Resealing the hull to deck joint

b_arrington

b_arrington

Well-Known Member
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Feb 21, 2007
3,481
Setauket, NY
Boat Info
Back Cove 37
AB Ventus 9VL
Engines
Cummins QSC 8.3 600
I need to undertake this project and could use some advice especially with sealant selection.

Last season I had to stick my head into the space the starboard hull side and the interior. I noticed it was quite bright in the area behind the head - too bright. The light was coming in from a fairly large gap in the hull to deck joint and the rub rail. I put this repair on my spring list, and spring is here.

So far I've removed the rub rail all the way around the boat. Boy, it is DIRTY. I found that MANY of the screws holding the hull and deck together were loose and started to back out, especially in the forward area. Luckily they all seem to snug right with with an electric driver. The sealant has clearly failed in some areas of the joint as well.

So now I'm left with cleaning up the joint and applying proper sealant. I definitely want to do this right to avoid leaking.

Here's my plan:
  • Clean the old sealant out of the joint. I have an oscillating tool with a blade that is excellent for this.
  • Partly back out the screws to loosen the joint, to allow a space for sealant. Force sealant into the joint.
  • Remove and reinsert the screws 1 by 1, and put some sealant in the screw hole.
  • Run a bead of sealant along the bottom edge of the shoebox joint.
  • Clean and reattach the rub rail, adding some sealant to each screw hole that penetrates the fiberglass.

Does this sound about right? Any thoughts from experience are certainly welcome.

I'm struggling a bit with what type sealant to use. I did read one CSR member's experience on the same repair, and he recommended a non-adhesive sealant. But after reading multiple "guides" on sealant I went away with my head spinning.
 
Sounds like you're on the right path, and definitely don't envy the chore you have at hand. I would think you would want to use the best sealant as possible, so 5200. Wait for others to chime in, but would be my thoughts on this.
 
I wouldn't use 5200 personally. When I redid mine, I used life caulk, but 4200 would work too. My issue with 5200 is that it is impossible to remove if needed, and that hull joint needs to have some flex, I don't know that the 5200 would flex much before it starts tearing apart the gel coat.
 
If this is the joint that mates the upper deck to the hull then it is a structural joint and requires adhesive. During assembly they pookey that joint with the adhesive and the screws are there to pull the deck and hull together until the adhesive cures. Much of the boat's structural hoop strength relies on that joint and it's adhesive. 5200 would be my choice which many boat builders now use however I would seek council from Sea Ray customer service. Take a look at this link also:
http://solutions.3m.com/wps/portal/...pair/GeneralBoatRepairs/SealantAdhesiveGuide/
 
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ttmott said:
If this is the joint that mates the upper deck to the hull then it is a structural joint and requires adhesive. During assembly they pookey that joint with the adhesive and the screws are there to pull the deck and hull together until the adhesive cures. Much of the boat's structural hoop strength relies on that joint and it's adhesive. 5200 would be my choice which many boat builders now use however I would seek council from Sea Ray customer service. Take a look at this link also:
http://solutions.3m.com/wps/portal/...pair/GeneralBoatRepairs/SealantAdhesiveGuide/
Click to expand...


+1 on the structural. After all, screws don't flex.
I have seen them use a 2 part adhesive that uses a special caulking gun and it mixes in the tip. But I would call Sea Ray.
 
Link to my adventure...
https://r.tapatalk.com/shareLink?ur...&share_tid=80914&share_fid=10569&share_type=t

Rub rail separation




You're on track. You'll have to take out more than one screw at a time to get enough room between hull and deck. I used plastic trim removal tools to space them out even more so I could get a good amount of sealant up there. Sea Ray told me to use Life Caulk so I did. Have plenty of extra SS screws on hand to replace the ones that break off. Remember to pilot drill with small drill through both, the follow up with clearance drill for deck only.

Sent from my SM-G930V using Tapatalk
 
I have to do the same job on mine. Did you need to replace any of the screws that hold the deck to the hull, or the rub rail to the hull? I assume that these are 2 different lengths? Do you happen to remember how long they were?
I am hoping that to avoid 10 trips to the HW store in the middle of the job. One last question. Did you need to replace any of the screws with larger diameter ones because the holes were stripped? How many tubes of caulk do I need?

I also need to replace one section of the rub rail. Both the stainless steel part and the white part. I think that these are Taco products, but their catalog is huge. Does anyone know the correct part numbers?
 
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importmonkey said:
Link to my adventure...
https://r.tapatalk.com/shareLink?ur...&share_tid=80914&share_fid=10569&share_type=t

Rub rail separation


You're on track. You'll have to take out more than one screw at a time to get enough room between hull and deck. I used plastic trim removal tools to space them out even more so I could get a good amount of sealant up there. Sea Ray told me to use Life Caulk so I did. Have plenty of extra SS screws on hand to replace the ones that break off. Remember to pilot drill with small drill through both, the follow up with clearance drill for deck only.

Sent from my SM-G930V using Tapatalk
Click to expand...

Thanks. Your pics look a lot like my situation.
I understand your point about taking out more than one screw. I mentioned that because in Jason's post he said Sea Ray advised to not remove more than 1. However in his pics the spacing between screws looks much wider than mine.

Can you confirm you used Life-Calk and not Life-Seal? I has because Life-Seal has this description:
It provides a durable permanent watertight seal for joints subject to structural movement. Use for sealing decks to hulls...
Click to expand...

My initial thought was to use something like 3M 4200 because, as others have said, it's a structural area bond. I was very surprised that according to Jason, Sea Ray advised NOT so to use a strong adhesive.
 
skibum said:
I have to do the same job on mine. Did you need to replace any of the screws that hold the deck to the hull, or the rub rail to the hull? I assume that these are 2 different lengths? Do you happen to remember how long they were?
I am hoping that to avoid 10 trips to the HW store in the middle of the job. One last question. Did you need to replace any of the screws with larger diameter ones because the holes were stripped? How many tubes of caulk do I need?

I also need to replace one section of the rub rail. Both the stainless steel part and the white part. I think that these are Taco products, but their catalog is huge. Does anyone know the correct part numbers?
Click to expand...

I only just started, so can't answer everything yet.
  • Hull / deck screws. Have not had to replace them. I don't see a need so far. They are stainless and covered by the rub rail so are in good condition.
  • Rub rail screws. All came out easily. No need to replace any so far.
  • Stainless insert screws. May have to replace one because I stripped the head. It was gunked up with wax and the screwdriver didn't seat well. .
  • Screw length. The screws for the stainless insert, plastic rail, and hull to deck joint are all the same length. IIRC, they looked to be about 1 inch. They only exception was 3 screws for the rail: at the back corners and the bow. Those screws were larger diameter and longer (about 1 1/4 or 1 1/2).
  • Stripped holes. Out of 150 or so screws for the rail an insert, so far perhaps 1 or 2 holes for the rail were stripped. I snugged up about 25 hull/deck screws and none were stripped.
  • Caulk: I haven't started. But I'm guessing 2 or 3 tubes. I plan to buy 3 and return if needed.
  • Rail part numbers: It's possible that different part numbers are used on different models. I would remove a section of your rail, measure the parts, and check the profile and measurements against the Taco catalog.
 
Thinking about the screw situation got me wondering. If the hull to deck screws tend to come loose, why didn't Sea Ray use something like stainless pop rivets? I'd think they install faster than screws with a pneumatic rivet tool. Rivets are pretty cheap vs. a stainless screw.

Would there be a down side to replacing all the hull to deck screws with stainless closed-end rivets (which make a water-tight seal). There's no way they would back out in the future. And it's not like I want to separate the deck from the hull.
 
I would use West 6-10 epoxy adhesive screwed together then seal the rub rail. No excuse for this crap to happen. My almost 30 year old boat doesn't have these problems and it goes out when most stay at the dock. You want it as strong and permanent as possible.
Good luck let us know how it goes.
 
I think the idea is that the main target for bumps is the rub rail and better it flex a little than crack because it's rigid.

Sent from my SM-G930V using Tapatalk
 
I think the idea is that the main target for bumps is the rub rail and better it flex a little than crack because it's rigid.

Sent from my SM-G930V using Tapatalk



I should clarify I would epoxy the hull joint. Screws hold it until it sets. After that run sealer behind the rub rail screw it on then seal the rub rail top and bottom. I could be wrong but seams best to me. Is that what your getting at?
 
After reading the description of the West Six10 product, it seems like a good product but I don't think it's right for this application. They describe it as being used for fillets, gluing, and wetting out fiberglass. Also looking at the elastic properties, it seems much more rigid and less flexible than other solutions. Being at the rub rail where there is a strong possibility of striking something (like a piling or boat), I'd be concerned about the epoxy cracking.

Two other things about it: 1) The stuff is comparatively EXPENSIVE. You only get 6.5 oz in a tube for $25. That's nearly 2x the cost of other options. 2) Epoxy is useful stuff by I try to avoid working with large amounts of it. It invariably gets where I don't want it, including on my hairy arms, and the stuff is PITA to clean up.
 
kevin27 said:
I No excuse for this crap to happen. My almost 30 year old boat doesn't have these problems and it goes out when most stay at the dock. You want it as strong and permanent as possible.
Good luck let us know how it goes.
Click to expand...

My experience with three other SRs that I owned is the hull/deck joint is under designed compared to your boat. Tiara uses a shoe box joint also, but they do not flex in heavy seas or even with some hard docking. Maybe the construction is more robust and the design tolerances a little tighter. Whatever, they don't leak. We are in our 13th season and the boat is still water tight with no musty smells.
 
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I did this last year on our 1999 330. I had a problem with water leaking into the bilge at the stern. The water would run down the rub rail, spill over and then come in between the joint.

I removed the rub rail and every screw in the joint. I found that Sea Ray basically just waved the caulk gun close to the joint and called it good. There was just a little bit of silicone every few feet. Every screw was loose.

After removing all of the screws I used plastic wedges to separate the joint; not up and down, but out and in. I then roughed the fiberglass/resin/gel coat. After this I cleaned the joint thoroughly with acetone. I used 5200 liberally in the joint moving about 10 feet at a time using the wedges. After 10 feet I would run screws in. I just kept going all the way around the boat. Where the screw holes were stripped I just ran the screws in and left them, figuring the 5200 would hold them. There were a few spots where the joint was not coming together all the way and I added screws. After the joint was together I started putting the rub rail back on and then the stainless insert.

It probably took 2 days total once I started putting in the 5200. Holy cow are there a lot of screws! Fortunately this has a long dry time so I was confident that all the screws I was putting in were getting into wet 5200.

Anyway, I feel as though the hull to deck joint should be as solid as possible. As somebody mentioned above, the screws don't flex, so why should the joint they are in flex.

Last summer I had the boat in 5-6 footers coming down Grand Traverse Bay with a strong south wind. We buried the bow about six times and nothing leaked or moved. The boat felt very solid. I have not noticed anything starting to crack since this is a solid joint now.

Theres my story. Hope it helps.
 
skibum said:
I have to do the same job on mine. Did you need to replace any of the screws that hold the deck to the hull, or the rub rail to the hull? I assume that these are 2 different lengths? Do you happen to remember how long they were?
I am hoping that to avoid 10 trips to the HW store in the middle of the job. One last question. Did you need to replace any of the screws with larger diameter ones because the holes were stripped? How many tubes of caulk do I need?
Click to expand...

Update

Screw sizes: 3 types of screws were used. All are stainless oval head sheet metal screws.
  • The VAST majority are #8 x 1 inch. Used for the hull to deck joint, rub rail, and the stainless insert.
  • Some (perhaps 10) are #10 x 1.5 inch. These were used primarily on the corners and some areas where the #8 screws apparently didn't hold.
  • #10 x 1 inch. Perhaps 5. Used only in a couple holes. Apparently for areas where the deck was popping out and the factory needed more grip to pull it in.

How many need holes were stripped? Maybe 3 so far in the hull to deck joint. I replaced the #8 screws with #10. I needed to replace maybe 2 other screws so far.

How much sealant? I did about 97% of hull to deck joint so far. I've caulked between the hull and deck both sides except 3 feet, and ran a bead at the bottom of the joint on 1 side. I've used 2 tubes do far. I think I can finish the job with 1 more. At most I will need 4 tubes for the job. I'm not planning on full disassembling the transom joint. It looks pretty good, and it would be a real PITA to get in there with the swim platform. I'll just run a bead of sealant along the bottom of the joint.
 
For anyone else that needs to fix their hull to deck joint, I did a lot of work on mine over the weekend. Here are some impressions and tips from what I've done so far.

The biggest take aways are these: 1) There's very little sealant in the hull to deck joint from the factory. 2) The job takes some time, but with the right tools really isn't so bad. If you have any decent fix it skills you can do it.

I had already removed the stainless and plastic rail. This weekend's task was to wash the joint, open it up, clean, caulk, and close it up. I got about 90% of that done.

  • First, the rub rail and the joint collect a LOT of dirt. I did a general wash first with boat soap.
  • Next I removed all the screws on each side starting from the aft corners. As I removed the screws I watched for movement to see if I needed to stop and leave some in for alignment purposes. It was not needed on the sides.
  • At the bow, I left in a few screws toward either side. I started to get a lot of upward movement and was concerned if they were all removed the entire deck would spring off and I would not be able to reconnect it. There seems to be a good amount of sealant so won't fully disassemble the bow.
  • The port side had a decent amount of caulk in the joint in some places, but not much overall. What was there had failed.
  • The starboard side had a shockingly small amount of caulk in the joint. At most, there was a small bead applied to the bottom of the joint after the screws were installed. I'm surprised I didn't have more leaks.
  • When removing the screws, in many places the deck sprung away from the hull about 3/4". In others only a slight separation occurred. The range was 1/8" to 3/4" with the average being 1/4 inch.
  • Removing the old caulk. Using a cordless oscillating tool with a scraper blade is the way to go. I ran it down the hull in one pass, then down the inside of the deck joint in a second pass.
  • Cleaning the joint. I used some M.E.K. substitute on a rag. I used MEK because it's compatible with the sealant I chose, and evaporates slower than acetone. I wrapped the rag around the blade of a 2" plastic scraper and ran that up and down the joint, changing often. There was a LOT of gunk in there comprised of old caulk and general grime.
  • Wedging. Some areas of the open joint were too small to easily get the caulk tip in. I used plastic wedges (from a laminate floor project) to open up the joint.
  • Caulking. I ran a thick bead of caulk from stern to bow under the seam. Ensured that I got a continuous bead. Also made sure to get some on the screw holes to seal up when the screws were installed. Pulled out the wedges as I got to them. Oh, and use rubber gloves. The caulk gets all over. I went through about 7 pair.
  • Installed the screws back to front again, closing up the seam. Added sealant to any screw hole where there wasn't any. An impact driver is an excellent tool for speed and to ensure you don't overdrive the screws.
  • As the joint closed some of the sealant squished out as I expected. Smoothed out the excess and ran a bead of sealant along the bottom edge of the joint to ensure it is completely watertight. Cleaned up any drips with MEK.

Next items:
  • Finish aft corners. The gap between the hull and deck here is HUGE. It was jammed full of sealant and needs to be recaulked. I ran a tube dry and didn't want to open another at the end of the day.
  • Seal the bow and stern. The joint right at the bow is pretty tight. Just going to run a bead of sealant under the joint. Same for the stern above the swim platform.
  • Clean and install the rub rail. Plan on adding some sealant to each screw hole as it penetrates the hull. Because there was so much dirt on the inside of the rail that cause black streaks I'm considering caulking the top and bottom of the rail. Not decided yet though.
  • May polish the SS inserts on my buffing wheel at home. On the fence about this one.
 
I think the current wisdom is to use caulk on the upper edge of the rubrail, but leave the bottom open. This way, when water gets in, it can also get out.
 
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