Rebuilding an old Riva - advice

[TomTom]

A friend is restoring this Riva run about. He has taken all the rotten plywood out and also the rotten ribs and replaced them.

He says there was a funny sort of waxy canvas between two layers of plywood (which I believe was planked diagonally at 90 degrees to each other)…

He is asking for some advice on the rebuild …

As it is almost a completer rebuild I am inclined to suggest that he use epoxy and encapsulate all the ribs and “cold mold” all the strips and then sheath the outside at the water line with biaxial…

But I don’t know enough about whether this would be possible/ compatible with what is left or whether he should copy the original system of fasteners, waxy canvas etc…

I don’t think he is looking for it to be restored as original necessarily…

[fallguy1000]

I don't know a ton about the material, but generally, that is canvas. And it might be painted with lead paint..

no on glass

This a classic wood boat. There is a West System restore technique for wood boats. I believe each plank is coated in epoxy, but then they would not swell and close; so I must only be telling part of the how.

[fallguy1000]

The purpose of the painted canvas was to slow the water rushing into the hull down so that the planks could swell and the water stop. Kind of a damn of sorts.

Not my area of expertise. I had a wood boat years ago I cooked on the fire.

[TomW1]

Tom Riva's are top of the line Yacht's so I would recommend that he use all epoxy and the best marine ply he can get. Did his boat come with an inboard, a lot of Riva's were powered by them. So, set him up with marine ply and epoxy and fiberglass to repair that baby. It will be a beautiful boat when finished. By the way what is the length of his Riva?

Tom

[TomTom]

Tom Riva's are top of the line Yacht's so I would recommend that he use all epoxy and the best marine ply he can get. Did his boat come with an inboard, a lot of Riva's were powered by them. So, set him up with marine ply and epoxy and fiberglass to repair that baby. It will be a beautiful boat when finished. By the way what is the length of his Riva?

Tom

I believe the boat has an inboard yes. I have not seen it - but I would guess its about 20 foot in length and was built in the 60's.

As I said - I am inclined to suggest he uses all epoxy and glass - I think that would be easier than trying to imitate the old build technique.

In answer to Fallguy - I believe that when using epoxy encapsulation of frames/ planks on an old boat that needs to swell to become water tight, one technique is to use uncoated wooden wedges/ small strips between the encapsulated planks - these then swell to fill the gaps - a bit like caulking - but the main planks and frames are protected. As this is not a planked boat but cold molded from what I understand, this would not be applicable.

In the case of this boat my feelings is that it would be easier to glue the whole thing together with resin and glass in a rigid, non-swelling way, basically like a ply on frame boat.

[fallguy1000]

I don't believe the West System bottom uses glass. Read up on it. The classic Chris Craft restoration guys always sell boats with 'West System bottoms to waterline'.

Based on the pictures; the boat is a perfect candidate for a West System bottom versus a double planked, painted canvas one.

Let me know if I am wrong on the West System bottom. I do NOT know how it is done really well.