23' SeaCraft Transom rebuild

Questions about boat repairs with our resins and fiberglass: hull patches, transoms and stringers, foam, rot etc.
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SkeeterSK
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Post by SkeeterSK » Sat Sep 08, 2007 4:14 am

Do what you want, but I wasnt suggesting it as a show peice. If you just wanted looks there are plenty of halfassed suggestions that could have been given..

I was trying to say what I beleive would be strong. A panel screwed down to another panel that gets alot of shear loading does not seem strong in my opinion. But if some drywall screws, 5200, and some small peices spit and glued together sounds stronger than a single large peice of 1/2" or 3/4 Meranti thats bonded to the stringers and the edge, more power to ya :lol:

I dont use my boat to make money. On the other hand, I have a 50-60hr week day job and run a business as well so I desperately need my boat for its relaxational qualities before I have a stroke or something. I want nothing more to get it together again, but it seems like such a waste to me to spend weeks taking something apart and totally halfway the repair because I dont want to spend another couple of hours. Just my take on it.


Be a pro at fiberglass, GET SKEETER!!

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Post by john_b » Sat Sep 08, 2007 8:25 am

The 9' x 28" panel in question has been recored with 3/4" high density epoxied composite core, and is probably much stronger and lighter than a plywood base structure. Originally, it was cored with balsa, and that lasted almost 20 years, I am sure the composite reinforced version will make it at leat that long.

You do have a point with the attaching the cover with screws, and caulking it it. I think what caused the problems was the attachment point, being the lip of the liner around the edge was moving around, and it is all solid now. 1000's of boats in this era used the same design for this center fuel tank cover, and as long as the cover didn't fail, and the mounting points where solid, they held up just fine for many years. After I get it back together, and am satisfied with the water test, I may stitch the cover in with epoxy. IMHO, recaulking this with 5200 will probably be sufficient. When they were new, back in the 80, I believe they just used silicone marine caulk.

I am not changing any of the design on the boat, just replacing, repairing, and reenforcing areas with epoxy and meranti wood. After all, it lasted almost 20 years. If it makes it another 20, great. It took 4 different points of failure before anything was really noticeable, and I have addressed/repaired all 4.

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Post by john_b » Sat Sep 15, 2007 9:01 pm

Well work is coming along slow but steady.
- I have repaired the stringers, and retied them to the hull.
- I have leveled, repaired and glassed in the sole to stringer connections on both side of the fuel tank.
- I have replaced the forward and rear bulkheads in front and behind the gas tank.
- I have put in the new gas tank platform, and have the transom cores cut and ready to put in.
- I have the donor panel made for the outer transom cutout fill in.

In case you haven't seen what a mold table looks like, her is a picture of what you can do with an old sliding door
Image

Here is the before and after of the sole "floating" on top of the stringers, where it is now solidly attached.
Before - the sole just had glass putty stuck under between it and the tops of the stringers, it had come loose in several places, and wasn't level.
Image
After - it now feels like you are standing on concrete.
Image
Here is the fuel tank deck and bulkheads put in. Notice the 2 notches to let water in/out. I am going to put the gas tank on 1/4" neopreme strips, and attach it with mounting brackets to the stringer, no more foam to hold water.
Image

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Post by john_b » Sun Sep 16, 2007 8:38 pm

I will be putting in the plywood coring into the transom this week.
I plan on using peanut butter consistancy epoxy thickened with wood flour applied with a 3/8" notched troll. What would be the best thickness for the plywood to outer skin bond. The skin is pretty rough, but has been evened out so it should be uniform in thickness. I was thinking about 1/4".
Same question for the bonding between the 2 pieces of plywood, I was thinking a little thinner epoxy mix, and 1/8" of an inch.
My intention is to put in spacers to maintain the thickness.

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tech_support
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Post by tech_support » Mon Sep 17, 2007 8:08 am

Its looking good, your sole to stringer patch should hold up well.

For laminating wood, you should use a thinner mix of epoxy/wood flour thatn what you used for the fillets - more like mustard.

Also, pre-coat the wood faces with straight epoxy first, let it soak in a bit and tack up - then apply you glue with the notched spreader.

The notched spreader makes it very easy to get the glue applied evenly

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Post by john_b » Mon Sep 17, 2007 12:04 pm

shine wrote:Its looking good, your sole to stringer patch should hold up well.

For laminating wood, you should use a thinner mix of epoxy/wood flour thatn what you used for the fillets - more like mustard.

Also, pre-coat the wood faces with straight epoxy first, let it soak in a bit and tack up - then apply you glue with the notched spreader.

The notched spreader makes it very easy to get the glue applied evenly
So, what is the best guess for thickness in this coat, 1/4"? 1/8"?
I like using spacers because you get an even thickness, and it keeps you from squeezing out too much epoxy. I have seen alot of transoms where the wood either wicked up, or the laminates/cores were over compressed and squeezed out the bonding material. This boat had that problem on one side of the transom.

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Post by tech_support » Mon Sep 17, 2007 12:37 pm

The unthickened coat is very little, 12 oz would cover an entire 4x8 sheet. The glue layer (thickened is the smallest trowel notch on the West system spreader) I will go look and get a measurement

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Post by tech_support » Mon Sep 17, 2007 12:42 pm

its 1/8". Use just enough pressure to hold the pieces flat.

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Post by john_b » Mon Sep 17, 2007 7:36 pm

shine wrote:its 1/8". Use just enough pressure to hold the pieces flat.
Thanks, that was what I was looking for, I will put in 1/8" spacers then.
I was able to get the cutout fillin outer skin tabbed in today.
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Post by sunkShips » Tue Sep 18, 2007 4:14 pm

Is that gonna hold the Motor? I would think it would rip right off! 8O

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