Beneteau 361 Grid/Matrix Separation

[C420sailor]

2001 B361, on the hard. Was doing a hull strip and re-barrier/paint, and replacing all thru-hulls. Pulled the galley sink drain thru-hull and noticed a void between the internal liner and the outer hull. The thru-hull must have been clamping them together. Weird.

Anyway, I started pulling the keel bolts one by one to check and clean them. Pulled the aft one and noticed what you see in the pics.

I’m afraid that the lack of clamping force from the thru-hull and the aft bolt put the bonding in tension, causing separation.

At a loss here. Not sure what do. These pics are of two adjacent bays—the one containing the aft keel bolt and the compartment immediately aft of that. Please advise.

https://imgur.com/a/qSrd4DI

[Dockhead]

Boat is held together by a through-hull fitting? That's crazy. Sorry, but big picture -- that is not an acceptable structural system. If I were you I would fix it and sell it quick.


To fix it -- you need a qualified shipwright. Nobody here can tell you from those photos what (if anything) can be done. Just as a wild guess -- I would think that that structure could be glued back together again somehow. But I wouldn't keep it after that.

[kenbo]

The crack going up from one of the limber holes indicates impact/grounding damage to me. It's clear that the grid is no longer attached to the hull in the areas you show.

And the mismatched paint(?) colors in the bilge indicate someone knew the problem and tried to hide it or did a lick and a promise fix.

[Marathon1150]

I would certainly start with a professional assessment of the extent of the problem, repair options and estimated costs.

[C420sailor]

Yeah. When we bought the boat, the surveyor didn’t catch the paint. I thought the guy repainted the bilges to keep the boat nice.

It’s painted in that part of the bilge all the way forward....

He clearly just painted over the cracks.

I want to find who did this and beat him within an inch of his life. I’m beyond furious. I’m seeing red.

[kenbo]

I can feel your anger but it's time to get critically thinking. I'd start by fully assessing the extent of the liner separation and checking to see if there is any delamination of the hull by the aft end of the keel. Depending on your skill and experience level that might be left to a professional fiberglass specialist.

But the pictures shown dictate at a minimum retabbing the grid to the hull. It's a VERY dusty and nasty job. Avoid the temptation to simply insert epoxy into the cracks and break out the paintbrushes.

[Marathon1150]

Originally Posted by kenbo

But the pictures shown dictate at a minimum retabbing the grid to the hull. It's a VERY dusty and nasty job. Avoid the temptation to simply insert epoxy into the cracks and break out the paintbrushes.

I have posted elsewhere that one of our boats had a similar problem because of a hard grounding. As quoted above, it is a very dusty and nasty job. The professionals who did the repair removed everything from inside the boat, "bagged out" the interior, and then ground away the areas of delamination. And then rebuilt it. It is now as good as, or according to some, better than new. It cost the insurance company about C$60K, which was about 95% of the boat's value at the time. I asked the insurance company, before we moved ahead with the purchase, why they did that. They answered that the original estimate was much less but as repairs were started, more damage details were revealed, and it was eventually too late to stop. And they had great confidence in the three different shops doing the work.

[kenbo]

Originally Posted by Marathon1150

I have posted elsewhere that one of our boats had a similar problem because of a hard grounding. As quoted above, it is a very dusty and nasty job. The professionals who did the repair removed everything from inside the boat, "bagged out" the interior, and then ground away the areas of delamination. And then rebuilt it. It is now as good as, or according to some, better than new. It cost the insurance company about C$60K, which was about 95% of the boat's value at the time. I asked the insurance company, before we moved ahead with the purchase, why they did that. They answered that the original estimate was much less but as repairs were started, more damage details were revealed, and it was eventually too late to stop. And they had great confidence in the three different shops doing the work.

Was there any hull delamination at either end of the keel?

[JPA Cate]

IMO, you need direction from Beneteau. If it is not reparable, strip, piece it out, sell or recycle whatever can be done, and take the cut up pieces to the dump. It is a sad ending to a dream, no wonder you feel angry--any of us would feel furious. But if Beneteau cannot even tell how it must be repaired...well, you wouldn't want to sell it on, not fixed properly. Could cost someone the lives of their kids, or their own.

Sometimes doing the right thing is expensive.

Ann

[Marathon1150]

Originally Posted by kenbo

Was there any hull delamination at either end of the keel?

The hull did not delaminate but the liner was apparently separated from the hull. This was all done a year or two before we bought the boat but I have the detailed insurance survey and the 25 or so pages of invoices providing details of what was done to fix the problem.

During the pre-purchase survey the surveyor and I opened up the salon to examine the bilge. It looked brand new on a 1990 boat. It also had stainless keel bolts and nuts which is not standard from Beneteau and they also looked brand new. We questioned the owner about the keel bolts and he replied that "the originals were showing some rust so they were replaced". I don't doubt that they showed some rust, but that is not the main reason that they were replaced. We found out those details from one of the shops that did the work and then the insurance company.

[more]

Originally Posted by C420sailor

2001 B361, on the hard. Was doing a hull strip and re-barrier/paint, and replacing all thru-hulls. Pulled the galley sink drain thru-hull and noticed a void between the internal liner and the outer hull. The thru-hull must have been clamping them together. Weird.

Anyway, I started pulling the keel bolts one by one to check and clean them. Pulled the aft one and noticed what you see in the pics.

I’m afraid that the lack of clamping force from the thru-hull and the aft bolt put the bonding in tension, causing separation.

At a loss here. Not sure what do. These pics are of two adjacent bays—the one containing the aft keel bolt and the compartment immediately aft of that. Please advise.

https://imgur.com/a/qSrd4DI

Remove grind gelcoat, topcoat in all area in picture. cut some part keel bolts unscrew, protect with wrap. put 3-5 layer glass rowing and mat with vinyl ester (or polyester if budget is low) sand, put epoxy filer,spray topcoat. sell boat.
Shipyard repair
first, remove keel
Remove grind Gelcoat, topcoat in all area from cabin to cabin 4-5 meter long
put glass,vinyl ester 6-7 layer
sand ,epoxy filler, topcoat spray.
under boat ver is keel coule layer glass and epoxy with filler. return keel
boat is stronger from day one but is weight 70+ kg

[C420sailor]

Plot thickens.

I’m a millennial, which means I take pictures of things out of compulsion.

I have a picture of the bilges on 4/5/21. Clearly visible is a hole where a thruhull is removed, so it was after removing the thru-hulls. It was a before pic, taken before I did the seasonal bilge scrubbing (figured it would be easiest to do with a nice hole in the bottom of the bilge, so I could use a hose!)

No cracking visible in the photos. I feel I would’ve remembered this cracking while spit shining the bilge...

The only things of note that happened between now and then:

-Boat was moved by boatyard to another spot on yard
-I removed aft keel bolt for inspection and cleaning today

Makes me wonder if it was holding on for dear life from an old poor repair, and it came down hard on the blocks? Or maybe the bolt was the last thing holding it all together?

[more]

Originally Posted by C420sailor

Plot thickens.

I’m a millennial, which means I take pictures of things out of compulsion.

I have a picture of the bilges on 4/5/21. Clearly visible is a hole where a thruhull is removed, so it was after removing the thru-hulls. It was a before pic, taken before I did the seasonal bilge scrubbing (figured it would be easiest to do with a nice hole in the bottom of the bilge, so I could use a hose!)

No cracking visible in the photos. I feel I would’ve remembered this cracking while spit shining the bilge...

The only things of note that happened between now and then:

-Boat was moved by boatyard to another spot on yard
-I removed aft keel bolt for inspection and cleaning today

Makes me wonder if it was holding on for dear life from an old poor repair, and it came down hard on the blocks? Or maybe the bolt was the last thing holding it all together?

watch this video and gay repair hit the ground new boat

https://www.youtube.com/watch?v=C3RzxLW7t1U

[Spot]

This all sounds like Expedition Evans all over again...

https://www.youtube.com/watch?v=JJ3MruoO2q4

[kenbo]

Originally Posted by C420sailor

Plot thickens.

I’m a millennial, which means I take pictures of things out of compulsion.

I have a picture of the bilges on 4/5/21. Clearly visible is a hole where a thruhull is removed, so it was after removing the thru-hulls. It was a before pic, taken before I did the seasonal bilge scrubbing (figured it would be easiest to do with a nice hole in the bottom of the bilge, so I could use a hose!)

No cracking visible in the photos. I feel I would’ve remembered this cracking while spit shining the bilge...

The only things of note that happened between now and then:

-Boat was moved by boatyard to another spot on yard
-I removed aft keel bolt for inspection and cleaning today

Makes me wonder if it was holding on for dear life from an old poor repair, and it came down hard on the blocks? Or maybe the bolt was the last thing holding it all together?

There is absolutely no way that the through-hull fitting was holding the liner to the hull.

I am fairly certain that the keel bolts do not go through the liner/grid, only the hull. So removal of those two elements should have no bearing on the hull to grid separation.

If you have photo indication of no problem prior to the boatyard move then it may be that they either: 1) set her down too hard or 2) misplaced the keel blocking.

But none of that removes my suspicion as to why the bilge is partly painted in the damaged area. You may not have noticed the separation due to the way the boat was blocked, i.e. the keel could have been pushing the hull up to the grid and closing the gap and after the move the jack stands may be supporting the hull and the keel maybe be able to sink due to improper blocking, soft ground or soft wood.