Replacing fuel tanks

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C

Curt R

Member
Joined
Nov 27, 2012
Messages
12
Location
USA
Vessel Name
April Dream
Vessel Make
1982 MMC Trawler
I was advised that the starboard fuel tank is leaking and needs to be replaced (Not news I needed to hear) the Mechanic transferred fuel to the port tank avoiding more serious problems. My boat is a 36' Monk Trawler. 120 single Lehman. Does anyone have experience changing these tanks? Boat is berthed in Sausalito Ca. Any recommendations for mechanics who do this type of work in the Bay Area? Should I haul the boat for this work or leave at the berth? Any and all ideas/suggestions are welcome.
 
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My suggestion, search this forum for one of the many threads on this and all your questions will be answered. Many times, with many different answers. :D
 
Did you ask the mechanic who drained the tank if he did this? Or does he know anyone local?

This is usually not as simple as 'rip it out and throw in a new one'. Especially if you were thinking of DIY. You have to assess whether the tank can be cut up in situ, or will have to have beams, engine or other tanks removed also. Someone will have to come look at your vessel. Ask at several yacht yards for recommendations.
 
One recommendation you will find discussed if you do a thorough archive search as Capt. Bill suggests is if the only way to remove the tank(s) is to move or remove the engine, have the original tank(s) cut up in place so the pieces can be removed without having to do anything with the engine. Then have several new smaller tanks designed and fabricated that which be installed without having to do anything with the engine to get them in.

Depending on the amount of space and clearance in the engine room and the design of the tanks you may or may not lose some fuel capacity by doing this but if you do it probably won't be much.

For example the twin-engine cabin cruiser we have in the PNW was built in 1973 with three 150 gallon fuel tanks: one on each side of the aft end of the engine room and one across the back of the engine room. I assume one or more of these tanks developed problems because the year before we bought the boat (1998) the previous owner had all three tanks removed, the generator repositioned, and five new tanks fabricated and installed.

Four of the new tanks are 85 gallon "cubes" with a pair on each side of the engine room where the original saddle tanks used to sit. The fifth tank is a 60 gallon day tank which is mounted in the bilge on the center-line of the boat under a new set of floor plates.

This arrangement reduced the boat's fuel capacity by 50 gallons which is good, actually. We still have more than enough range but we go through the fuel a little faster which means it doesn't sit on the boat as long. And having five tanks gives us some nice options for fuel management.

I suspect the original tanks were cut up in place and the pieces removed. The new tanks are all small enough to have been lowered into and positioned in the engine room without having to remove the engines. However judging just by eye I suspect the transmissions had to come out to provide sufficient clearance to get the saddle tanks into their mounting frames.

Finally, if one tank in your boat has gone bad and these are the original tanks it's very possible the other tank may not be far behind. Given the effort and expense of removing and replacing one of the tanks, and if you plan to keep the boat for a fair amount of time, it might be smart in the long run to replace both tanks.
 
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You might want to ask on the Monk 36 Owners Assoc site on yahoo. I know there are discussions there on the topic.
 
Marin said:
Finally, if one tank in your boat has gone bad and these are the original tanks it's very possible the other tank may not be far behind. Given the effort and expense of removing and replacing one of the tanks, and if you plan to keep the boat for a fair amount of time, it might be smart in the long run to replace both tanks.
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If you don't plan to keep the boat for any length of time and if you don't replace the port tank, any potential buyers will beat the cost of replacing it out of you.

Either way you are going to pay for both tanks.

Here is a start:
http://www.trawlerforum.com/forums/s3/tank-material-13452.html
 
I had a fuel leak in the corner seam of a large diesel tank on a Albin Tri-Cabin. The leak was toward the top of the tank. I had the boat in a charter program on The Chesapeake at the time and the charter company watching over the boat broke the news to me over the phone.

We were considering cutting the side of the boat out to replace the tank. We were considering removing the engine to get to it. We were talking about it being out of charter (and my use) for months.

I got a call the next day from the charter manager who told me that his welder had meandered into the office and overheard them talking about the problem. He went down to look at it and stated that he would weld the seam for $200. The charter manager asked me what I thought?

I was in Cincinnati at the time, so I said: "Go ahead."

Turned out that the weld worked. Never leaked again. I was also surprised to find out afterward that the welder didn't even empty the tank. He drained it so the fuel level was about a foot lower than the weld.

Best $200 I ever spent on the boat!
 
This has got to be the most ridiculous post I've ever read, "give it a shot", more like roll the dice on an explosion! Don't ever repeat this story again PLEASE!
Cuttyhunk47 said:
I had a fuel leak in the corner seam of a large diesel tank on a Albin Tri-Cabin. The leak was toward the top of the tank. I had the boat in a charter program on The Chesapeake at the time and the charter company watching over the boat broke the news to me over the phone.

We were considering cutting the side of the boat out to replace the tank. We were considering removing the engine to get to it. We were talking about it being out of charter (and my use) for months.

I got a call the next day from the charter manager who told me that his welder had meandered into the office and overheard them talking about the problem. He went down to look at it and stated that he would weld the seam for $200. The charter manager asked me what I thought?

I was in Cincinnati at the time, so I said: "Go ahead."

Turned out that the weld worked. Never leaked again. I was also surprised to find out afterward that the welder didn't even empty the tank. He drained it so the fuel level was about a foot lower than the weld.

Best $200 I ever spent on the boat!
Click to expand...
 
Greetings,
VERY lucky, but VERY stupid welder! I concur with Mr. Mm. Not only ridiculous but insane! I'm quite sure some tanks can be welded in situ but not without a strict protocol to minimize risk. NOTE: I said minimize NOT eliminate.
 
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Atl makes a blatter tank that fits inside the old tank don't know of anyone who has done this before but it should work you will have to cut the tank and remove any baffles
 
Marlinmike said:
This has got to be the most ridiculous post I've ever read, "give it a shot", more like roll the dice on an explosion! Don't ever repeat this story again PLEASE!
Click to expand...

The story was told in a flippant way because I couldn't believe that it could be done, but the welder knew what he was doing. The yard was convinced that there was no danger and the procedure did work. This was not a yarn. It happened.
 
Nitrogen, argon, co2, makes no difference its just used to replace the oxygen. No oxygen NO EXPLOSION. Personally I prefer fuel in the tank to below the spot to be welded, less air space. I generally use a MIG welder but have used stick on steel (black iron ;) tanks. I would suggest doing a little research and maybe learn a little about welding and what is considered normal practices befor saying something is "stupid" that any proffesionall welder considers everyday stuff.
 
Before making remarks using the word [stupid ] --better to keep one's mouth shut than open it and remove all doubt-- The weld was completely routine. What would be [stupid] is spending thousands to cut apart the old tanks , fabricate new ones, move engines and transmissions, for a repair that a 200 weld obviously fixed.
 
steveandtina said:
Before making remarks using the word [stupid ] --better to keep one's mouth shut than open it and remove all doubt-- The weld was completely routine. What would be [stupid] is spending thousands to cut apart the old tanks , fabricate new ones, move engines and transmissions, for a repair that a 200 weld obviously fixed.
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That same concept can be applied to so many thing here on TF that people have never seen or understand.
 
Hmm. I vote for JB Weld.
 
well rt, if you look a bit on the net you can find anything and all kinds of uninformed people to substantiate any position you may take. As a former proffesionall welder I can say with certainty that the welding apprentices (put nicely) in your first example dont have a clew. The second example seems to be a company trying to prevent accidents caused by employees similar to your first bunch. I can understand that, and yes, welding a fuel tank is serious business. As is heart surgery, but its done successfully everyday. Granted its by proffessionalls that know what they're doing. In both cases. If done correctly people dont usually die.
 
I've given up commenting about welding on this forum several years ago. I'm convinced everyone on this board knows better than I what I can and cannot weld.

Btw. I prefer to weld fuel tanks as full as possible too. As stated earlier in this thread, no oxygen no boom boom. But then again, what could I know?
 
Gentlemen (Kulas& Steve&Tina), thank you for chiming in with your experience on this. I felt like I was kind of hanging out there without much more then being able to say it happened and that the weld held for as long as I owned the boat.

And RT & Marlin, I don't blame you for doubting this. When the yard called me and told me that it could be done safely, I told them "If you say so, I'm just glad I am a 1000 miles away." Believe me, with the millions of dollars investment in their Big Time marina and repair facility in the middle of a population center in Maryland, they were not going to let some half drunk homer light a torch to "see if it works".

Before the welder did his magic, we had determined that the cheapest and easiest way to change that tank was to take it out of the side. This was a yard that stated they could cut the hull, repair it to stronger specs than new, and have the job done in 1/3 the time of removing the engine, cutting the old tank and producing and installing a new tank.

Like I have said before, when you have a repair present itself on one of the older Taiwanese boats, you start digging for the big boat units to pay for it. This was one of the more pleasant surprises I ever had in boating.
 
I agree with CP. I think someone once said "not having any idea what you're talking about in no way inhibits the ability to speak".
 
sorry ,firefly, your anecdotes carry all the weight of a helium balloon in this discussion--having said that-- I think the picture on your profile is really cool!!
 
If it is necessary to weld a fuel tank a full tank is the better way to go with some dry ice dumped into it prior to welding. The dry ice will replace O2 with CO2. No worries on the inside of the tank. I have seen it done numerous times.
 
An oil tank retrieval team were working on a property down the block removing an oil tank, so I went to the boss and asked him how much to take my de commissioned above-ground tank away while they were around. He quoted $200 so we had a deal. It took minutes to bring in the excavator and take it away. They used a large grinder with a cutoff wheel to cut it into sections and the small amount of fuel inside caught fire. The chap didn't seem concerned and he told me that the fire would smother itself, which it did. So it seems even cutting out your old diesel tank is not without risk of fire! BTW that 35 year old tank was in still in excellent condition.

ImageUploadedByTrawler Forum1447521341.258397.jpg

When we were looking at purchasing the subject of tanks came up and one On my my commercial fishing buddies told me not to worry about it as welding fuel tanks is done all the time. I got the sense that few of these guys spend money replacing tanks.


Jim
Sent from my iPad using Trawler Forum
 
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I worked for and am still close enough I may go back in the spring, for a company that made a fortune in removing underground heating oil tanks for the last 15 years or so.

While they are careful and haven't had any fires/explosions, they follow the basic rules but no way close to what some people would belive is necessary in dealing with, cutting up or repairing diesel fuel tanks.
 
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