Thru bolt hull to top - advice wanted

abl1111 · #1 01-31-2006, 01:05 AM

A project I want to tackle this season is to remove the rub rail, and remove all the (31) year old SS screws holding the hull and top together and replace with ss bolts.

Anybody done this ?

If so, any advice or ideas ? Did you re-seal this joint too ? I want to do this once and do it right.

Thx

Trayder · #2 01-31-2006, 01:22 AM

There was recently an episode of shipshape tv where the "G"-man did this. He used "plexus" methacrylate (bad spelling) between the hull an the deck cap and then thru bolted them together. The Plexus was supposed to provide a strong flexible bond.

I hope HERMCO will chime in on this because I know he has first hand experience with PLEXUS and I do not think it was a good one.

On my 20 I glassed the new deck cap to the hull from the inside. This was how my Contender 25 was set up and it essentailly turned a 3 piece boat into one by glassing the hull/innerliner/ and deck cap together. I then used stainless self tapers to afix the rub rail, sealed with 5200.

I am sure there are better ways as well

hermco · #3 01-31-2006, 08:27 AM

ITW Plexus makes over 20 different products you can check out on their website ITW Plwxus
I got some samples and did my own unscientific tests with them and was not impressed. I would remove all old tapping screws,clean,caulk with 3M 5200,and then if you like thru bolt where possible,and as Trayder did glass the two parts together on the inside where access makes it possible. Because the 20' is a one piece cap/liner I am glassing mine on the inside at the areas I can reach,the anchor locker and rod storage etc... [img]/images/graemlins/grin.gif[/img]

stoney · #4 01-31-2006, 08:39 AM

I am curious about why you want to glass the cap to the hull. Is there signs of the deck cap being loose?
I just recored the deck cap last year my 1971 23 SF. The boat had been used and abused for 34 years and the screw together method showed no sign of loosening up. It made it very easy to remove the deck cap. If you ever have to take the deck cap off again it would be brutal if it is glassed on. The deck cap has to come off to redo the transom and we seem to like to do that job. I used the installation procedure that came with the Taco rub rail and the only problem is with screws pulling through the rail. Might be the particular rub rail I bought. Back up the screws with #8 SS flat washers so they can't pull through the rubrail. The rub rail job is a 3 man project. Good luck

TUGBOAT · #5 01-31-2006, 02:42 PM

I removed the top cap,re-glassed the inner gunnel(hull) all the way around.Cleaned all the outside & inside top caps screw holes. I re-placed the top cap(Make Sure its aligned/even) pre-drilled new screw holes every 12-14"s or so.Screwed them togther then between them I thru bolted with longer bolts. This gave Me a place to put the Tie wraps w/ holes in them for the wires.I used 4200 on the in/bottom gap then put the rub rail back on. Sealed under it w/ Quick drying 4200/5200(No Drip)?I can still remove for any reason w/a lil' more work. It's solid now.What a differenc in quietness too!
Scream'n reels'
Tug [img]/images/graemlins/cool.gif[/img]

Ikan Besar · #6 01-31-2006, 04:38 PM

My cap wasn't glassed to the hull but after reading Trayder's process, I kind of wish it had been. I no longer have an inner liner so there is no reason to ever need to take the cap off. -And therefore no reason NOT to glass the cap down.

abl1111 · #7 02-01-2006, 05:46 PM

Ok. I forgot who I was dealing with here ---> The authors of, "How to build a boat like a 'brick sh_t house' ".

If I wanted to glass the the insides together - would I actually be able to glass all (3) parts together ? I am trying to get a visual of what this joint looks like ( my boat is under wraps now ).

If I wanted, and I'm not sure that I do, I could glass the seam of the (3) hull parts ? I think it is 90% accessable. With what materials would you do this; epoxy or poly ? How many layers of what and how wide would the strips of glass be ?

Lastly, I do not know that I want to get this crazy, although I do see the merits of it.

I might just want to go with pulling the old screws, replacing with new ones and bolting in between as someone mentioned. What would I seal the screw holes with ? I like "LIFE Caulk" is this a good application for the long haul ? I have leaned away from 5200 and am not familiar with 4200, although I know what it is.

hermco · #8 02-01-2006, 06:35 PM

Quote:

Ok. I forgot who I was dealing with here ---> The authors of, "How to build a boat like a 'brick sh_t house' ".

I am not an author but I will offer an opinion based on my 25 years experience in the boat building industry. The standard method of affixing the cap to a hull and the installation of a rubrail differs with the manufacturer. In general it involves the application of a bead of 3M 5200 adhesive sealant between the cap and hull and securing the two parts with either #10 S.S. tapping screws or # 10 machine screws with washers and locknuts on the inside. Then a bead of 3M 5200 adhesive sealant is applied to any gap between the two parts prior to installation of the rubrail to prevent water from intruding into the boat. A bead of 3M 5200 is run at the approximate center of the estimated mounting area the rubrail and the rail is secured with #10 S. S. tapping screws. Then install the insert. A clean up of the excess 5200 is advised then a bead of sealant of choice should be used at the underside of the rail if any gaps are present. You now have a boat with a rubrail. However many manufacturers (Contender)and as we know "Trayder" go the extra step and "tab"/glass the boat on the inside for added strength and durability. In my experience the 5200 method with tapping screws is the standard. While rebuilding my personal 20" Seacraf I am going to go the extra mile and glass/tab where I can. I prepare the areas I will be installing the tabs by grinding then wiping with clean acetone. I cut approx 8"x8" square pieces of 1708 biax and wet out with resin on a piece of cardboard. Then I brush resin on the prepped areas and apply two biax piled on top of each other by hand using the brush to remove air bubbles.
And that is how I would build my boat like a brick sh** house! [img]/images/graemlins/wink.gif[/img]

warthog5 · #9 02-01-2006, 08:08 PM

It's my contention that all manufacture's or designer's would like to see the boat become 1 piece.

This is not the case as it's just not easy to do and costly in production work.

I did it the hard way, but it's a brick house. I did it all the way around the boat from the outside. There is a lot of fairing to get it right again. 1808 and a layer of 3/4oz mat was vacuum bagged. I filled the gap with 5200 first, let it setup for over a week and then removed the pop rivit's. Then did the glass work.

This is just one section being done.

As to removing the screw's and replacing with machine screw's. I didn't see this brought out anywhere, but I would just R&R a few at a time so the cap doesn't shift.

abl1111 · #10 02-02-2006, 12:21 AM

Thanks guys. I now have a clearer picture of what I will do. It's a little bit of what each have said - w/ Hermco leading the way !

One question: is it really a concern of the hull-cap joint shifting if I pull all the screws out at once ? Pulling all the screws out at once makes the grinding and glassing that much easier - I can do it all at once w/ nothing in the way.

What sealant is in the joint now ? ( manufact in 1975 ) Should I pull this sealant out anyway and replace with the newer 5200 ?

FYI: I have no leaks in the hull joint at all. I just feel that the SS screw need to get replaced, they have been bleeding rust on the inside liner - and I want to R/R them and add SS bolts... Glassing is a possibility, but 1st I need to see how EZ it will be to get a grinder in that tight spot...