hull to deck joint separation

For issues common to different models of DaySailer.
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Postby Alan » Wed Nov 30, 2011 11:09 pm

Yipes! I've been holding off on putting an inspection port in the forward bulkhead, mostly for lack of time. That'll definitely be on the list before we hit the water next time.

Hopefully I won't find any of the local yellowjackets - they seem to favor small gaps in the boat's cover.
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Postby Alan » Wed Nov 30, 2011 11:26 pm

"has there been any broad concensus that it's smart to drill a hole throught he upper bow and put a bolt in to hold the tang from pulling up and out?"

Talbot put a couple of no. 10 bolts through his, as I recall. Makes loads of sense to me. I'm really not sure that anything holds the vertical part of the tang in place, as least as it came from the factory.
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Postby GreenLake » Thu Dec 01, 2011 1:25 am

"transom" = the flat panel at the end of the boat. You mean "bulkhead" or something else, but you shouldn't be able to view the transom from the front port.

Gelcoat crazing on the deck:

This is due to flexing. Could be that the gap to the stemhead bracket allows the stemhead fixing and with it the deck to move a bit, or someone overtightened the bolts at one point, bending the deck.

Could be that the laminate has weakened a bit. I would find a flat workbench, put down a piece of wax paper and build up some laminate to the thickness of the gap, with a narrow top (where it will rest on the bracket) and a wider bottom, where you'll glue it to the deck.

Cut/sand it to fit, remove the bolts, drill some holes into the piece and glue it in place between deck and bracket. Reinsert the bolts and then you can tighten them to your heart's content. (I wouldn't bother with moving the bracket or re-drilling it - the bolts would have pulled out in 36 years...so consider this has stood the test of time).

That will strengthen and immobilize the deck. Then you can gouge out the cracks (turn them into wider/shallower V-shaped grooves) and fill them with gelcoat repair past, of filler (depending on whether you plan to keep the gelcoat or paint over it).

I second the notion of securing the vertical part of the stemhead bracket by drilling (from the front?) and inserting some bolts. You wouldn't need to tap the bracket, gluing the bolts in place would be fine - they would act on shear.
~ green ~ lake ~ ~
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Postby hectoretc » Thu Dec 01, 2011 9:38 am

GreenLake wrote:"transom" = the flat panel at the end of the boat. You mean "bulkhead" or something else, but you shouldn't be able to view the transom from the front port.


Thanks GL - I meant "keel" in that paragraph and have gone back and corrected the post.

Thanks also for the inputs on the stemhead spacing and my concerns about the attachment to the L tang bracket. I guess I agree with you that if it has held for almost 40 years, theres no reason to think it won't hold for another 5 or 10, except that this boat has clearly suffered substantial trauma in the past few years. I have no way of knowing if that changes the dynamics for the stemhead or not, I guess if the bracket hasn't moved it shouldn't change the operating conditions. My personal experience has been that mechanical things don't get better with age, or even generally stay the same.
I like your idea about building a shim to go in the airspace between the deck and the L tang. To ease my other concern (justified or not), I can make it wider and imbed a large fender washer into the fiberglass centered on where the aft screw will go, and once the aft stemhead screw is reinserted, add an additional washer and nut on the bottom providing a backup surface to hold should the screw ever decide to slip sideways out of the taped tang hole.
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 ChrisB » Thu Dec 01, 2011 11:15 am

Yipes is right! That is scary These pics have definitely moved the priority of this task up on my list.

I can't tell from the pic how clean the underside of the deck is but you might wipe it down with a mild bleach/water solution to kill any mildew on the underside of the deck. This will allow the laminate suggested by GL to better adhere to the underside of the deck. Once it is reassembled, you could add washers and nuts to the bolts under the tapped bracket to give and extra measure of confidence the tapped holes in the bracket won't fail.
Chris B.
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Postby Moose » Thu Dec 01, 2011 2:14 pm

I have a DS3 that got in to some rocks before I got it, the gunwale where the deck and hull meet is a little too flexible for my liking from the chain plates to the stem. The possibility of deck separation (I havent sailed this boat yet) really scares me.

Short of separating this area and re-bonding it as shown on the previous page I was thinking of making a piece of hard wood that would fit under this lip that I could bond in with some thickened epoxy. Then through bolt every few feet for good measure. This should really increase the cross sectional area of the gunwale and stiffen it up.

I would hate to have to tear the boat apart, I'd almost rather look for a new hull.

Any thoughts or suggestions?


x-section of reinforcement

1154


x-section of through bolt

1155
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Postby hectoretc » Thu Dec 01, 2011 3:10 pm

Hi Moose - This is an area that I am completely unqualified to offer suggestions (which is why I'm asking so many questions). But I can suggest you read the words of others who do know a lot more about it than me. Before you do the bolts through the deck thing, be sure you read jdoorly's warning about deck seams in this same thread on page 1 (about the 8th or 9th post from the begining).

I won't even try to paraphrase here, just be sure you read it before decide to bolt the hull/deck together.

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 ChrisB » Thu Dec 01, 2011 3:26 pm

The only issue I could forsee would be trapping water next to the wood and setting up dry rot. Assuming you adequately sealed the wood or the joint between the wood and FG, I don't see any reason why this would not work. Either this approach or using wood or SST tubing (discussed elsewhere on the forum) would require paying close attention to not overtightening the through bolts to the point that the epoxy joint between the hull and deck is cracked or damaged.
Chris B.
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Postby jdoorly » Thu Dec 01, 2011 4:06 pm

Moose, here's the gunnel profile I found in the vicinity of the chainstays...
1156
And when I tightened some 1/4-20 bolts (in the position you show) the result was similar to hectoretc's 5th pic on this thread. Your boat may be different but if you climb inside the cuddy you may be able to see your hull-deck joint or you may be able to measure and plot the curves.
DS2 #6408 "Desperado"
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Postby Moose » Thu Dec 01, 2011 4:33 pm

I see what you are saying about the stress fractures. Likely due to brittle fiber glass and the gap between the hull and deck or over tourqing. This might be avoided with a large washer on the deck side and a thick (hard) rubber washer on the bottom to allow flex.

The daysailer 3 profile seems to be much squarer than the 2 that I previously had. I think I read this was an attempt at better bonding the two. Specifically to address this problem. The square profile seems to not have the gap, but I will have to check.

I think I might be able to get away without through bolting if I make a robust enough repair.

Does anyone think it will work? just looking for opinions, not putting liability on anyone.

my other thought is to remove the current chain plates and replace them with ones like the early daysailers had. Basically a long tang through bolted into the hull. (of course with a backer added inside the cuddy to prevent tear-out)
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Postby GreenLake » Thu Dec 01, 2011 4:55 pm

@Moose: Before you insert the wood, coat all (!!) sides with unthickened epoxy to seal. After mounting, give the underside and exposed front/back another coat (could use thickened epoxy as well, for the second coat).

Then make sure that you coat the insides of all thru holes, and finally, after curing, paint over the wood to protect it from UV.

With that, you'll substantially reduce any chance for rot.
~ green ~ lake ~ ~
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Postby Moose » Thu Dec 01, 2011 5:22 pm

@GreenLake: I plan on doing this! thanks for the advice!
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Postby hectoretc » Thu Dec 01, 2011 6:26 pm

GreenLake wrote:@Moose: Before you insert the wood, coat all (!!) sides with unthickened epoxy to seal. After mounting, give the underside and exposed front/back another coat (could use thickened epoxy as well, for the second coat).


Another new set of terms for me, what (please) is un-thickened epoxy vs. thickened epoxy?
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Postby GreenLake » Thu Dec 01, 2011 6:51 pm

For lamination you want your epoxy to flow so it wets out the glass. For glueing, you want something that (like the ketchup) "doesn't run". (Or you get an unholy mess...).

Traditionally, you'd buy the thin epoxy and would mix a thickener into it if you wanted to use it as a glue (or wherever you wanted something other than a thin coat).

Some manufacturers offer these things in separate packages. I'm a happy user of the System Three series. For glueing they sell "GelMagic", which I buy in the caulk-gun compatible cartridge with self-mixing tip. (West system sells something similar as 6-10).

Really my favorite epoxy glue and the mixing tip makes it really easy to get the glue just were I want to and not have to worry about mixing too much. (As long as none of the mixed epoxy sits more than a few minutes "in transit" in the tip, you can keep working and when you're done, the waste amounts to the contents of a single tip - you can use another tip with the same cartridge on another day.)

For lamination, I use their SilverTip laminating epoxy. Very nice, blush free. Great for coating bare wood, but you could also get some formulations that are even more "liquid", such as their "Clear Coat" or their "End Rot" products (the latter is like water and is intended to soak into wood, for protection).

Most versatile for work on the DS is just to have one glue cartridge and one set of laminating epoxy. Unmixed, the stuff keeps for many years, so you can get a quart and keep it around for future use.
~ green ~ lake ~ ~
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Postby Skippa » Sat Dec 03, 2011 9:56 am

GreenLake,
Would like to take this opportunity to tap into your considerable experience with epoxy.
In my digging and floatation removal project, I also found that the "L" bracket had seperated from the goop in the bow. (1980 DSII). This will be one of the first spring projects as the boat is now in hibernation.
My thought is as follows.
Use modeling clay (play-doh) to get the shape of the bow and the thickness needed so I can make a mold also out of modeling clay and pour a thickend epoxy in the mold. This would give me a custom fit spacer to replace the goop.
Drilling in from the exterior at the bow, two holes through the epoxy spacer and verticle section of the bracket to recieve #10 nuts,bolts and washers.
My original thought was a wood spacer between the bow and the tang to replace the goop.
Your thoughts on using a mold and epoxy? I believe it would be about an inch to an inch and a half at it's thickest point.
Thank you.
Kevin
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