1970 Stamas clearwater 24' rebuild

Crawson89

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Joined
May 10, 2022
Messages
4
Hey! First post here, been reading for years!

After completing a refit and refinish of my 1969 viking 22 sailboat, bulkhead replacement, sole replacement, re-coring and spraying fresh gelcoat across the entire topside, I have acquired a 1970 Stamas Clearwater 24' project. I had planned to flip for the value of the trailer, but her lines grew on me, and I've committed.

I am an experienced glass/gelcoat tech and apprentice marine mechanic. I'm comfortable with a project of this size, with dealership access to parts. Have a gm 305 5.0L v8 and alpha 1 gen 1 in good working order to drop into the boat. Originally came with a mercruiser "160" which I cannot find much info on but believe it would've been a ford inline 4 and pre alpha drive. All electrical is already designed and mostly purchased.

I'm currently in the demo process and have removed rotten cockpit sole and am deciding how to proceed with these stringers.. after speaking with Stamas i was expecting solid Doug fir stringers, but came up with foam filled glass stringer/bulkhead skeleton. It appears to have been laid up in a mold upside down, and filled with foam. Then flipped over and glued into the hull. The foam core does not extend all the way down to the hull. The foam coring has de-bonded from inside of stringers, how structural do we think the foam is? I was planning to tab the stringers down, as I'm not happy with original bonding putty holding it all to the hull, but wondering if i should be grinding out all the foam from 6" access holes, refilling with expanding foam and capping with glass before the new floor goes on...

Also, toying with idea of using 1/2" nidacore to replace old 3/4 ply waterlogged floor? Thoughts?

Open to all constructive guidance, opinions, thoughts etc!

Thanks!
 

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mickyryan

Captain
Joined
Apr 18, 2016
Messages
3,865
go to back of boat by where stringers attach to the transom and drill a couple holes to see if holding water lots of time foamk will dry out if there is holes to let water escape
 

Scott Danforth

Grumpy old guy who plays with boats
Joined
Jul 23, 2011
Messages
39,028
Mercruiser 160 was a 250 cubic inch GM inline 6. The drive was an MC1.

There is no "pre alpha" drive. However there are 17 various drive models that were used before the Alpha drive

The keyhole cutouts are similar

Agree with micky on the test drills
 

tpenfield

Supreme Mariner
Joined
Jul 18, 2011
Messages
15,340
Following . . .

The foam within the stringer grid is probably not all that structural IF (if) the stringer grid is in good shape otherwise. Do suck the water out with some drill holes (as mentioned) and maybe even tilt the boat to the holes and apply suction from a wet vac.

As far as the nidacore for flooring . . . probably the better bet vs. high density foam. You certainly will want to adhere the flooring to the stringer grid and glass it to the sides of the hull at the chines.

You may want to fill the chambers of the hull (that the floor and stringer grid create) with foam, much like the traditional wood/glass construction. It will give the boat a more solid feel and perhaps give you enough flotation.
 

kcassells

Fleet Admiral
Joined
Oct 16, 2012
Messages
7,960
Nice boat!
The foam in the stringers is basically not for strength. When done there are like 6 layers of glass over the foam for strength. You could easy scalp the tops off to remove foam and then pour new foam back in. After you cut the excess foam to height then roll or brush resin over the open cells so they become closed cells.
Also agree to fill foam in the other cavities or make storage. I've never used nida core. It is definitely more expensive and labor intensive. Here is a thread on guys who used it.

Also here is a read on the various types of 2 part marine foam.
 

Crawson89

Recruit
Joined
May 10, 2022
Messages
4
Thanks for all replies and suggestions! Spring yard cleanup has halted progress for a week, but will start drilling access holes and exploring further! Will post progress soon!
 

kcassells

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Joined
Oct 16, 2012
Messages
7,960
Thanks for all replies and suggestions! Spring yard cleanup has halted progress for a week, but will start drilling access holes and exploring further! Will post progress soon!
Yup same here. Cleaning up the yard.
 

Crawson89

Recruit
Joined
May 10, 2022
Messages
4
Hey Scott, any idea what the original mounting pattern looked like in the mercruiser 160 vs a 305 v8? My plan is to drop the motor in and align it with the alpha transom assembly while hanging, then measure positions for front motor mounts, motor back out and build the new engine stringers then motor back in.. Any simpler way you can think of to get front motor mount positions for new engine stringers?
 

Crawson89

Recruit
Joined
May 10, 2022
Messages
4
Mercruiser 160 was a 250 cubic inch GM inline 6. The drive was an MC1.

There is no "pre alpha" drive. However there are 17 various drive models that were used before the Alpha drive

The keyhole cutouts are similar

Agree with micky on the test drills
Hey Scott, any idea what the original mounting pattern looked like in the mercruiser 160 vs a 305 v8? My plan is to drop the motor in and align it with the alpha transom assembly while hanging, then measure positions for front motor mounts, motor back out and build the new engine stringers then motor back in.. Any simpler way you can think of to get front motor mount positions for new engine stringers?
 
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