Mainship 400 Trawler Swim Platform Rebuild

[Mermaid]

This, from my significant other who pulled the platform off our 2006 400 Trawler to repair the splitting fiberglass from the underside...wow...the gremlins he found in the production of this platform which will ultimately plague all 400 Trawler owners whether you know it or not - kind of like the swim platform of 390 owners, but their production flaw is way greater.

There are many of us who will say, “We’ll just pretend we didn’t see that,” and a few will repair it. I want to be one of the ones who claimed we didn’t see it, but being who I am...I saw it and am having Captain Ed rebuild this to include a new ladder. Initially, we though we could save the original ladder - it was a good one - but there as so much salt intrusion and resultant corrosion, that we’re going to buy a replacement. It had a great run....great ladder, and we want another one just like it.

Ed says, “The swim platform on our 400 has some issues. The factory used aluminum plates, glassed into the platform as hard points for mounting the ladder and where the platform bolts to the back of the boat. The issue is that cracks develop, or sealant fails and water intrudes into the area where these pads are and corrodes the aluminum, which expands, creating more cracks and more water intrusion. I'm taking lots of photos and will share them as I go along. I believe all owners of these boats will face this situation eventually.”

A lot of wet plywood. Given that the boat was built in 2006, I would have expected coosa board rather than plywood, but plywood is a lot cheaper than coosa, and these Mainships were production boats not weighing heavily on quality or intelligent engineering. I’m not knocking that, just stating the obvious, and all of us should keep an eye on things, the swim platform being one of the things low on the list, really.

I love my 400 Trawler with all her many flaws. Ed and I have dug into a lot of boats with grinders, drills, saws and hole saws, and I can say that Mainship boats have been disappointing while at the same time rewarding.

That said, I own one, and I love her for her intended purpose, but she’s not a high quality boat. She is what she is, and I do like her for what she is. We will continue to make her better than Mainship meant for her to be.

 

[Comodave]

Sorry to hear about the problem, but it will interesting to see how you fix it all up. Keep posting, please.

 

[Dougcole]

Thanks for posting.


Interestingly, when I was swimming last month I noticed a thin (maybe 1/32") crack along the trailing edge of the platform, on each side of the swim ladder. No evidence of water intrusion or any other cracks under the platform though. I mixed up some thickened epoxy yesterday and filled the cracks. Then I got on TF today and saw this post. I'll keep an eye on the underside of the platform.


Having this repair be on the underside, out of sight, makes it a lot easier to deal with. I assume you are still hauled out? Are you going to glass in aluminum again or something else? Maybe solid glass and through bolt the ladder?



Agreed on the coosa (or similar) board over plywood. I don't like wood anywhere on the exterior or core of a boat. Most trawlers in this price range have either Balsa or plywood cores though, I'm not sure it is a sign of poor quality relative to other boats in Mainship's class, but they could have done better.



Also interesting to me to see the variations in failures on these boats, they are not all the same. I have not had the issues with core rot that seem to have plagued others (fingers crossed) though I had a fuel tank start to leak. I like to hear about issues like this so I can address them before they become a problem.

 

[TrawlerAJ]

I'm planning some open heart surgery on my platform as well, probably next winter layup. PO installed davits on platform and, of course, just drilled right through. Would love helpful hints and progress pics!



How well was the platform attached to the transom? Thinking about splitting the platform off the transom keeps me up at night.

 

[Comodave]

Maybe use G10 instead of aluminum for the backing plate.