Tsunami / Sceptre topside to liner joint ?

[abl1111]

Just noticed something that I need to repair on my 1975 23' Tsunami and hope I can get some advice from somewhere who has 'been there'.

At the helm, and the passenger side too, there is a topside to liner joint, that runs horizontal, directly under the foot rests - it's hidden behind some teak. This joint is about 1/2" to 3/4 " wide and filled with Potter Putty. Mine is cracked on the passenger side, along the whole horizontal bottom ( the vertical side part seems still intact )

I want to grind this out and re-bed. My questions:

- How deep do I have to grind this ? I don't want to grind too far. Do I grind from the just outside, or inside the cabin too ?

- What would you recommend I fill it with ? I have a lot of resin - can I mix this with cabosil and use that, or is this a good place for epoxy ?

Any advice appreciated. BTW - how I found this was I noticed a little extra movement in the teak door and the door jamb, while closed and under way. I knew something was 'not right'…

[dave3fl]

I had the same issue. I used thickened epoxy and laid a layer of 1708 on top. It has held strong for a couple years, so far so good. I did both inside and outside the cabin.

[abl1111]

I looked at it closer yesterday. There are (7) screws that hold this in place; (3) along the bottom, (3) along the side, and (1) at the bottom behind the door jamb. The screws were all loose.

The thickened 'Potter Putty' that is cracked doesn't 'look' like it was meant to be anything more than a filler ? To fill up the space between the joint between the liner and the topside ? I can't see how it was meant to be have mechanical holding, as their is not prep ( sanding for mechanical hold ) of the liner surface - just smooth gelcoat... Could that be ?

Once I tightened the scows tight, all seems solid.

I think I want to grind out the old Potter goop and re-bed in some thickened epoxy anyway - seems like a good place for stiffness… I might just do the outside though -

[htillman]

When I redid my Sceptre I removed the top cap to replace all the wood under the cap and on the bulkheads. When it was time to reinstall I used 5200 in those seam areas and screwed it. Their needs to be a small amount of "flex and give" in those two areas.

[abl1111]

Hmm.. It should have flex there ? How do you know this ?

[kmoose]

They do flex there and it did not seem to be an issue on mine but because my deck was raised I tied it all in with glass and a short 4 inch tall bulkhead bridge at the bottom of the cabin door. I now have zero movement but it took a lot of non-factory looking glass work to make it happen. I will say it improved the solid feel of the boat. There has not been one crack in the floor or seam and the tower is rock solid with no rattle whatsoever. When you glass everything toghether as one it acts that way.

[htillman]

The top cap is held together with screws and sealant all the way from the stern to the bow. The livewell and transom area is "potter-puttyed" to the hull. I could see looseness in the screws in this area when I removed the top cap. This indicates some form of movement in this area. It gets alot of punishment. Under the storeage areas of the v-berths stress cracking was also found. This is in the inner liner which the top cap mounts to in the area I'm talking about. I do not think it matter whether you use 5200 or glass it, just which ever method you prefer.

[abl1111]

Sounds good guys - Thx.

[abl1111]

UPDATE:
I think the fact that I installed a hardtop this season has made the movement in this area more than what I've experienced in the past 10 years. I will be glassing this in - both sides, starboard and port with epoxy. Then glassing over to make it solid. I don't like flex flex anywhere if I can help it.

[abl1111]

I would like some input on how to make this structural repair so that it is done right.

I am not that familiar with using epoxy for structural repairs ( I've always used poly ) , but epoxy is what I want to use to make the topside and liner " one ". I am quite familiar with the mixing of the West System but not in conjunction with fiberglass cloth.

I want to grind out the old Potter Putty, grind the gelcoat into laminate, prep, then use a syringe to fill in the joint with epoxy and - -

here's my first question - is cabosil the strongest thickening agent ? If not what's better ?-

Then I will have already ground out as much as I can of the joint to make a nice bevel - not 12:1, but the best I can as this area is limited and gets hidden behind teak trim, so I'd like to use the teak to hide the work - then I will glass the joint over with fiberglass - here's the next question;

- what kind of fiberglass material should I use ?

Any other input appreciated.


NOTE: I don;t understand how this area would not be solidly glassed in initially. It's a place that does have enormous stress, so flexibility seems like a bad idea ? Now that I installed a hardtop, the movement in this area, is quite noticeable…

Thank you