Rusted out fuel tanks

[Bigfish]

Still haven't gotten a look at how bad my two 350 gallon tanks are but the major fuel spill last week is a pretty good indication its going to be a major fix... Lots have suggested different ways of solving the problem, none of which are particularly attractive... How about THIS! I cut open my deck above the tank, cut off the top of the tank, and insert a new poly tank slightly smaller into the old tank. Plumb it up, redo the deck and I'm done...

 

[Comodave]

If the old tank has much capacity it will have baffles dividing it. It will have to be a really small poly tank to fit in between the baffles.

 

[Larry M]

Before you cutting the deck(s) apart, get a way to look at the top of the tanks. Look at how the deck beams run. Can you “sister” in new deck beams and finish the decks so they look as they were when built? I’ve seen hack jobs on boat repairs that basically make the value of the boat = 0.

Find the source and how the tanks are installed before you get the sawzall out would be my suggestion.

 

[RT Firefly]

Greetings,
Mr. B. You could also cut a big hole in the side of the hull and gain access that way. Several ways of approaching the problem. Some sane, others, not so much. If the situation is stable at the moment, you have time to do some more research. I'm sure there is a simple, yet elegant plan that you may not have though of yet...Patience grasshopper...

 

[Bigfish]

I intend to do that...

 

[Bigfish]

Not in any rush...

 

[Bigfish]

Can't the baffles be cut out??

 

[SoWhat]

Can't the baffles be cut out??

Yes, along with the whole tank. Baffles are welded so it would be difficult to grind the seams flat. The tank walls are thin so you might end up with many abrasive spots. Anything can be removed with right tools and sufficient time.
Put a borescope in the fill tube and you will get a better idea of baffle construction.

Instead of removing structural deck, why not remove panels covering fuel tanks in the ER?

 

[rslifkin]

Can't the baffles be cut out??

Yes, but by the time you cut them out, smooth out any rough spots that might rub on a new tank, etc. you might as well just cut the whole tank out and mount the new one without the old.

 

[Bigfish]

Because I'd have to remove the engine to access it that way

 

[Lepke]

Since you're looking for a cheap, easier way to solve your tank problem... If the side or end can be accessed, you cut a hole clean the insides to remove diesel, and use a thick tank coating made for diesel. Maybe 2 coats. Then the tank should last the life of the boat. The hole you cut gets a gasket and the piece removed gets ss flat bar all around the edge to make a lip. Drill some holes in the lip and tank, bolt, and you're in business. There are ready made access ports that weld in.

Another cheap way is drain the tank, buy a sawsall and cut it in pieces to remove. Then make one out of plywood and fiberglass. Build/fiberglass in place. Not the best, but does work. Won't look good in a survey. Lots of home builders have made good fiberglass fuel tanks. Probably what I'm going to do if my 1942 steel tanks fail.

 

[koliver]

Because I'd have to remove the engine to access it that way

Seriously look at the real cost of lifting the engine(s) out of the way. You can dismantle to ready them for removal, get a guy with a forklift or a truck mounted crane to do the heavy lifting, re/re your tanks and reverse the process.
That all will likely be less costly than repairing cut decks or hulls after creating a new opening.

 

[SoWhat]

Because I'd have to remove the engine to access it that way

I think removing the engine is far simpler than you think. Uncouple the transmission, remove the 4 mounting bolts, and away it goes. Build a frame on the main deck to attach the chain lift.

Removing structural decks and rebuilding them sounds like a serious project.

 

[bogranjac1]

Sell the boat, fixed the problem

 

[mvweebles]

Seriously look at the real cost of lifting the engine(s) out of the way. You can dismantle to ready them for removal, get a guy with a forklift or a truck mounted crane to do the heavy lifting, re/re your tanks and reverse the process.
That all will likely be less costly than repairing cut decks or hulls after creating a new opening.

Agreed. Assuming adequate access to remove the engine, decent diesel mechanic can have an engine out in about a day. Getting it back in and aligned might be a couple days.

 

[mvweebles]

Sell the boat, fixed the problem

Suppose the boat had a value of $75k before the fuel tank failure. What do you suppose the value is now, especially since the boat is likely uninsurable (no loan, no marina). Any suggestions on actually finding a buyer at any price? I can't imagine a broker would bother, so would have to be a private sale via Craigslist or Ebay.

My sense is the tank issue must be addressed. And relatively properly or the boat will continue to be an albatross.

 

[rslifkin]

Keep in mind, if there's enough room to work, an engine doesn't even need to come all the way out of the boat. It just needs to be lifted out of the hole and moved out of the way. I think Comodave did that to get to one of his tanks.

It wouldn't be too hard to build a framework to lift from to allow pulling it cheaply.

 

[timb]

i cut a hole to look in mine and it started stinking up the boat so over two days i cut it out with a cheep saws-all from Walmart(most of the time was waiting on batteries to charge). the best way i found to empty the tank was to remove the top of the sight gauge and pull it out with an oil change pump. when its empty. poor a cup of water at a time in the fill and pull more out with the pump .repeat this until you get water out . i only cut down a wall (piece of plywood) and removed one bolt in support.

 

[mike50]

Since you're looking for a cheap, easier way to solve your tank problem... If the side or end can be accessed, you cut a hole clean the insides to remove diesel, and use a thick tank coating made for diesel. Maybe 2 coats. Then the tank should last the life of the boat. The hole you cut gets a gasket and the piece removed gets ss flat bar all around the edge to make a lip. Drill some holes in the lip and tank, bolt, and you're in business. There are ready made access ports that weld in.

Another cheap way is drain the tank, buy a sawsall and cut it in pieces to remove. Then make one out of plywood and fiberglass. Build/fiberglass in place. Not the best, but does work. Won't look good in a survey. Lots of home builders have made good fiberglass fuel tanks. Probably what I'm going to do if my 1942 steel tanks fail.

Use 2 part polysulfide, aircraft tanks are sealed with it all the time. Smith and Co may still sell it, if not aircraft supply company’s carry the product.

 

[Larry M]

Use 2 part polysulfide, aircraft tanks are sealed with it all the time. Smith and Co may still sell it, if not aircraft supply company’s carry the product.

Flamemaster CS 3204 is recognized as a great tank sealer. I’ve used it on Hobo and can vouch for it.

https://www.skygeek.com/flamemaster...lTT1b44WU8lky4k168fsQZl_i_pLEx00aAhGzEALw_wcB

 

[C lectric]

I think you need to get a look at the tank FIRST to actually assess the extent of the problem. Untill that is done you cannot know what needs to be done.
The tank may be salvageable but untill you get a good look at it all the rest is just panic.

Figure out where you can cut through the paneling so you can see into the enclosure. Once done DO NOT replace the enclosure.

Then and only then will it be possible to come up with a decent plan.

A friend of mine had a similar problem, tri Cabin boat similar to yours , single engine, twin tanks cradling the engine. One tank leaked. THe engine was simply shifted to the side out of the way and blocked. The leaker was then cut out and replaced, then the other side was done.

He did not do it himself as he had no mechanical skills at all but the point is it was doable without butchering decks.

 

[twistedtree]

Is it even certain that it's the tank that's leaking, as opposed to the fill hose or associated parts? The leak occurred while filling, so it seems it could be either. And you approach to repair would be quite different.

 

[fryedaze]

Lots of threads on Fuel Tank Replacement.
http://www.trawlerforum.com/forums/showthread.php?t=39628

 

[JohnP]

Is it even certain that it's the tank that's leaking, as opposed to the fill hose or associated parts? The leak occurred while filling, so it seems it could be either. And you approach to repair would be quite different. Well I would approach this problem from the engine compartment. I find it a little hard to believe if all the salon floor hatches were removed and one were to lean over or even lay on top of the engine you could not begin working on the issue. Number one I would remove the tile and or plywood wall hiding the tank even if I had to cut it out in little pieces. Wet the tile down with water try and pry them off with minimal breakage, put them in a heavy duty garbage bag. Wear a good mask they probably contain asbestos! After they are gone hose down the area with water and pump out. If the wall is plywood you can probably cut it out. Now you can check out the tank top and filler hose. Best case the filler hose has rotted or cracked or the clamps rusted off. Easy fix!
If the tank top and filler neck are rusted away you have to decide if you are comfortable fixing it or if is time to cut out the whole tank.

On a 42' boat I would thing the engine compartment would be long enough and if enough stuff were removed you could put a new smaller tank in and move it into position along side the engine. Batteries, and water heaters and even generators are not as hard to move as engines. Moeller makes lots of different sizes and shapes of poly tanks. I put a pair of them in my last boat. I lost alot of fuel capacity but if you use your boat as we did mainly on the ICW fuel was never a problem

Good luck--I would not cut the deck unless you also are planning a complete teak deck removal in the near future.

 

[JohnP]

Picture of polytank in my old boat.

 

[oscar]

Just get someone in there who knows their stuff to assess and give you options already.

All this speculation is just that. This is not rocket surgery, but you have to be looking at it.

Sheesh.

 

[FF]

There is one caution to installing a polly tank. .


Place it , fill it with diesel and give it a few days to expand, Then secure it in place.

 

[Sea Fever WNK]

Rusted Fuel Tanks

I cut both rusted 300 gallon tanks out of GB 42.Slid engine forward on Starboard side and removed Gen-set for port side. Drain tanks first.
sabre saw with tapping grease was the trick, no steel sprayed around engine room, and blades lasted longer.
I had 3 tanks made for each side just wide enough to het thru Main Salon Doors. Tabs were welded to each tank so I could bolt the together to form
one large structure. The aft tank 82 gallons is my Day Tank the middle and forward tanks ,same capacity, are storage tanks. I have a manifold that allows me to pump 3+ gallons per minute into any of my tanks. so I polish my fuel a lot. I pull and return to the day tanks so my fuel in the day tanks remain clean. We can cruise at approx. 1700 RPM (135 hp Ford Lehmans) for 13 hours and only use 40 gallons out of 82 capacity.
This has worked really well for me. I did not cut up the boat, I cut up the tanks. New tanks are 6061 Alum, powder-coated with shiny white epoxy.
they look great, built all ne cribbing using same profile as original tanks.
pot PVC protection at corners and botton held on by 5200, and closed cell Neoprene foam.
This all sounds like a big job, but everyone who looks at it says holy smokes you did it right. That is the point do it once "right". trust me I put a lot of though into this, and time. BUT all my time was spent installing a first class fuel system with KeenanFuel polisher. I spent "ZERO" doing fiberglass repairs etc. required when you cut up the boat. Cutting tanks out was 2 people 2 weekends. Re-stall was longer as great care was given to cribbing. Aft Day Tank went in first so all cribbing was done off of that.
Tanks Have 6" inspection ports.
Clean Fuel is the best thing to feed your diesel, period.! We have increased the value of our 1985 G/B-42. The reason is that we didn't do anything until we could do it right, and we took time to research what was right for boats much larger than ours and copied their systems. We Date everything with a Dimo Label maker, and we keep a Sales brochure that we up-date each year, as someone else will own our boat when we are done with it.
The sales brochure is more motivating to keep up with, and it also gives us the opportunity to look back at what we did 10 years ago, when we started and check to make sure all components are still working well.
Have Fun !!!