I went through replacing both tanks on our Mainship 400 last spring (there are a couple of threads about it for those of you who care to look.)
It's interesting to compare the pros and cons of replacing the tanks vs having a professional repair done by someone like Triton. Both options have merits and neither is easy or cheap.
I called and spoke with Triton and found them to be professional and of high integrity. He told me they could do my tanks, but that it would be expensive, along the lines of what E-Sea paid, except I needed both tanks done, so almost twice as much.
The cost to work with Triton was just too high for me, though I think they do great work. In the end he advised me, given my situation and ability to do a lot of the work myself, to replace my tanks and not use their services.
I ended up cutting my main salon floor for access and replacing both tanks. It was a BIG job that required removal of both motors, batteries, exhaust hoses etc. I pulled the port tank intact, but cut up the stb tank to get it out. The new port tank is the exact same size as the original, but I lost 20 out of 150 gallons on the starboard side. I did the port side first, before I knew as much about the best way to do the job. If I had to do this job again (God forbid) I'd cut both tanks up to get them out and install the slightly smaller tanks on both sides.
I did most of the labor myself, with help from the yard where needed. That saved me a LOT of money, though it was month's worth of hard labor. I also used my mechanic to prep the motors for pulling and to re-install and align them after they were back in.
All in, I spent $12,500 for both tanks and everything associated with the job except the cost of the new Lifepo house bank.
Some notes:
There are some big not so obvious advantages to pulling the tanks and replacing them with new tanks.
I installed sight gauges on the new tanks.
I now have new tanks, built and installed better than the original Mainship tanks (see note below). I used TNT in Fort Pierce, they did a great job and my new tanks are beautiful.
With both motors out I was able to clean and paint the entire engine room (turned out great).
I was able to improve wiring issues due to easier access.
With the motors sitting in the yard, I gave them an extensive strip/degrease/repaint job, replaced hoses etc.
I replaced my motor mounts on one side (other didn't need them).
Mainship tanks are thinner than the industry standard and at least in my case, poorly installed. They sit too close to the deck which causes corrosion. In my now educated opinion, virtually all 2000s era Mainship owners are going to face tank leaks in the next five years or so, if they haven't faced them already.
There are some disadvantages too.
It was a lot of work. If you can't do some of the labor yourself it may be similar price to have a company like Triton repair the tanks.
My floor is cut. It doesn't look bad, most of the seam is under the couch, but you can see it. At some point I may repalce my synthetic teak flooring to cover it, but I'm good with it now. I reinforced the floor, so sagging is not an issue.
If you do a tank replacement the job is more of a worm can, one thing leads to another and you end up doing most of a refit in your ER.
Anyway, OP, I'm glad your tanks turned out well. The pics look great.
Doug
