24' Fiberform - Rotten Stringers/Transom

Pictures!

Hi All,

here are the pictures! The names of the pictures explain what's going on.

After I took these pictures, we successfully removed 3 stringers.

Also, just for fun, a couple pictures of 'Misty' my Thunderbird Super Coupe.

 

If you hover the mouse over the images it tells you the name of the image.

 

Hi,

Just an update

We have taken out three stringers and I am looking to pre-purchace some supplies.

I have read some posts in this forum about - what to put under my stringers, so no hard spots are created.

I see that some people:

1. Just leave a gap - Water pool...
2. 3M 5200 - easy and expensive.
3. Foam

As far as foam... Any special type I should be aware of?

Thanks in advance!!

 

Just an update:

I'm having the outdrives removed on Friday, and then the engines are being "craned" out on Saturday. This will give me access to grind out the rest of the boat on Sunday.

At this point (Monday) I will be ready to start fiberglassing.

If anyone knows what roving/cloth/mat layers I should do in which order (for the stringers) - for this kind of boat - please send me some tips. I'm not finding too much info on this. It seems professionals don't want to be held responsible for an amateur's job.

So I say: "No expert or amateur's advice will be used against them in the event of a boating accident, whether or not it was due to fiberglass and/or structural failure."

So, you are free to help.

I have heard that the layers should become wider - so that each layer is bonded to the hull. PAR also mentioned that mat is used as a core material that is strengthened by stronger (roving?) fiberglass on the inside and outside of the layers. How many layers?

Thanks!

 

I know I'm offering this a little late in the game for you; but last summer I had similar issues with questionable stringers. They were wet, but not really rotten except for one area where it was cut out for the fuel fill. I opened the top of them to let them breath and dry out for 5 or 6 weeks. Then I epoxied 3 layers of 1708 biaxial onto the existing single layer of roving/mat around the stringers. - It's pretty tough stuff.
None the less, 1708 biaxial cloth is a pretty good choice. I orderd mine from UScomposites.

 

Thanks for the advice, but I had some serious water under all of the stringers. They all need to be removed.

This is a big job, and to ease other's minds who might be doing the same thing, you are not alone. Here are pictures of the engines being removed - to gain access to the transom and the motor mounts.

They used stupid square bolts for the engine mounts, in which I had to buy a special socket called a "gator".

EDIT: The photos are in reverse order. oops The first three pictures are of the truck crane moving the engines. The third picture is the crane operator.

EDIT2: The 6th and the 8th picture show the new stringers that will replace the old ones.

 

Alright,

Another update, for those who are interested:

I was able to track down a professional fiberglasser that was willing to give me a tutorial. He recommends that I use Nytex (mat and biaxle stiched together) over the stringers. With his instruction, rounding the tops of the stringers and creating a curved/sloped stringer base might make it easier to wrap that stuff over the stringer.

Disclaimer: This is what I came up with, which is about HALF of the total fiberglass recommended by the professional.

Stringers:
- Tabbed in with 6oz cloth
- 3M 5200 under the stringer to reduce hard spots
- Encapsulate with 2 layers of Nytex = 2 layers of mat and 2 layers of biaxle

Transom (In order from gel coat to inside):
- Existing hull
- mat
- 3/4" Plywood
- Woven Roving
- 3/4" Plywood
- Nytex
- 6oz Cloth

Bulkheads:
- Encapsulate with 6oz cloth

I will probably change my mind once the fiberglassing starts, but this is the plan so far. If there is any feedback - it is welcome!

Cheers!

 

Tja

Use mat between the two sheets of plywood in the transom. Not woven roving. The mat will bond the wood together much better. Do the baulk heads with biaxial rather them cloth. 6oz cloth is worthless. Two layers over the stringers sounds good accept the motor mount areas. There I would use four layers of the biaxial. It sounds as though the person that has been advising you knows what he is doing. Do it right once and then enjoy. Sincerely, Tom.

 

any progress?

 

Ya! Thanks for asking.

I have been at the dentist too much to put a full effort in, but here is where I'm at:

I have ground out all of the fiberglass, shaped all four new stringers and the new transom. I'm gonna make some chopped strand paste this weekend and fill in some gaps. This is to help me learn how to mix up resin... I'm also going to make a thin resin and soak the stringers and transom with 4 coats of the stuff before I put them in.

The plan is to put the transom in without the layer of nytex and 6oz cloth and to lay a bed of 5200 under the stringers and tab them in with 6oz cloth before I get the fiberglass expert to give me some lessons. This will make sure I don't mess up the structural parts. By this time I will also have a bit of practical experiance.

I used a skill saw to cut the stringers using the old stringers as a template. The curved angle on the bow side of the stringers were also cut with the skill saw with the saw set on a 32 degree angle. (The angle of the hull)

The transom was also cut with a skill saw. I roughly mesured the horizontal top and middle of the transom and the vertical center. Then I roughly cut the basic shape. After placing the new transom board into place, I would see where I would need to 'shave off' more wood. I repeated the process until I had a snug fit. Because the starboard side of the transome required more grinding, the bottom of the hull was 1 inch deeper than the port side. (very thick hull) I shimmed up the new transom board on the starboard side with off cuts. Once this was complete, I noted how much more wood I needed on the starboard side and marked it on the board. I used this as a template for the second transom board and cut it to fit.

The properly cut board is going to go right up against the hull and the shimmed board is going on the inside. This is because the trim tabs screw into the transom very low and I want to make sure they have a firm hold.

I'll take some pictures and post them sometime in the next couple of days.

Cheers

 

this 5200 I see mentioned on the forum- is this replacement foam? I need new foam for my project. can you tell me where to get it?

glad to hear your boat is coming back together!

 

Hi,

I purchace the 3M 5200 at International Plastics. That's also where I get my fiberglass. Due to the size of the project they are giving me contractor pricing.

Places like Home Depot do not have this product... I would check with a local boat repair mechanic to see where he might get some. It is about $20 Canadian for a 10oz tube. This stuff is polyurithane based and is really sticky and tough. It will bind with wood and fiberglass, yet stays rubbery, which makes it a good base for stringers. Keeps the water out too.

I also used it to seal up my hatches, windows and anything I bolt onto my transom. It says on the tube that it can be used under the waterline as well - so I will use it to close up my outdrive seals.

Hope that helped!

 

EDIT:

It isn't foam, or a replacement for it.... but a dam good sealer.

 

I see- well then I will still have to look into it- thank you for taking the time to explain. I'm putting a stern drive in a boat that had an outboard, I could use a good sealant.

Did you encounter any of that bouyancy foam in your boat? Did you replace it?

 

Ya, I encountered a bunch of that stuff. Although I have not replaced any yet, I understand it can be expensive. From what I heard it can be about $25/sq ft. If that is the case, it will cost me $750 to replace all the closed cell foam in my boat. I'm not looking forward to that!