Hi Mike,
I got your PM about the survey and sea trial, but also saw your thread here, so I figured I would answer your question here so others can chime in.
In general, after 10 years of ownership, I like my 400, it's a solid boat with both good and bad qualities. It's a very good value but not made to cross oceans (more on that later). I think I am pretty pragmatic about my boat, but probably have a few blind spots in regard to it, as do most of us on here.
As far as specifics to look for in the survey, my list is below. It is by no means comprehensive, just the main things I can think of off the top of my head.
1. Check the flybridge deck in general for core rot. Specifically, look around the base of the rail that surrounds the access cut out to the top of the steps leading down to the cockpit. Especially the furthest forward base. Also check the bases of the FB table legs. Those are areas where Mainship screwed directly to the deck with no backing plates on earlier models. My 2005 has backing plates under the table but not under the rail bases. Those spots need to be addressed with proper bedding.
2. Check the transom where the below waterline bolts for the swim platform come through. I have heard that some boats see rot there, again from improper bedding.
3. Check the core of the swim platform for rot. Also check the boarding ladder, it's surprisingly expensive to replace.
4. The ER vent on the stb cabin side is likely rotted out. It's an expensive ($900) item to replace. I had one fabricated from stainless for less.
5. The head hoses, if original, will likely need replacement. The hose leading from the toilet to the vacuum generator is tough to remove.
6. Exhaust hose is likely ready for replacement. Not sure how hard this is on a single, but this is a tough job on a twin.
7. If the genset is in a sound shield, look closely inside at the genset for rust issues. If you buy the boat take the sound shield off and throw it away.
8. Look closely at the caulk around the FB steps. It can fail and cause deck rot.
9. The huge FB seats are super comfy, but the cushions are expensive to recover. Have they been stored on the FB or below?
10. The vinyl on the walls in the FWD cabin is prone to flaking. It's a big job to replace it. Same for the headliner, but not as hard to replace.
11. Mainship's wiring practices were overly complex and not very neat.
As far as ride goes, it is about the same as any other 40' unstabalized trawler. When the 400 came out there was a line of thought among 390 owners that it was more prone to roll than the 390. I do not think this has much, if any, merit.
I have a close friend who we cruise with often who has a Grand Banks 42. I don't notice much, if any difference in the ride of our boat verses his. We had a Gulfstar 36 before our 400 and the Mainship rides much, much better than our old boat did.
We have crossed the gulf stream to the Bahamas (and back) 28 times. We have also crossed the tongue of the ocean, plus multiple other open water Bahamas runs and have crossed the upper Gulf of Mexico from Carrabelle to Tarpon Springs 6 times. So plenty of open water trips.
We pick our days, but sometimes you still get caught out in it.
In May of 2021 a cold front sagged down lower and much faster than any of the four models forecasted it would and caught us in the middle of the stream. In about 3/4 of a mile conditions went from 5 knots SE with 1-2' seas to 35 knots from the NE and 6 to 8 with very little direction and a tiny period. It was the worst conditions I have seen, despite a background as a fishing guide, commercial grouper fisherman and commercial shrimping. The oven came open and a glass tray fell out. The TV didn't come off and we didn't break any dishes other than the tray. It was not comfortable and I was happy to see the inside of the St. Lucie Inlet, but the boat handled it OK.
I will say this though, in my opinion it is a much better boat when equipped with twin engines. When it gets rough we bump up the speed to 12 to 15 knots. The boat rides smoother at that speed, a lot smoother. Also, the extra power helps in following seas because you can work the throttles to control the ride.
It's not a sportfish or a Nordhaven and shouldn't be mistaken for one, but it's not some unsafe inland only boat either. It's a great Bahamas and ICW boat, but I wouldn't choose it for a trip deep into the Caribbean.
I'm not sure where or how you could mount a gyro in a 400. Maybe in the LAZ? It would take up a lot of space, be expensive and would likely require some reinforcement. If you are facing lots of rough water and are set on a 400, I would advise you to consider a twin over adding a gyro.
I hope this hasn't deterred you, as I said on the whole I really like my boat.
Happy to answer any other questions you may have. Good luck with the survey.
Doug
