1974 170 rebuild

[mshugg]

Mshugg, when you laid all that 1708 in there how do you make sure the hull shape stayed the same?



I just laid the second piece of 3/4 coosa in transom(picture below), went a lot smoother than the first time that's for sure. Tomorrow or sunday after i lay a couple sheets of glass on transom i will be filling in the stringers with foam and getting ready to glass the entire inside of the hull.

My main concern and question i have with this step is should i be worrying about my hull shape being close to perfect to the cap?  I didn't put braces supporting the beam. If i lay 1708 without the cap on, will it be a struggle to get the cap back on? Should i take measurements and make braces before i do it? The braces are just a PIA to constantly walk over or under. 
-----I guess i should mention i have the boat supported with boat jacks on the two aft corners and a 2x6 brace about 4' long on each side of hull underneath the stringers(aft near where the stringers delamed and was flexing under weight) two jacks underneath where the step up would be and a stack of blocks under the forward most part of the keel.(I'll just post a picture below..


Second piece of 3/4 coosa to the transom





I drew in blue where the supports are, This is an older picture before i added them.

I did take steps to block my hull in place prior to removing any major structure.  My liner, sole transom and stringers stayed in place until I had boat stands under the transom at the chines, boat stands forward, and my keel was supported in 3 places.   My transom was rebuilt and my stringers tied in before I added the reenforcement along the hull/deck seam.  I also took measurements at 4 points  to be certain the beam stayed the same.

With that said, the reenforcement didn’t completely stiffen the upper hull sides.  They remained flexible until I added other hull stiffeners, so I wouldn’t worry too much about adding 1/4” or so of glass strips for screwing. Another option, that some higher end builders use, would be to glass strips of aluminum into the hull to receive the screws.  I chose not to do aluminum, because of corrosion potential, but it would work too.   Just glassing in strips of 1/4” plywood works too.  The original wood lasted a long time.  You definitely have options.

[Corynelsonflkeys]

That area you have your hand on looks really thick - is the hull that thick there and below that spot?

No it’s not that thick, I was pulling it down to show that it was rotten and peeling off. With both inside and out of my hull sanded I can see right through it. I’ll probably add 2 or 3 sheets of cloth around the entire inside. Think that should be enough?

[RickK]

Ahhh, perfectly clear after you point that out 
Yeah, I'd cut that inner floppy part out and Michael has a good idea in using laminated strips of glass.  As long as you don't modify the outer hull sides, the cap should fit.  usually when you pull the cap off you run pieces of wood across the top of the hull to keep the shape. then you stiffen/ lock the shape in by adding layers of cloth. If you look at the underside of the cap there is about 1 1/2" of room for the shoebox to fit over the hullsides.
As for # of layers of cloth on the hull I did one when the hull was completely gutted, and I was using epoxy.  Looks like you're using poly, correct? If so, maybe 2 on the hullsides and do it wet on wet and run from top of hullside through chine and to the stringer.

[Marcel4t]

Also if you are concerned about screws holding, you can use nylon lock nut's and bolts...little more work, but solid.  My FB's cap is both screwed and bolted down. 

[Corynelsonflkeys]

I think I will be going with Michaels idea of laming up a bunch of strips but I wasn’t exactly concerned with the integrity of the bolts, I was pondering  more towards supporting the actual cap itself (since it won’t be connected to the floor anymore. But I guess once I restore the cap and lay a bit more glass in it and add a few supports It’ll be stiff. I was actually thinking about just glassing the cap on rather than screwing. Everything with be composite so I have no plan of every taking it off and I will be glassing in two boxes in the rear corners.

[mshugg]

If you’re glassing the cap on, you won’t need to build up much thickness at all since there’s no need for screw retention.

[Corynelsonflkeys]

Quick little update..


Had a day to spare on monday and started pouring my stringers and put two sheets of 1708 on them.
I finished forming the stringers at about 3pm i ended up using 4 gallons total(A+B)

Placed the 2 sheets of cloth and marked them. Started from the outside-in and it went pretty smooth, didn't brush resin on the inside of the stringer until everything else was already wet so i didn't make much of a mess but i used a full 5 gal bucket of resin. I would have kept adding more cloth but i had no resin left... and it was 3:30am. they're not perfect by any means but tomorrow i'll sand them down and fix any air pockets, i also plan to raise the deck a couple inches since i'll be putting a bigger engine so i'm trying to figure out how to go about that. I should have just poured more foam higher but i figured i could just ad something after i got a couple sheets to get the stringer reattached to the hull. Lessons learned. I also ran out of pour foam.

Here's a couple pictures

[Marcel4t]

Nice!  How did you extend your stringers back to your transom?  And for raising the floor, someone on here raised theirs by cutting 4x4 white PVC fence post in half, putting them on top of stringers, and glassing them down.  Seems like a good route I may take.

[Corynelsonflkeys]

I took a 4x8 sheet of.... the stuff you wrap cabinets in..super thin and shiny on one side..and cut it to match the stringersides, braced it with pieces of 1x1 and 2x4 and then poured foam, pulled the boards off and shaped them with a sawzaw and hit em with a sander to smooth the edges. It worked great and I would highly recommend it! To add the extra 2inches I think I’ll just grab an extra pour foam and do the same thing, the more float the better for me. I’ll also be foaming in the gap between the stringers and the outer walls anyway.

[RickK]

Formica?

[Corynelsonflkeys]

Yes! Formica with white on the outer side. It was like $10 for a 4x8 sheet. It stuck a little bit but pulled off easy enough.

[Corynelsonflkeys]

Sanded down everything yet again and prepped for more 1708 tomorrow. Also got the center stringer completely removed and sanded down. Made a new one out of coosa. I only used 1 piece of coosa but i think tomorrow i'll cut another matching piece and double it up. I cut and laid all the 1708 for the hull walls as well. Also cut and fit a bulkhead but don't plan to put it in until i raise the stringers.

[RickK]

Looks good - that'll help stiffen it up.  Are you going to lay in glass on the hull bottom on the outside of the stringers?
Did you get the cloth wet out soon after? Don't leave the glass exposed for long periods (days) or it'll absorb moisture.

[Corynelsonflkeys]

Looks good - that'll help stiffen it up.  Are you going to lay in glass on the hull bottom on the outside of the stringers?
Did you get the cloth wet out soon after? Don't leave the glass exposed for long periods (days) or it'll absorb moisture.

When I laid up the stringers the cloth went to the walls and in some spots a few inches up the walls(see previous pictures) and about 6'' below the stringer as well so the cloth you see in the pictures is all overlapping a couple-few inches. I put the cloth out yesterday and was meant to do it today but had a propane tank blow up in my face last night(all is well just a few flash burns) but i put a tarp over the entire boat and it's pretty windy so the humidity isn't too terrible at the moment. Do you think the tarp will be enough? I also have my entire roll on a rack similar to the one you built but i keep it covered in cardboard and plastice. I haven't had a problem yet but if it is not advised i will move it. **Remember, all of this is under my house which is completely covered in trees and can not get wet

[RickK]

Ahhh, I see the other pics where you lam'd up the stringers. Sorry for the confusion.
Sounds like you protected the raw cloth - I would expedite wetting it out though. I remember cutting some glass one day and it looked like rain and knew I didn't have time to wet it out, so I removed it, rolled it up and took it into the shop 'til the next day.