1974 170 rebuild

[RickK]

 

[Corynelsonflkeys]

Alrighty, I canceled my charter today due to wind and decided it was a boat work day. I got the core laid in, pretty sure it went well. I ended up using some of the clean fiberglass dust i had from prepping the skin for the core and a bunch of cabosil, i mixed about 3qts at once and boy was my forearm sore! Next time I will be doing a couple small batches instead. I lucked out and mixed my hardener perfect. It was just starting to kick when I was taking my gloves off. I screwed a few pieces of 2x6 to clamp it down and i had a ton ooze out. Tapped around a bit with my knuckles and it seems to have no hallows. I'll post some pictures after I get it all cleaned up. Next step is a few more sheets of cloth and the start on the stringers.

Oh and about the whole pipe idea, The water is definitely pooling about 10'' forward but i normally jack my trailer up pretty high when I'm rinsing anyway so i'm not too concerned pus where it pools i'm probably going to have a bilge pump. 

[RickK]

Alrighty, I canceled my charter today due to wind and decided it was a boat work day. I got the core laid in, pretty sure it went well. I ended up using some of the clean fiberglass dust i had from prepping the skin for the core and a bunch of cabosil, i mixed about 3qts at once and boy was my forearm sore! Next time I will be doing a couple small batches instead. I lucked out and mixed my hardener perfect. It was just starting to kick when I was taking my gloves off. I screwed a few pieces of 2x6 to clamp it down and i had a ton ooze out. Tapped around a bit with my knuckles and it seems to have no hallows. I'll post some pictures after I get it all cleaned up. Next step is a few more sheets of cloth and the start on the stringers.

Oh and about the whole pipe idea, The water is definitely pooling about 10'' forward but i normally jack my trailer up pretty high when I'm rinsing anyway so i'm not too concerned pus where it pools i'm probably going to have a bilge pump. 

Yup, that's the problem caused by all the layers of cloth and core. We had one member that actually drilled a drain through the hull bottom and used a garboard type plug on the inside to get that 1" or more of water out.

[Corynelsonflkeys]

The transom core is in, i only used 1 sheet of 3/4 coosa and i kind of wish I would have cut 2 and sandwiched first but my fiberglass shop here in the keys told me it would be plenty so I'm going to add an extra piece where the engine sits just so i have a little bit more girth there. **Learning experience** But i will add a couple more sheets of 1708 to ensure the strength. It feels rock solid right now with 4 layers of 1.5oz cloth, on the skin, fiberglass dust and silica for putty, 3/4 coosa, 1 layer of 1708. It got dark and i was pretty spent so i called it a night. I then decided before i put too many more layers of glass on i want to tie the stringers back in to ensure strength is transferred into them.

So to the questions.
As you see i have about 2 feet of stringer completely removed. How should i recreate the stringer? Should i just refill the existing stringer with foam and pour out two block and shave them to match and then wrap them in cloth? Or should i buy a sheet of ply and make a mold for the glass?

Before i go any further into this does anyone  have strong feelings about only using 3/4'' coosa and 1 1/4'' section where the engine sits? Am i going to regret this later? Engine is still to be determined put either a 2 stroke 130 yamaha for the right price (if anyone has one??) or a 2018 140 suzuki. So we're looking at anywhere from 300-400 lbs back there, I just found a 47 gal fuel tank which is 10 more than what i have now so i might get a little more weight from that if i end up getting it. Otherwise I'll do some battery shifting. I plan on making this boat capable of doing flat bahama and tortuga runs,  with a couple friends so that's the purpose of a larger tank.

Also ill be filling in the side cavities with foam before laying the deck down since i'll be doing a completely flat deck they will be water tight .







I also finally removed the step and cap!

[RickK]

Don't rely on 1 sheet of anything unless it's 1.5" thick.  You don't want anything nasty to happen, especially after you hang a high $ engine on it. I understand Coosa is expensive and if you can't afford another, either wait until you can budget it in or get some marine 3/4 plywood ($80/sheet) and laminate that on top of the whole width, not just where the engine will be.  The transom needs to tie into the hull bottom and sides and all become one so when the engine pushes on the "boat" as it moves through the water everything is strong enough to take the power.

[Marcel4t]

For the amount of effort and money you are going to put into this boat, going with another 3/4" of something is worth it, even just for piece of mind. One day you'll see a small spider crack on transom and it'll freak you out because your not confident now.  You probably have plenty of other work to do while you wait on a piece of Coosa to be delivered, so order a sheet (or go with marine ply like Rick said).
What I plan on doing to tie my stringers back in is to use cardboard to make "molds" in the shape I want for the stringers, poor some foam, them carve it to size and glass.
Good luck!

[mshugg]

You definitely want to add another sheet of core.  Coosa reccomnds that you match the lhickness of the original core.  Another sheet of 1/2” Coosa would get you there, but 3/4” is significantly stronger without adding much more weight and cost. 

As for your stringers, the easiest option would be to clean out and tab in the sections that you removed.  Then, use a hole saw to drill an access to pour in 2-part foam.  Four pound density would be a good replacement for what was there.

[Corynelsonflkeys]

That's why i love you guys! I was doubting my glass shops faith in one layer of 3/4 coosa, i got a pretty good deal i think i paid like 220 for it so i don't  mind grabbing another one. I'll be chartering this boat so it needs to be done right and i'm way under budget thus far so a 1 sheet of coosa isn't going to kill me. So i will buff out the the existing piece i put in and sandwhich another piece. More practice for the next project anyway!
Mercel, i think that's what i'm going to do as well for the stringers i assume that'll be the easiest way to go about it.

[RickK]

Ended up getting a full roll of 1708(150lbs), 5 1/2'' 4x8 sheets of foam, 4x8 sheet of 3/4'' Coosa and a few buckets of poly resin.

So you found out that a 4x8 sheet isn't enough to do 2 layers (I did too but with marine plywood), so I can see why you wanted to try one layer.
The poly thing, ... You need to make sure you use 3/4 or 1.5oz CSM with the 1708 because CSM melts (the binders do) with/into the poly but the 1708 doesn't (1708 has a 3/4oz layer of csm sewn in on one side). Being that the 1708 has a layer of CSM  on one side you need to scuff into the shiny side (the side that doesn't have the "scrim" attached - I think I saw that on your rebuild pics) of the 1708 enough to allow the CSM on the next layer to bind to the poly on the previous layer.
Here is a pic of my 2 layers of marine plywood with 3/4oz+1708+3/4oz between them - I used poly also in this portion.

[Corynelsonflkeys]

Haven't picked up the new sheet of coosa yet so i had a day off and decided i'd get working on some other stuff for now.

I spent the past two evenings sanding the entire inside of the hull and deciding what parts of the stringers will stay and what will go.

Since i started this project I only planned to do the deck and it has turned into a full restore. If I looked at this as a full bare hull restore from the start, i feel i would have saved a lot more time and just tore the whole thing apart right off the rip. But i've tried to salvage what i could that is still structurally sound instead.

[Corynelsonflkeys]

Rick, i noticed on your build you had a little bit of wood glassed around the edge of the hull where the cap meets. I had a piece in there as well that was pretty rotten. With the way i'm doing the cap (Like larger models) any ideas or suggestions on how to reinforce it? I was going to add a couple inches of foam where the wood was and glass it to the hull and then reinforce the cap itself with another sheet of glass or two and then brace from the floor up.

[Corynelsonflkeys]

This is the area I'm referring to...

[mshugg]

Foam doesn't really add anything when it comes to screw retention.  You might consider doing what I did on my CCP.  I cleaned out all the wood down to clean glass and laminated in strips 1708, 4 layers aft and 6 in the bow all tabbed in with a 4" strip.  It holds screws just fine and it's rot proof.

[Corynelsonflkeys]

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.

[RickK]

I had 2 bad pieces of wood at the very front of the top rim that I replaced. Otherwise the rest was good. That area you have your hand on looks really thick - is the hull that thick there and below that spot?