hull to deck joint separation

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hull to deck joint separation

Postby Guest » Sat Oct 02, 1999 12:00 am

This summer, while leading the last beat to the finish line in about 15 knots and with everything trimmed in tight, my foredeck peeled away from the hull, stopping only when it reached the bow cleats which were thru bolted ( kind of looked like Donald Duck with his bill open). The fiberglass actually tore perpendicular to the deck edge at each cleat. There was obviously alot of tension on the forestay and chain plate, and the chain plate was merely thru bolted to the deck (no hull - deck connection). When I examined the construction, I found that the deck was only glued to the hull, and that the adhesive/filler appeared to be porous and powdery. It was easy to scratch the adhesive with a fingernail. That adhesive was the only thing countering all the forestay tension. The boat is a 1986 Precision DS (13030), but the situation might apply to Day Sailers made by other manufacturers. Although my repairs have made the boat stronger than when new, the appearance has been somewhat diminished, and I would recommend prevention rather than repairs. To repair Little Petunia's nose, I rasped out some of the old adhesive/filler, dry clamped the deck back down and drilled holes thru the deck and hull joint overlap to accept 1/4" bolts (one at the bow, three others on 3" centers port and starboard). I released the clamps, lifted the "lid" and liberally applied 3M 5200 adhesive. Then I reclamped the deck to the hull, inserted the seven 1/4" stainless flat head machine screws and snugged everything down. I used finish washers under the screw heads, and fender washers and nylon lock nuts at the hull flange. The nose won't get out of joint again. Over all, the repair isn't too obnoxious, but my sweet Little Petunia now resembles "Jaws" from 007 fame. To repair the 3" long tears in the fiberglass, I plan to grind a V along the tear, fill with epoxy, fair it, and apply gelcoat. Anyone have any better ideas? Thanks.

Lee

Lee Peterson (leep-at-means.net)
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Postby Guest » Sat Oct 02, 1999 12:00 am

When I purchased my Day Sailer this summer it had similar damage to the prow. My boat is a 1981 Spindrift DS. My boat has a caprail all the way around the gunwale and has rivets connecting hull and deck through the rail, but the deck tore away anyway. I cannot imagine how the previous owner did it. Here's the fix. Your ability to do this may depend on your bow flotation tank arrangement. I would do this as a prventative measure if you can.

The chainplate for the headstay is attached to the deck with machines screws. I removed the nut from the aftmost screw and replaced it with an eyenut. For those who are unfamiliary, this is a loop of stainless steel that has a nut welded to it. It screws onto the machine screw from the bottom. You may need to replace the screw with a longer one of the same diameter to get enough thread. I would suggest that you use a nut on the machine screw ahead of the eyenut to make a lock nut.

I then attached an eyenut to the inside end of the towing eye.

I cleaned the hull/deck joint out as well as I could and bonded it with 3m 5200. Gotta love that stuff!!

I did not trust the 5200 to carry the load of the headstay, so I got some 5/32 spectra line and prestreched it. I tied the line off to one of the eyenuts and ran the line back and forth through both eyenuts to create a purchase system. Then I hauled it tight and tied it off. Lastly, I used cable ties to trap the line so that the knots cannot come loose, and even if they somehow do, the line will not slip.

So now I tension from the headstay directed in the the strongest part of the hull instead of the deck.

If you would like pictures, kick me an e-mail.

Justin

Justin Andrus (jandrus-at-mail.maine.rr.com)
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Postby Guest » Mon Nov 01, 1999 1:00 am

Justin,

Thanks for the info. Sorry it took so long for me to respond. I'd be interested in seeing the photos of your boat and your method of fixing the problem. I was thinking of using a turnbuckle to accomplish the job of tying the deck to the hull. I'll need to cut into the bow flotation area to get at the chainplate and bow eye, but that shouldn't be a problem. I doubt if the hull and deck will ever separate again the way it is now, but it would be nice to transfer some of the load from the chainplate to the hull. Hope you had good sailing this summer.

Lee

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Postby Guest » Wed Nov 03, 1999 1:00 am

Sorry about the delay in getting the pictures of my prow repair up. Law School is kicking my butt. I will try to do it this weekend.

Justin

Justin Andrus (jandrus-at-mail.maine.rr.com)
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Postby Guest » Thu Apr 05, 2001 2:02 pm

HI guys, I know that you posted this thread over a year ago, but I wanted to relate to you guys that I had a similar experience at the Daysailer Midwinters. My foredeck peeled back like a sardene can. I have a 1983 O'Day DSII, and again, the deck was only bonded to the hull, and the chainplate was only bolted to the deck. My chainplate has a toung that was also bonded into a space in the hull, but it wasn't enough. We fixed it by rebonding the hull and deck, and then adding three large bolts to secure the chainplate to the hull. It held for the rest of the midwinters, I haven't sailed much this year yet since, I will keep you posted

J.P. Clowes (jpclowes-at-hotmail.com)
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Postby Guest » Fri Apr 06, 2001 8:07 pm

Just have to jump in here:
I have a DS II 1980 vintage from Bangor Punta.
Bought it last year and on the third day out I suffered the same failure. The forestay is to deck plate which is backed up by a "tang" of brass which WAS bonded to inside of hull by some mysterious gloop that decided to give up. The deck raised by 3" but stopped where the deck is bonded to the airtank,, about 20" back from the bow. I repaired by opening an inspection port INSIDE, under the deck (my wife suggested that it was my call, but she would not cut a hole in the foredeck.). Ok, so I worked from under the deck and installed an aluminum strap... bolted to that mystery brass tang and then bolted to the back side of both bolts on the bow cleat. Also used epoxy and glass fabric to re-bond the deck to the hull. Repair now has the strentgh of the deck/hull bond and the metal strap to the bow eye. Several days' sailing since then, the repair is holding fine.

Good luck to anyone suffering the same failure.
Bob C.

Bob Cramer (RJCramer10-at-aol.com)
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Postby hectoretc » Sun Nov 27, 2011 7:48 pm

Greetings all,
I've seen mentions throughout this forum to a DaySailer hull/deck seperation issue under various conditions as referenced in this old post. This weekend I dropped a tool which rolled under the front of my boat. As I reached up for a handhold (on the boat) to support myself to recover it, I noticed a small crack (6 inches long) in the deck/hull seam on the starboard bow. I didn't think to take a picture (how could that be?) but will do so next time I'm there.
In meantime, I'm wondering how common these cracks are, how serious they generally are, and if it is prudent or overcautious to take some pro-active steps to strengthen the deck/hull joint hear the forestay stemhead. And if so, what is the generally accepted method(s) to do this?
Or do we need to wait for a picture for proper diagnosis?
Thanks - Scott
DS #6127 - Breakin' Wind - From the land of 10,000 lakes, which spend 80% of the year frozen it seems...
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Postby Alan » Sun Nov 27, 2011 8:25 pm

Scott,

Here's a recent thread on the topic.

http://forum.daysailer.org/forum/viewtopic.php?t=3561

I don't have any visible signs of weakness on the outside, but I plan to reinforce the area just in case.

I noticed in your mast sleeve photo on the other thread that there's an inspection port hole in your forward bulkhead. I'm curious about what you found in there. Do you have the L-bracket and goop that other people have found?
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Postby hectoretc » Sun Nov 27, 2011 10:23 pm

Alan wrote:Scott,

Here's a recent thread on the topic.

viewtopic.php?t=3561

I don't have any visible signs of weakness on the outside, but I plan to reinforce the area just in case.

I noticed in your mast sleeve photo on the other thread that there's an inspection port hole in your forward bulkhead. I'm curious about what you found in there. Do you have the L-bracket and goop that other people have found?


Thanks for the link Alan. I've read a couple postings (this one above is an example) where a fracture occurs in that seam, and the tension from the headstay can actually pull the foredeck up (like opening a can of sardines).
I'll get a better picture of that spot, but for the moment this shot from the day I brought the boat home points out where the crack is located (red arrow)
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This boat has suffered so many traumas (via previous owner) that I'd forgotten to comment on the crack across the foredeck as well. It has been mostly repaired (primarily from the inside) and I'd not given it much thought until just now looking at this photo, it probably has something to do with the deck/hull joint crack. It's very close to where the deck crack comes around the lip. - interesting... Anyway, I'll look at this whole thing again from that perspective.

Responding to your question about the access port in the bow bulkhead, in the same photo above, you can see that there was no boweye on this boat when I got it, so they had trussed it onto the trailer with a very bizarre rope configuration. Eventually I found the boweye hole (exactly behind the roller in this picture) so I put in the access port to replace the boweye. I think it was Talbot that suggested a U bolt version for which I found one on sale and grabbed it up.
As part of that repair, I pulled out 2 dozen little chunks of styrofoam in various stages of deterioration so I could get to the back of the boweye bolt. Like others, I found the 6 inch port was just too small to do much of anything having the same problem of positioning, getting your arm in, and then being able to actually do anything. Further, I found when pulling out styrofoam blocks that I came up once with a wasp nest. (how'd THAT get in there???). That ended my blind "sticking my hand in to see what I can find" exploration. I ended up putting an 8" access port on the bow deck, port side because of the repaired bow deck (Fore Deck?) on the starboard side. Fortunately there were no other nasty creatures in there. I think the bee's must've come in and made their nest at some point in the past via the nice little hole, also visible in the bowshot photo just above the bow roller on the starboard side (almost covered by the arrow). Said hole having been repaired as the result of another long forum discussion.
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In this picture you can see the 8" port (which fits perfectly inside the bulkhead) and then the mismatched gelcoat where they repaired the crack in the foredeck. 90% of the repair was on the inside which is the way to do it, and it seems very strong now. I can walk on it (and bounce on it) and there is no give at all.
Using that port, I cleaned out all of the remaining styrofoam blocks (a very large yard bag full) and now can easily get to the stemhead but can't really figure out what is going on there. There seems to be a small piece of wood (masonite or something similar) partially obscuring the bottom of the stemhead mount. I was sure I had a picture of that (via the port) but don't seem to have it in my computer so maybe not. I'll have to take another picture as I would like to get some opinions on why that wood is there, and if I can take it out to get to the stemhead backing.
Sorry for yet another long explanation, but as I said, this boat went through a lot before I got it, and I'm kind of adding my own havoc to the mix since I have this winter with nothing to do by modify and update. It is probably good that I couldn't just drop the boat in the water this summer when I got it home though. Lots and lots of important things to check first, and I never would have had the patience had it not been forced on me by winter. I have learned such a tremendous amount from everyone on this forum, and greatly appreciate the insights and patience for what I'm sure are some seriously dumb questions.
Last edited by hectoretc on Wed Nov 30, 2011 11:04 pm, edited 1 time in total.
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Postby jdoorly » Mon Nov 28, 2011 12:45 am

First I want to post a warning. The hull/deck joint, around the entire perimeter of the DS, varies greatly in the amount of deck surface area glued to hull surface. Looking at a length of sheer one would assume the curve of the deck matches and is joined to the curveed lip of the hull. But, only a small bead of glue bonds the last few millemeters of deck lip to hull. And the curves do not necessarily match or even meet! That is, on my boat, and I suspect on yours. Take a look at the joint from inside your boat and see...

That wasn't the warning, this is: Since there is space between the deck and hull lips- do not tighten fasteners in this area or you can break the glue bond at the lip edge!!!

When I installed new chainplates (because one pulled through the hull and lodged in the deck and left a 6' rip in the deck), I decided to use 9" long 7/8" thinwall stainless tubes that I had on hand and bolted the deck fitting through the deck to the ss tubes which fit wonderfully under the hull lip. A week later I noticed the side that hadn't broken now had an 18" crack in the joint. Then I checked the other side and found the same thing even after having re-glued the area with thickened epoxy. Luckily the repaired tear was ok. Now i have to untighten the bolts until the lips are parallel again and try to get some epoxy up in there. I can access the chainplate area from the interior so the job won't total pain.
DS2 #6408 "Desperado"
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Postby hectoretc » Mon Nov 28, 2011 10:27 am

Given what you've said about bolting or screwing the hull/deck halves together causing stress fractures, I'm curious how the original chainplates are designed to work. Perhaps the standard chainplate attachment points are either built up (in the factory mold) in the hull/deck assembly so those pressure points are not impacted by the tightening of the chainplate screws (in the narrow section of the factory backer tube). But that doesn't explain the chainplate failure on Desperado.

Jay, do you have a sense as to what caused the original chainplate failure? By your description, it sounds like the hull lip broke away, and at that point, the pressure was transferred to the deck lip causing it to pull up cracking the larger seam area?

My thinking would be as yours was, to use a longer tube to distribute the pressure over a larger area. But since that apparently put abnormal pressure on the hull/deck seam, perhaps the solution might be, to use several screws with the curved backing plate (1/2 of a tube to match the curve as you did) but to use nylon centered lock nuts, so the screw(s) can be tightened snug (to hold them in place) but not cranked down to cause the seam unintended damage. I assume the intent is for the sidestay pressure to be transferred from the stay to the stemplate and then by way of the screws and nuts, "through the deck" to the curved tube which spreads the pressure over a wider area of the hull lip so there really would be no need to torque down the mounting screws (thereby avoiding cracking the seam).
Just guessing about all of this, but I can't see what you could have done differently, unless there is a way (from inside the cuddy) to insert a support spacer between the deck/hull seam, but that has it's own challanges.
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Postby GreenLake » Mon Nov 28, 2011 5:07 pm

If you can see the hull-deck joint, what would prevent you from adding a bit of reinforcing laminate?
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Postby jdoorly » Mon Nov 28, 2011 8:09 pm

Scott, nice ESP, I can't say it any better. Yes the secret is not to tighten the nuts too much, but then I never met a nut I didn't overtorque!

I could probably squish some thickened epoxy in there come spring...
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Crack in hull/deck joint

Postby hectoretc » Wed Nov 30, 2011 9:46 pm

Moving back to the crack in my deck/hull seam... I brought my handy iPhone and got some pix this afternoon (which is becoming tonight earlier and earlier every day).

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The first picture is the bow deck, showing a repair performed across the whole deck corner by somebody before I got the boat. When it was outside in the sun I had seen the repairs on the forward portion but didn't realize until I looked at it inside under diffused angled light the the whole corner of the deck must've cracked off and been reattached at some point. That sort of explains why the forward cuddy bulkhead was loose from the deck (previous post).

Second picture shows the crack comes down to the Deck/Hull edge (note the anchor fairlead on the right and the small crack lower center on the edge of the deck.

Third picture from under the deck lip, note the anchor fairlead for reference and the crack seen in pix #2 is just barely out of frame to the left.

So this edge crack (deck to hull) is obviously a remnant of a previous major deck failure. Given this information, any suggestions on if/how I need to fix this crack? Any input is appreciated.
DS #6127 - Breakin' Wind - From the land of 10,000 lakes, which spend 80% of the year frozen it seems...
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Careful what you look for... you might find it...

Postby hectoretc » Wed Nov 30, 2011 10:50 pm

Alan wrote:I noticed in your mast sleeve photo on the other thread that there's an inspection port hole in your forward bulkhead. I'm curious about what you found in there. Do you have the L-bracket and goop that other people have found?


Alan - as previously mentioned, I also put a 8" inspection plate into the forward airspace? (not sure what to call it). I found some interesting things, and some scary things.

(at some point I fully expect to be cut off from adding additional pictures, but until they do, I'll keep piling them on.)
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First picture shows the 8" port in the bow deck. Had to go in the port side because of the damage and repair to the starboard deck. You can see the forward cuddy bulkhead inside the port right on the aft edge of the port.

Second picture, looking down through the port. All the icky styrofoam and bees nests cleaned out. looking down, the keel is that whiter part of the picture, the inside forward cuddy bulkhead is to the right. You can see here that the forward airspace actually goes under the front of the cuddy floor.

Third picture - this one is kinda kitty-whompas because I had to hold my hand down so far to get the camera around the corner and... lo and behold, there is yet more icky styrofoam stuck under there. I'll have to come up with an articulated hook to grab it somehow. The keel is on the left, with another of those fiberglass toilet paper tube stiffener things. This one looks like it has some flanges, might be part of the drain system, hard to tell.
So that's the tour under the cuddy floor from the front (where no man has gone before) Even roger doesn't have "these" pictures...

Turning the camera around and pointing it forward (and up)
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keeping in mind, all of these pictures are upside down...
First picture - on the left you can see the bottom of the repair "brace" used to shore up the fiberglass when they glued the front of the boat back on. Upper center right on the edge of the frame is the inside of the hole I repaired from the outside by stuffing a bunch of resin saturated fiberglass strands through the hole, building it up towards the outside. Pretty sure thats how the bees got in to build their nests... If only I'd have cut this hole before I started that repair... Center top is the "stemhead flange?" (is that what that's called or a Tang?) In any case, the first thing you may or may not notice is that the screws from the steamhead "just barely" are into the tang. The back one is actually through the edge of the tang. Another 1/8" and it would have missed entirely.
Second picture is a much closer shot of the stemhead screws almost not being in the tang at all. Also visible from this angle is the shadow between the tang and the deck showing the gap between but we've learned this week, all that means is you "don't crank it down hard" or you'll break your fiberglass which is what I expect is happening in the last picture.

Even to me, not having sailed a foot in this boat yet, I think it is a miracle that the stemhead has held on for... 38 years? Amazing...

Would the recommendation be to simply move it 1/2" to the (it's upside down... so that would be) right? or... is it important that it's centered and so I should find some way to add strength in another way?

and lastly... as long as I'm in here doing these things, has there been any broad consensus that it's smart to drill a hole through the upper bow and put a bolt in to hold the tang from pulling up and out?

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This is not my boat and I definitely don't want it to be... I should add that the very visible vertical piece here, which I first thought was a piece of wood to hold the deck up for the picture is in fact the vertical portion of the L shaped Tang intended as a attachment base for the stemhead. This is the part that people talk about drilling and screwing into from the bow to add shear strength since it is only held in place by some form of bonding compound.

Thanks for your inputs... Scott
Last edited by hectoretc on Thu Dec 01, 2011 3:16 pm, edited 3 times in total.
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