14' trihull floor replacement

My 14' fiberglass trihull has a rotten floor. I need to remove the fiberglass liner and remove/replace the wood below. Looking for advice from those who have done something like this. Where exactly should I cut when removing the fiberglass? Right at the edge of the floor? Leave a lip? Or, should I make the cut under the rubrail and lift it all out, including the sides and gunwhale? Any advice appreciated.

 

Normally you would remove the liner completely. Looks like you already started cutting it in pieces, which will require building a liner from scratch. What is your skill level on woodwork and fiberglassing?

 

That was a cracked piece inside the gas locker that I used to expose the problem. Otherwise the liner is intact. My wood skills are pretty good, but new to fiberglass. I have no idea how these liners are typically attached. If I were to cut all along the rubrail, for example, could I expect that I could put a some overhead block and tackle on the cleats and lift it upward? Or do they glue/epoxy it in? If they do that, I can't see how I would get under it to detach.

 

You shouldn't need to cut. There are screws or rivets on the rubrail that also hold the hull/deck joint. Sometimes there is also adhesive though. Closeup photos of the joint will help. Take some from under too.

 

Leaving a lip is also an option. But I would not if rotten. The thing is, you will need to bond cleats to the sides if you remove the lip is all.

Removing the entire liner would probably go poorly, but it all depends on the extent of rot and if you have a means to lift it without damage, etc.

 

Fallguy’s warning about removing the liner intact is very valid.
You might want to invert the boat before separating the liner from the hull, supporting the liner appropriately off the floor, then lift the hull up and off.
Have you sounded the rest of the floor to determine the extent of the damaged core?
The damage shown does not appear to be part of the inner liner, and may not represent the entire deck.
Many similar boats are foam cored, could this be the case here?
Also be aware that the cost of restoring this vessel may be far more than it will ever be worth.

 

Thanks. I removed the rubrail and the screws that connect the deck to the hull. That overlap connection is still quite solid (The photo is looking at the transom). I am guessing sealant or adhesive? What would you suggest as a next step (assuming I want to take the deck off in one piece). Heat gun and a thin blade like a painter's tool/spackling blade? Or an oscillating tool? Something else?

I have it in a large shed where I can use pulleys from overhead to lift the liner out, evenly...hopefully without applying any torque to it.

Thanks.
John

 

I have in in a shed where I can bring down pulleys from above to lift the liner. As an alternative to using the cleats cleats, I was thinking I could slide some 2x4s under it for lifting, to reduce torque and get more even support.

Appreciate any advice.
John

 

I sounded at the console and it was saturated. In the gas tank locker, it was a mix of wood on top and closed cell foam between the stringers. I read somewhere online that ProSports didn't stop using wood completely till '97, and this is a '90.
Unfortunately, inverting the boat is way beyond what I can do, as it is extremely heavy. I think all that saturation is playing a role, but it was pretty heavy to begin with.

 

Actually, I was wrong about there being adhesive. I can slip a flat drywall blade up through the joint to the top of the gunnel. It's a tight fit all the way around, but apparently no adhesive or sealant.

I still need to free up the liner at the transom. But it looks like it might only require relaxing the bolts on the motor, not removing it. We'll see. (plus disconnecting cables)

Next would come an attempt to see if that liner will budge. I was thinking about using a block of 2x4 to gently hammer on and see if I can get it to slip upwards any. Maybe simultaneously with some upward pull on the cleats? I don't want to screw this up and crack it.

Any advice appreciated!

 

We usually used chain falls or cable pullers to lift the liner. First put some tension and then start prying and tapping.

 

Thanks. Do you think tension on the cleats would be ok? I dont really have anything else to attach to.

 

That is a good attachement point

 

Hey Gonzo,
I am seeing that there are some places where it looks like the liner is glassed to the hull. In particular in the gas locker below the motor well (also the storage area below steering Console). Attaching some photos of that locker area. Would be interested in your advice as to how you would approach it. I don't want to go off half cocked with a cutting wheel, especially since I will have to re-glass this when done. video: https://youtube.com/shorts/ej-zvlTdD9E?feature=share
Thanks,
John

 

You’ll want to remove the motor and pretty much everything else that’s not an integral part of the hull or cap.
Removing the angle between the motor mounting lip and the transom top may show you more about how the two parts are married.