reinforcing cockpit benches

[Cevin c Taylor]

Hello all.  While using my '83 CP 16 on Saturday, I noticed a crack in the starboard bench seat in the cockpit.  There is also cracking on both sides where the bench seat meets the coaming (sp?), right in the intersection.  I had assumed that the cracking was just in the gelcoat, but the crack in the seat surface seems to possibly go through the fiberglass.  I notice that the bench seat flexes a lot when I have to step on it.  I'm not a huge buy - about 180 lbs.  I can press on the area around the new crack and make the seat flex, and I think that if I stepped on the area around the crack, it might go through the fiberglass.  I'm thinking that I need to go beneath the bench and shore up the seats to stop the flexing before trying to fix the cracks.  Has anyone else had to do this?  Any suggestions on how to go about it?  I was thinking of taking some 1/2" or 3/4" plywood and putting it under the seat, and then building a frame underneath it.  I might someday use the berths for camping, so I don't want to interfere with that area any more than necessary.

[MacGyver]

I cant speak for a 16, but on our 19 I have the same issue (if I have read it right) at the area where you would go to enter the cabin and the seat mates up. so companion way/seat?   what I have noticed (again, cp19 here) is the cracks are in fact in the gelcoat, and when I step in the companion way area as if I am going to go into the cabin, I notice it drops a little.
You can hear it by the creaking of the wood on wood contact of our entrance step.

Looking at it all, (this is my boat technician side talking now) I see only 2 ways to solve it, reinforce and carry the loading out of that corner by adding layers of glass and running them all different directions, or adding a brace down to the floor.

The brace is obtrusive to the openness of that area, but the reinforcing isnt......

From the tech side, the gelcoat will crack to show the stress there, but that doesnt meant it is thru the glass, unless you grind it out and find that it is indeed in the glass.
Adding glass should indeed stiffen the area up and make it less prone to movement, but you also move the point of stress.

I havent seen the inside of a 16, otherwise I would offer more of a opinion, but (if read right) I beleive I have the same issue on our 19.

Mac

[Cevin c Taylor]

Thanks for your input - very helpful.  My cracks are actually running parallel to the gunwales - they are at the base of the gunwale where it intersects the bench seat.  They are on both sides, but the starboard side is the worst one.  Bracing underneath with wood would be unobtrusive, and I think that if I did it right, it would not interfere much with legroom when you are lying in the berths.  I'm going to try to do something this week, since I'm afraid I'll step on it and damage it. 

[deisher6]

Hey Wolverine:
I was wondering if your C16 has a large foam block under the cockpit deck between the bunks.  I have the one in my boat wedged in tight to support my lard butt.

regards charlie

[Salty19]

I'm wondering the same thing as Charlie. A huge block of foam should be in the spot you described which helps to support under the cockpit.

[skip1930]

My CP-19 is showing it's use too. Stress cracks around the stanchions, those stupid never used pad eyes from the factory, a bit of the curve transecting from vertical to horizontal off the cock pit combing to seat. And that huge blue carpeted foam block was placed under the settees to help elevate that problem...not structural but darn unsightly. They do sell a crack filler which I have never had much success using...

I have often thought about replacing that block with a 6mm saw cut piece of aluminium Marine-Tex'ed to the bottom side of the seats with legs following the curve of the hull down. Also glued into place. This to carry the load. That would open up a huge stowage area under the cockpit.

skip.

[Cevin c Taylor]

There is no foam at all beneath the benches - if I look down the length of the berth, I have an unimpeded view all the way to the lazarette compartment area.  On the stock boat, how far forward does the foam extend so as not to interfere with sleeping space in the berth?

[Salty19]

Wolverine,  I'm sorry to say but the cracks are due to no foam or reinforcement. Prior owner must of removed them.
Gotta reinforce it for sure. I'm sure others will pipe in with ideas, but I'm thinking a crate-like box without sides under the footwell. Make it so you can store light stuff down there but still easy to access.

[Tim22]

Does this problem have any similarities to the Sun Cat? I notice that the side cockpit seats on my Sun Cat flex quite a bit when I step on them.

Tim

[jeffcom16]

I have had the same problem on my 16 and had to strengthen from underneath. The plywood was coming away from under the seat so I pried it away with wedges, drilled some holes in it and injected 5200 sealant. I also made some plywood supports running across the boat and fitted them up in between the foam, and curving just under the radius on the seat. I cannot speak more highly about the incredible strength and support you can get from 5200, and is much easier to use than fiberglass and resin........

[Cevin c Taylor]

I spent a weekend reinforcing the benches.  I first made cardboard templates of the underside of the benches, and then I cut plywood sheets using the templates.  The sheets are about 48" long.  I then made frames from 2x4's - a horizontal piece perpendicular to the length of the boat, and supported on each end by a vertical piece of 2x4.  I put three supports on one side, but only two on the other (because I used thicker plywood there).  I went sailing last weekend at Houghton Lake in central Michigan (largest inland lake in the state), with my two sons and one of their friends.  Each of us weighs 180-190.  The benches held up fine.  We were walking all over them, and I didn't notice much flexing at all.  I'm very pleased with how it turned out.  I might add one support to the side with only two.  I only wish I had extended the plywood a little farther forward. 

On our sail, I was surprised at how well the boat accommodated the four of us.  It was a bit tight when all four were in the cockpit, but doable.  Often one of the boys was up front on the forward deck.