Rebuilding an old Riva - advice

Questions about boat repairs with our resins and fiberglass: hull patches, transoms and stringers, foam, rot etc.
TomTom
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Rebuilding an old Riva - advice

Post by 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…

Image

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fallguy1000
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Re: Rebuilding an old Riva - advice

Post by 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.
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fallguy1000
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Re: Rebuilding an old Riva - advice

Post by 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.
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TomW1
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Re: Rebuilding an old Riva - advice

Post by 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
Restored Mirror Dinghy, Bought OD18 built by CL, Westlawn School of Yacht Design courses. LT US Navy 1970-1978

TomTom
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Re: Rebuilding an old Riva - advice

Post by TomTom »

TomW1 wrote: Thu Jan 27, 2022 6:15 pm 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
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Re: Rebuilding an old Riva - advice

Post by 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.
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