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newbie3 02-20-2019 01:39 AM

Benataeu grid construction
 
5 Attachment(s)
Hey guys, I'm looking for some buyer advice. I've found a 1980's Benataeu 37' sailboat that I really liked. After looking under every single floorboard and spending hours studying the hull I did find some signs of concern in the bilge. Some cracks around the edges. Not everywhere, but on a couple spots port side. Maybe superficial... I'm not an expert.

I already had a survey and haul-out scheduled... so I asked the surveyor to come early just to look at what I found in the bilge. Told him not to worry about anything else.. just please don't tell me it's a problem with a grid...

He came later that day and through sounding what he found was hull-grid separation. I cancelled the haul-out and survey.. informed the seller of the news... and I took a step back... but I'm still thinking about that Benataeu. This is the part where everyone here says.. RUN. DON't LOOK BACK. JUST RUN.

Is anyone here directly familiar with the 1980's Benataeus? Like the First 35, 11.5's, and 10.5's... What are the chances the grid is intact and the damage is superficial? Does it make sense to hire another surveyor and get a second opinion?

Attached are the images from the bilge where the surveyor chalked an X where he found separation/delamination through sounding while docked at the marina.

newbie3 02-20-2019 01:41 AM

Re: Benataeu grid construction
 
3 Attachment(s)
A few more photos from the survey.

newbie3 02-20-2019 01:43 AM

Re: Benataeu grid construction
 
2 Attachment(s)
And here's what I found in the bilge before the survey... Again, I don't know if this is superficial or has anything to do with what the surveyor concluded.

MarkofSeaLife 02-20-2019 01:49 AM

Re: Benataeu grid construction
 
I don't see the problem.
You did the right thing and had carefully inspected your prospective boat then ensured the surveyor inspected and reported on it.
That's the idea of using a surveyor.

Well done and happy hunting for the next boat. :)


Mark

newbie3 02-20-2019 02:08 AM

Re: Benataeu grid construction
 
I suppose more specifically, I'm trying to find out if there's anything worth investigating that can put some doubt on the results. Or are these results concrete?

Is this a sign that the stringers and framing are destroyed? Or could they be intact and the bones are still solid?

Any chance what the surveyor found as delamination is only cosmetic? Or is there no doubt that this sailboat is no longer fit for use?

cb32863 02-20-2019 09:14 AM

Re: Benataeu grid construction
 
Quote:

Originally Posted by newbie3 (Post 2051584552)
I suppose more specifically, I'm trying to find out if there's anything worth investigating that can put some doubt on the results. Or are these results concrete?

Is this a sign that the stringers and framing are destroyed? Or could they be intact and the bones are still solid?

Any chance what the surveyor found as delamination is only cosmetic? Or is there no doubt that this sailboat is no longer fit for use?

Sounds like you are trying to convince yourself that it would be OK to buy this boat. There are lots of boats out there. I doubt that this is a specific Bene issue. While people can chime in on your pictures, none of use are actually there as your surveyor was. That's what he gets paid to do, I would go with what he said as he was on the boat. Keep looking, you will find the boat that works best for you.

svHyLyte 02-20-2019 09:19 AM

Re: Benataeu grid construction
 
Quote:

Originally Posted by newbie3 (Post 2051584552)
I suppose more specifically, I'm trying to find out if there's anything worth investigating that can put some doubt on the results. Or are these results concrete?

Is this a sign that the stringers and framing are destroyed? Or could they be intact and the bones are still solid?

Any chance what the surveyor found as delamination is only cosmetic? Or is there no doubt that this sailboat is no longer fit for use?

Those are cracks in the gel-coat surface of the structural grid and will develop over time as the hull works. The more important issue is the integrity of the lamination between the grid and the outer hull which is intact. FYI, the structural grid is laid up as a solid element and then cut-outs are made between the ribs to allow access to the outer hull skin. The cut-outs are made leaving a "flange" on either side of the ribs that is then bonded to the hull with overlaid strips of glass as a continuous "tab" on each side of the ribs. The structural grid on the Firsts typically extends about 750 mm (≈30") above the bottom of the hull on either side and is bonded in place with an epoxy adhesive. The grids are/were put in place while the outer hull glass was still "green" (i.e. not fully cured) to allow both a chemical as well as adhesive bond creating a very strong and reasonably stiff hull structure. The hull does flex somewhat in a seaway, however, such that cracking in the gel-coat surface of the grid is not uncommon. It is a cosmetic rather than structural issue. (For a more detailed discussion of the construction method, refer to Ferenc Maté's, "The Worlds Best SAILBOATS" commencing on Page 42.)

Looking at your snaps, I suggest that the interstitial spaces (between the underside of the floor boards and the inner surface of the hull) could use a good cleaning (hot water, Dove dish soap and a [very] little bleach followed with fresh water rinsing) and thereafter routine maintenance. Gel-coat "touch-up" can be applied once the surfaces are cleaned properly if the cracks really bother you. (You can use some color additives to "tint" the touch-up gel-coat to match the original.)

Further, in one of the snaps I noted what appears to be a check-valve in a bilge pump hose, which is unwise. While the valve will prevent back flow into the bilge, it is an obstruction that reduces the pumps discharge rate and can become clogged or otherwise malfunction obviating the purpose of the pump itself.

FWIW...

newbie3 02-20-2019 11:23 AM

Re: Benataeu grid construction
 
Quote:

Originally Posted by cb32863 (Post 2051584584)
Sounds like you are trying to convince yourself that it would be OK to buy this boat. There are lots of boats out there. I doubt that this is a specific Bene issue. While people can chime in on your pictures, none of use are actually there as your surveyor was. That's what he gets paid to do, I would go with what he said as he was on the boat. Keep looking, you will find the boat that works best for you.

I think to me it's more about doing research and learning so I'm a better informed buyer in the future. Also, I'm skeptical of everything :) I've had plenty of experts give me bad information. Not that I suspect the surveyor did... This is more of a follow-up and curiosity...

You're right about the photos. But pictures are better than nothing. And I'm hoping someone here looks at them and say...

"Oh - yes, I've seen this pattern before. These are the common structural weak points on a Benataeu grid."
Or..
"Well, that area doesn't make any sense.. hull separation happens here and here and not over there."

newbie3 02-20-2019 11:41 AM

Re: Benataeu grid construction
 
Quote:

Originally Posted by svHyLyte (Post 2051584588)
Those are cracks in the gel-coat surface of the structural grid and will develop over time as the hull works. The more important issue is the integrity of the lamination between the grid and the outer hull which is intact.

Ah okay. I really wish it was easier to see exactly where the grid is joined to the hull.

Quote:

Originally Posted by svHyLyte (Post 2051584588)
The structural grid on the Firsts typically extends about 750 mm (≈30") above the bottom of the hull on either side and is bonded in place with an epoxy adhesive.

So you're saying that direct grid delamination occurs at a specific height? I think some of the surveyor markings appear much lower. Can delamination appear in such a way where the grid is still intact and joined to the hull? Or is any delamination a sign of a system wide failure and it doesn't mater where you find it?

Scotty C-M 02-20-2019 11:57 AM

Re: Benataeu grid construction
 
Have you talked with anyone in the Benataeu organization about this? While my original thought was that this was a big problem, I am also interested in HyLyte's idea that this is superficial. It does make sense. I think that finding someone who is well educated on the design parameters of this build would be helpful, hence the idea of calling up Benataeu.


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