390 deck joint

I was reading on the Mainship yahoo group about water coming in the boat thru the deck- hull joint. Apparently it was not sealed at the factory, they just put a bead of silicone under the rub rail as a seal, which fails over time. Is that an issue with you MS owners on this forum? Also, can someone tell me is the joint thru bolted, rivited or just screwed toether? I hope to buy one next summer and trying to learn as much as I can about the boats. Both strengths and weaknesses.

Thanks all

The hull and deck/cabin piece are held together with the rub rail. Mine has 5200 between the two flanges, the rub pushes onto the two flanges and holds them together, 2" SS screws are run into the rail and flanges horizontally, white drywall style screws are run down through the top of the rub rail and through the flanges then a SS rub rail covers the outside perimeter of the rub rail to finish it off.

Water intrusion comes in where the top of the rail comes in contact with the top deck/cabin piece, flows inside where the 2" screws run into the joint. I had wet core (yes they cored the corners with balsa) removed at the aft corner. The moisture pattern flowed perfectly from where the 2" SS horizontal screws came in.

To seal it the factory ran silicone around the top edge of the rub rail where it contacts the top deck/cabin piece. I removed the rub rail completely, cleaned it out and ran a bead of boat life around it then push the rail back on and screwed it back. I notice that the factory installed 5200 was inconsistent and had gaps. Thus the stories about the problems the factory trying to assemble the top half and bottom with wet sealant on the flanges. But the water was entering from the top and going in where those 2" horizontal screws were run into the rub rail.

It's all dry now. The repair to the aft corner was not cheap. It's the only place that is cored on the hull piece.

Thanks David, thats good info. So if I go look at a 390, what would you advise I look for in an initial look see?

I have a 2003 390 and had heard about water intrusion at the rub rail. Mine did not have any water coming in , but, I noticed a gap in the caulk around the top of the rub rail. I dug out the old caulk (clear silicone) and re-caulked. You should be able to see if there is an intrusion problem by looking at the sides of the boat from down in the generator compartment
John

No problems with our 1997 MS 350, hull #32. I think the factory was a little more careful with the earlier builds as far as QC goes.

No problems with our 2003 MS 390, hull number in the high 300's.

The Hull-Deck joint appears finely finished and fitted tightly, no gaps and no sealant showing.

Pluto said:

I was reading on the Mainship yahoo group about water coming in the boat thru the deck- hull joint. Apparently it was not sealed at the factory, they just put a bead of silicone under the rub rail as a seal, which fails over time. Is that an issue with you MS owners on this forum? Also, can someone tell me is the joint thru bolted, rivited or just screwed toether? I hope to buy one next summer and trying to learn as much as I can about the boats. Both strengths and weaknesses.

Thanks all

Click to expand...

May want to poke around other owners to see if they ever had any problems with being picked up by a travel lift.

Say a relatively new Mainship get picked up with the sling near the deck fills and the sides flexed enough that the deck cracked though at least one, maybe both fills.

The yard was flipping out and he owner yelling right back...not sure how it was resolved but it had plenty of people scratching their heads...

Any warnings where to or not to place slings?

Sling placement is clearly marked. We have never had an issue with haulouts, and we have one of the first boats. (#32). We get hauled every year for winter storage. Could it be that the travel lift being used for the boat that had issues maybe was too small? The 350/390 is quite beamy at 14'2" If the slings are not angling away from the boat, this could be a problem.

ronlord said:

Sling placement is clearly marked. We have never had an issue with haulouts, and we have one of the first boats. (#32). We get hauled every year for winter storage. Could it be that the travel lift being used for the boat that had issues maybe was too small? The 350/390 is quite beamy at 14'2" If the slings are not angling away from the boat, this could be a problem.

Click to expand...

For all I know it was a freak accident.... although there didn't seem much deck after the fuel fills were cut into them on the model that had the issue.

It was a 75 ton lift so it was plenty big enough as it routinely hauls up to 75 foot commercial boats.

Just a note worth checking into for current or prospective buyers.

psneeld said:

For all I know it was a freak accident.... although there didn't seem much deck after the fuel fills were cut into them on the model that had the issue.

It was a 75 ton lift so it was plenty big enough as it routinely hauls up to 75 foot commercial boats.

Just a note worth checking into for current or prospective buyers.

Click to expand...

You sure this was a 390? The fuel fills are on the side of the boat, not on the deck.

No...I'm sorry I'm not positive of the model or year....

I know it happened at least a few years back and I'm not commenting on overall quality. Just that I saw this happen to one of the newer Mainship trawlers and have seen hoisting issues with other models of boats that owners should be aware of... if it's anything but a freak accident. It could be a freak, boat specific, model specific, year specific, series specific.......I really can't say is because I never followed up on it.

I owned/lived aboard a Silverton Convertible for 7 years and showed plenty of people the boat was built just fine (systems weren't) and a heck of a lot more affordable than theirs.

Every boat I've owned has had the sling locations clearly marked on the hull, just below the rub-rail. I don't think I've seen any boats made in the last 40 years that weren't similarly marked. If a lift operator damaged the boat by failing to locate the slings properly, I'd say they were liable for the damages.

For my 2003 Mainship 390, I also found the sling locations in the owners manual.

Riverguy said:

Every boat I've owned has had the sling locations clearly marked on the hull, just below the rub-rail. I don't think I've seen any boats made in the last 40 years that weren't similarly marked. If a lift operator damaged the boat by failing to locate the slings properly, I'd say they were liable for the damages.

For my 2003 Mainship 390, I also found the sling locations in the owners manual.

Click to expand...

Not true...many aren't marked and if they were at one time...many have had the little tags crack or corrode and fall off....

In the last 40 years I have owned 3 large boats and none have sling marks....

I probably help in hauling at least 100 boats a year.

Even if marked...the sling operator still usually asks the owner for sling placement as they don't know of aftermarket transducers or any underwater appendage that could be damaged.

Besides..the one boat I saw damaged probably WAS hauled at the sling marks...still broke....

I always worry about the guys that different marinas use to haul boats along with their experience. Mainship built more trawlers than any other builder, so therefore more Mainships are launched each year than any other trawler builder. So if there was an issue with the boats this site and the Mainship Yahoo site would be loaded with complaints and there would have been a recall. They were pretty good at recalls when issues were found and would fix any problems that showed up long after the warranty period. That said, the marina we keep our boat was a Mainship dealer and the very first Mainship MS I was designed and built next door at the Cherubini plant and was launched on our travel lift. (as are all Cherubini's to date). So I always feel confident my boat will be hauled and launched correctly.
John
MS 390

Pluto said:

I was reading on the Mainship yahoo group about water coming in the boat thru the deck- hull joint. Apparently it was not sealed at the factory, they just put a bead of silicone under the rub rail as a seal, which fails over time. Is that an issue with you MS owners on this forum? Also, can someone tell me is the joint thru bolted, rivited or just screwed toether? I hope to buy one next summer and trying to learn as much as I can about the boats. Both strengths and weaknesses.

Thanks all

Click to expand...

Our boat is a sister brand, and I'd expect the deck-hull joinery is similar. We began having some water intrusion, traced to the rub rail, when the boat was approx. 8 years old. Relatively easy fix, pull the rub rail, re-caulk, put it all back together. (Knock wood.)

The problem could have simply been waiting to happen, or some lift slings... or I sorta suspect more likely from a hard-ish landing when a gust blew us up against the pile at a fuel dock maybe the season before we discovered the water issue.

(I still hesitate to approach a dock when 25-35 knot gusts would blow us right at it... usually try to lay up perpendicular to the dock at one end or the other -- when there's depth and clearance -- and then warp around the corner pile to end up parallel alongside the dock.)

-Chris