1984 Four Winns rot under ski locker

[The Car Doctor]

My boat is a 19' Four Winns Horizon and this summer I've noticed the lovely decomposing wood smell every time I opened the ski locker. Now that the season is over, I've decided to spend the winter working on it. After opening things up, I found water logged foam under the floor of the ski locker and the fuel tank. The keel stringer is soaking wet and falling apart. It seems to me like this is a lousy place to put in foam. Shouldn't very bottom of the boat should allow water to drain freely into the bilge.

My question is what if I leave the foam out of this after my rebuild? Also, what if I left the floor out of the ski locker to give me a few more inches storage space? Would it be bad to have stuff stored directly to the bottom of the hull?

 

[Chinnookered]

My 03 Glastron GX205’s ski locker doesn’t have anything but hull. As far as foam goes, many people leave it out. I know I’m not putting any under the floor in the 90 Bayliner Cobra I’m just starting.

 

[The Car Doctor]

Does yours have a keel stringer?

 

[Chris51280]

Some have stringers in the center and some don't. I would not eliminate stringers since they are designed for a purpose. Also, foam is needed and I would like to have enough to make sure if it takes on water I won't have to recover it from the bottom of the sea floor. I have a drain that goes with a 3/4" pvc pipe to the engine bilge under the tank area

 

[chevymaher]

I like foam. I have the same basic boat you do. Put it together right. And dont fill it with water.

 

[The Car Doctor]

Some have stringers in the center and some don't. I would not eliminate stringers since they are designed for a purpose. Also, foam is needed and I would like to have enough to make sure if it takes on water I won't have to recover it from the bottom of the sea floor. I have a drain that goes with a 3/4" pvc pipe to the engine bilge under the tank area

Do you have a picture of the PVC drain or could you describe it a little further? Does it have perforations in it to pick up water? If so, how do you keep the foam from plugging the holes?

 

[The Car Doctor]

I'm trying to determine how thick of fiberglass skin I need over the new stringer. The old one had an average thickness of .135" of chopstrand and I assume polyester resin. I will be using epoxy and I have 9 and 17 oz biaxial on hand.

I'm hoping someone knows of a formula or chart (if there even is one) for comparing the strength of polyester and CSM versus epoxy and biaxial e cloth. For example, if I have a thickness of .135 of CSM and poly, how much thickness of biaxial and epoxy do I need to achieve the same strength?

 

[Chris51280]

look at post 235 and 237
https://forums.iboats.com/forum/boa...or-transom-stringer-upholstery-project/page16

 

[Chris51280]

look at the stickies on how to work with epoxy and polyester resins. chopped strand is used with polyester resins since it chemically bonds with the resin. I'm not a chemist but there is a reason for it. You will just waste epoxy with csm and it will become more expensive. epoxy is used with 1700 and other woven fabrics

 

[Lou C]

I think that stringer supports the keel so I would replace it and add foam when done. I did the deck and some of the stringers on mine about 12 year ago and did not have to fix that but might in the future. There were a couple of plugs they used to inject the foam and they probably allowed water in unfortunately.
When I contacted F/W back then about the foam they said it was both for sound deadening and structural support and shoud be replaced in a rebuild.

 

[Scott Danforth]

your 1984 four winns was designed with a 15 year life expectancy like nearly all pleasure run-abouts

it is now 36 years old.

rebuild it the way it came, simply making sure your wood is well encapsulated and it will be around another 3 decades

the answers to all fiberglass questions are in the DIY links at the top of the stickies

specifically links 14, 15, 18, 2, 3, 4a, and 4b

 

[kcassells]

I'm trying to determine how thick of fiberglass skin I need over the new stringer. The old one had an average thickness of .135" of chopstrand and I assume polyester resin. I will be using epoxy and I have 9 and 17 oz biaxial on hand.

I'm hoping someone knows of a formula or chart (if there even is one) for comparing the strength of polyester and CSM versus epoxy and biaxial e cloth. For example, if I have a thickness of .135 of CSM and poly, how much thickness of biaxial and epoxy do I need to achieve the same strength?

poly or poxy

Always run 2 full glass coats 1700 top to bottom with 1700. Then 3" tab then 6" tab 1700. They can be smaller given the "box" of the stringer and bulkhead. Cap the top with the lighter weight glass. No body measures thickness cause everyone is slopping in resin dif than another.
I just ran glass complete inside the box side to side front to back. So that was also my tabbing. see?

 

[The Car Doctor]

I tabbed in one layer of 9oz and three layers of 17oz and ran all of them all the way to the top of the stringer. Is that enough?

Also, does modern two part flotation foam allow water to drain out of it? If I fill my keel area with foam and for some reason it got water in those chambers, would it drain out?

 

[Chris51280]

the marine foam is closed cell..... for a time being. The old discussion about drain holes in stringers and bulkheads. Some do it and some don't. Most decide against it. If you do a good job sealing it off, no need for drain holes.

 

[Chris1956]

I had a similar issue on my SeaRay. The original keel stringer was a 2" tall X 3/4" piece of plywood, stapled to the bottom of the ski well. The staples rotted out and the keel stringer fell over, causing the hull to collapse a bit.

My structural assumption was that the bottom of the ski well supported the keel stringer. Thus the sides of the ski well supported the bottom of the ski well, and the deck supported the ski well sides.

I would therefore recommend you cut out the entire bottom of the ski well, and any rotten wood on the sides of the ski well. Dig out all the foam, and clean and sand the inside of the hull. Hopefully most of the foam is dry, or you could have more issues further back in the hull.

Make a new keel stringer out of dry pressure treated lumber and bed it to the hull with polyester putty or poly resin and chopped cloth. Now cover the keel stringer with glass and seal it to the hull as well. Now repair the sides of the ski well to support the bottom of the well and keel stringer.

Foam the void, up to the bottom of the ski well sides. I used cleats on the inside of the ski well, to hold the ski well bottom to the sides, with SS screws. So paint the new skl well bottom (bottom and edges) with poly resin and drop it into the ski well. A couple of SS screws thru the ski well bottom, into the keel stringer is advised. Screw the cleats to the ski well sides and cover everything with cloth and poly resin.

Obviously, make sure the deck is solid and firmly attached to the ski well sides.

Poly resin is fine for this repair, as there is plenty of surface area for glass and resin to adhere.

My repair lasted until I sold the boat many years later.