Replacing original black iron tank

[Scubaseas]

Look up "tank sealing system' POR 15 is a good one. KBS is also good. There are several epoxy products. There is also rubberized sealers like Red Kote. I have used all three of these over the years on different vehicles.

I've also cut up tanks. Angle grinder with a cutoff wheel or a sawzall with a good bimetal blade works. Tank maybe too thick for an air chisel panel ripper. Pneumatic nibbler works great to OK depending on tank gauge and is a lot quieter than an air chisel.

[Bill Seal]

I finally found a manufacturer of aluminum tanks, RDS manufacturing. I don't think they sell directly, but Tank and Barrel (look it up) appears to be a dealer. They have many different sizes and types. A typical 30 gal tank is less than $450, including sender.
Now all I have to do is cut out the bottom of my cockpit to get the old one out.

[drdoyle]

To do a proper fix you have to remove the tank from the boat. However difficult that may be. Sand blast it, fill with inert gas and weld as necessary. Even cut out and replace plating if required. At this point i would epoxy zinc coat it and then epoxy glass (heavily) the tank. If you do it yourself you can probably get by under 1k$, but a professional boatyard repair could easily hit 10k$. The joys of boating.

[phorvati]

Since I already cut out and removed the baffle, I am not reusing the old steel tank. I might remove remaining walls of original steel tank and get two smaller tanks made that have fittings made to link them so they are as one. Then just have 1 set of hoses where it's accessible and have inspection ports and drains for each tank.

So I still need to make mockups of both tanks. I guess they can be linked via two 1.5" fittings. One at top one near the bottom. Might not even need baffle then

[Shaneesprit]

Get a Brave ( extremely good ) welder to weld a patch on the tank while it’s full of diesel - The diesel will not burn if the tank is full - seen it done on a 1 inch pipe where they forgot to weld the entire joint and the tank was full with about 6000L of fuel. He crawled down the back of the tank laying in the diesel, very cramped could only see his feet, guys a legend.
If the welder cannot weld looking in a mirror then they can’t weld! - welders top tip

Of course if depends on if it’s worth salvaging the tank, JB Cold weld Epoxy would also work, Never use Silicone that stuff feels nice and soft but it’s more like diamond dust and destroys engines if it dissolves.

[col50]

Originally Posted by phorvati

Now that i think about it, that entire bottom corner on the outside has been probably soaked in diesel. Outside along the bottom there is fiberglass tabbing and tank was rusting from outside as well. So diesel/water was soaking between the rusty tank on the outside and fiberglass tabbing. But I emptied that tank and whatever was left in it in 2017 and its been empty every since. I can still see potentially that igniting as I go to weld it on the inside.

Most likely, the entire inside of the tank is rusty, and you can't weld rust.

[Bill Seal]

Back to my leaky tank, I think I'll either cut into little pieces and get it out, or open it up and mount a smaller aluminum inside the carcass. The boat has a Volvo MD11c, burns less than 1/2 gallons per hour. Is there any reason a 26 gallon tank wouldn't work instead of the 55 gallon the boat came with.
After all, Catalina is only 26 miles away.

[Scubaseas]

I have an MD11c in a 13000# 32' Pearson323. The 30 gallon fuel tank can easily go 250 miles.

[mjscottinnc]

I’ve got an MD11c too, burns 1/2 gal per hour averaging 5.5 knots (slack water), my Pearson 323 with 30 gal tank get me 325 miles.

[Bill Seal]

Originally Posted by mjscottinnc

I’ve got an MD11c too,.

I feel your pain.

[Scubaseas]

Originally Posted by Bill Seal

I feel your pain.

Sorry to the OP for thread drift. I converted my MD11c to freshwater cooling and a dual 13mm V belt pulleys over 28 years and 2200 hours ago and have had zero problems but for a dirty fuel filter. Once. So yeah they're terrible motors. Completely unreliable.

[mjscottinnc]

Originally Posted by Bill Seal

I feel your pain.

It’s 40 years old and still kicking, all in all no complaints.

[Bill Seal]

I never said they weren't great engines, from what I've read, they're some of the most reliable, but if you forget to put the MSB transmission in reverse when sailing, and burn out the clutch, good luck finding another input shaft. And, they use an odd-ball coupling, so you can't use any other gearbox.

[Scubaseas]

You can reline the cone clutches. You may still be able to buy new gears but the last one I got was pricey. Nice packaging though.
You can get an adapter plate made to refit a different box if you can't fix your MS. The bell housing pattern is a standard SAE # something or other. I can't speak to the coupler as I have a Walther V drive on mine.

Maybe we should move this off this thread. Sorry phorvati.

[phorvati]

For those that want to consider patching the tank....i managed to get the first half of my tank out last night. It's worse than it looked. Those are cracks along the top corner where I never imagined it would be rusty. It was being masked very well. So repair would have never worked for my case.
I guess inspection needs to involve an ice pick and a hammer probing every corner