big deal), when I pulled the covers I found the tanks covered in sludge. I decided to pull the tanks to clean them and the coffin boxs they reside in. Upon pulling and cleaning the tanks, I found their was a decent amount of galvanic corrosion and some pinholes in them. The bottoms of the tanks are worn a bit thinner than original. Is there any decent way to coat them and patch holes? I do have provisions to weld aluminum (yes I know I have to purge vapors). Is it safe to epoxy coat and maybe even add some fiberglass for structural integrity? The reason I ask is because of the 1200.00 cost to have a new tank built, and then the 4-500 extra for new filters, lines, tank beds, and other associated stuff. With a little effort I was thinking maybe, just maybe I can buy some more time until I need to replace them. Also, if anyone has ever replaced a fuel fill line on a sailfish I would like to talk with you regarding how. Thanks a lot guys in advance.
 

cgmiller

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When I pulled the main tank out of my 1990 Gulfstream, there was some isolated corrosion and I cleaned it and covered it with marinetez and then coated the tank with coal tar epoxy. My buddy pulled his tanks out of his 89 Gulfstream and he patched some pin holes with jb weld for aluminum. I replaced all of the hoses in my boat last summer and the fill hose to the main tank was a real treat. I had to cut an acces hole inboard of the fill pipes to get the screws out so I could pull the fill fittings. I also had to cut an access hole in the deck so I could fish the hose through the tight stringer holes ..there was no way to get the rigid hose through the holes. The vent hose I was able to trim to a point and pull with a string. Next spring I will try to tackle the fill hose to the auxilliary tank...after the main tank, I was done with that fun for 1 season and wanted to get the boat in the water and fishing....good luck!
 

Curmudgeon

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I found their was a decent amount of galvanic corrosion and some pinholes in them.

I've been there, done that, and paid a high price for the T-shirt when I bought my '86. The answer to your questions is, uuuuh, no. Do yourself a favor, bite the bullet and get new tanks rather than trying to put a band-aid on a bomb. What you're seeing is probably the result of some poor design, poor owner care (resulting in leaking hatch covers), and poor annual maintenance (Grady recommends flushing the tank tops at least annually) ...
:sorry
 

georgemjr

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I have replaced tanks on both an Overnighter as well as an Offshore. One was from the original manufacturer, the other from a local fabricator. Both were much less than your thought on cost. They were about 300 dollars each as I recall. You should be able to find a reference to this topic in the search. For the few hundred bucks, I thought doing it once and gaining 15 worry free years was worth it.
 

leafybug

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If you found anyone close to 300 bucks I would love to get in contact with them. The cheapest I have found is about 1200 for my 125 gallon tank. Florida Marine, which is where mine are originally from, wants like 1400 + shipping. My local guy at around 1200 also says to make is from 3/16 instead of floridas 1/8".
 

cgmiller

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Leafy,

You are not going to find someone to make tanks that big for 300 bucks today. I had a new 86 gallon tank made for my last boat (21 Mako) and it cost about 700 bucks. I coal tar epoxy coated it myself and saved about 100 bucks. I think the secret for an aluminum tank is to not let anything touch the surface of the aluminum. When I pulled my tank the isolated corrosion was where something was touching the metal.
 

Pez Vela

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Here are some pics of my '87 Sailfish fuel tank replacement. Money was no object ... to the fabricator. Having watched the entire fuel line extraction process, I can say that I'm glad I didn't try it by myself. Cutting tools are a must. viewtopic.php?t=8357&highlight=
 

gw204

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Scour Ebay, Craigslist, boating forums, etc for new leftover tanks. They are out there. About a year ago I scored a brand new, never had gas in it 81 gallon tank out of a Shamrock for $100. It even had the WEMA sender in it...
 

Grog

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If you have a little surface corrosion you might be able to get away with cleaning and cold tar epoxy. If you are at the stage where you might think there would be a hole, get a new tank. If it's that bad in the tank compartment, what's the shape of the stringers under the tank and the tank floors? If they're shot, $500 isn't going to cover it (not trying to rub in it).

Check the condition of the oil in the tanks, that was an expensive miss for me.
 

georgemjr

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500 covered the tanks I bought. One as recently as last winter. Do a search on this form. You will find original equipment fabricator as well as locals all in that price range.
 

richie rich

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$1200 for a 3/16 tank is about right.......the aux 75 gallon tank will be around $700......the original buiders in Florida are no bargain and you have shipping costs on top....where are you located?
 

Bryan3536

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Maybe a dumb question, but about to have a new tank fabricated - should I go ahead and preemptively epoxy? Seems some of you say yes, and makes complete sense to me.

By the way - I too priced out tanks from local fabricators, and prices I got were all in the $7-$8 per gallon range - $600-700 for the 79 gal in my Overnighter. I will double check these tomorrow, but pretty sure that was the rate.
 

leafybug

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Grog said:
If you have a little surface corrosion you might be able to get away with cleaning and cold tar epoxy. If you are at the stage where you might think there would be a hole, get a new tank. If it's that bad in the tank compartment, what's the shape of the stringers under the tank and the tank floors? If they're shot, $500 isn't going to cover it (not trying to rub in it).

Check the condition of the oil in the tanks, that was an expensive miss for me.

The tank "beds" and supports under them are pretty well shot, the bulkhead between the two coffin boxes is not great, and I belive I need to cut a hole in the starboard side stringer in order to chase my fuel fill hose. I picked up a sheet of 3/4" marine grade grade plywood yesterday (wow did the price of that sky rocket!) and plan to make the main tank bed, bulkhead, stringer hole patch, and a conversion from the rear tank bed to a new battery storage bank. I don't plan on re-installing the auxilary tank. I also need to reinforce the bulkhead on the rear of the main tank due to lack of aux. tank. I'm thinking just laminate and glass in a 2x4 of fir? That way it doubles as a floor support and tank support for the main? I think this is making sense...
 

leafybug

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Richie Rich, I'm located in mid-Michigan.

BTW, Yes I will syphon out the old oil and replace it with new yamalube. That is whats recomended for a pair of 88 yami 200's right?

Thanks for all the help guys, this projects is working on my nerves :bang :hmm :bang
 

richie rich

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Michigan is a good ways from Florida and New Jersey where the tanks were quoted, but I bet there are guys closer to make a new tank for you.....but metal isn't cheap anymore..so we gotta pay..

Not sure why you need to make a new hole in the stringer for the fuel line...should already be there..

If the bulkheads are shot, you may find more bad news when you cut it away and grind back some glass...so be prepared...hopefully, it stopped right there

You rear compartment for battery use may need ventilation for the battery gases...need a good design for that...

2x4 fir or a couple ripped pieces of the plywood epoxied together and glassed

as far as the tanks...yeah, clean them out to get rid of years of sediment..same with the oil line leading from them...You can stick with expensive Yamalube...I use Amsoil HP Injector which is a little less, smokes less and is full synthetic...but a lot of guys have switched to Pennzoil semi or full synthetic...a lot less money than both the others, smokes less, and they swear by the performance....this becomes a personal choice and at that age of the motor???
 

Grog

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If your layout is the same as mine ('91), you'll be going from the knees all the way up to the cabin with the tank floor supports. I used laminated 3/4 marine ply for the stringers, 3/4 marine ply for the knees, and 1/2" maine ply for the floors (gas and oil tanks). You should be able to use the existing hole in the stringer for the gas line but you may want to put an access hole by the fills. Not to rain on your parade but I have a feeling there's going to be more rot that you thought.

On the bright side it'll be better than new when you're done and if the wood is sealed it will never rot.
 

leafybug

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I was thinking to cut an access into the stringer in order to feed the fuel fill and vent lines up through the gunnel. I think it sounds drastic but I dont think that I'll be able to pull the new hoses with the old by attaching them together. I'm definately going to give that a shot before I go too crazy with the sawz-all. As far as my moisture issue goes, the stringers seem to be solid and fairly dry. It's the bulkhead that separates the two coffin boxes that wasn't sealed or glassed in on top, and the tank beds that were not sealed on the ends that are giving me fits.

I have a guy about 45 mins away that will build my tank out of 3/16" where stock was 1/8" and he's gonna run me about 1200. I think.

As far as your opinion on oil, Amsoil is the ticket? I've always heard that yamilube is almost necesary for these motors. I know that every manufacturer "recommends" their oil but its not always the best. I'm all for less smoke, better smell, and better lubrication.

Thanks again for all your help
 

leafybug

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while were on fuel systems, will a 60 gph raritan fuel filter be substantial for a pair of 200 yami's or do I need seperate filters for each engine?
 

richie rich

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"Fairly dry" is a relative term....epoxy or Vinyl ester resin won't stick to a damp substrate...need to be around 8%...if 10 or 12%, you are gambling but it may work...I don't think anything higher than 12% will be successful....if you cut away some of the grid, I would sister in some ply and add more glass to return the stiffness...seal the crap out of any exposed wood....the tank beds and bulkheads will almost always be wet on those older hulls...the factory never sealed them right....but you're on the right track with your replacement approach....

OIl? I'm an Amsoil user on anything and everything I own...I don't push it on anyone, its just my opinion and I have had nothing but success with it...have been running the HP in my 88 150's since 2004..and a previous 87 150 since 2001.....no issues....I personally like synthetic in general, but that's another can of worms when discussed on a forum...if you like Yamma lube and don't mind the cost, use what makes you happy...I have yet to hear of anyone losing an engine or being denied a warranty because they used another brands oil, as long as it's correctly rated for the application.....

As far as the fuel filters...you may be OK with what you have, but, I like using a seperate filter for each motor....this will give your fuel twice the filtering surface per tank of fuel and if you get one of the filters clogged for some reason, the other motor can still get you home....if a single filter clogs and you don't have a spare, you're SOL......I think most guys like having a Racor style 10 micron filter/seperator for each engine...one of these type..

http://www.defender.com/product.jsp?pat ... &id=133730