Wooden Topside Finish

Hi
I own a 36 ft cold moulded (double diagonal mahogany and ply) sailing cruiser; the hull is glued with resorcinol glue and is generally in good condition. The varnished finish has broken down for about 8 ft on the starboard bow section. The rest of the finish is in good condition and could be sanded and re-varnished.
Questions:-
1) Can the finish be successfully patched?
2) What is the best way to remove old varnish?
3) What is the best finish to use, especially considering ease of future maintenance?
4) Could Deks Olje 1 and 2 be used?
5) Could 2-pack polyurethane varnish be used?

 

The dirth of responses here amazes me...

1. IMHO, it will look exactly that, "patched". That is not to say that it will not effectively protect the wood beneath. My limited experience says that there will be a difference in color between the still coated and the uncoated surfaces, after the varnish is applied.
2. Heat. Sanding might well be effective, but not knowing the thickness of the laminations, you can imagine the potential.
3. Tons of choices here, not discounting paint, LOL. Seriously, look for finish with high UV protection. More than a few resources will suggest that an undercoat of epoxy or CPES will prolong the life of the surface coat.
4. I have not experience, can't say
5. Ditto

 

I suggest you determine the exact kind of finish before removing or trying to match it. Deks Olja lets too much humidity in the wood. You'll be better off with West System varnish or other similar product.

 

I would stick with a softer more traditional product like varnish, rather then CPES or any type of urethane coating. The logic being that someday you are going to need to get to the surface of this wood and a hard coating will make that job more difficult, require more sanding and that will increase the risk of damage, by sanding through a laminate or creating an unfair surface because of soft wood getting worn away as you grind down the harder coating material.

Gonzo is correct in that it's wise to learn what you've got there before you plan your attack on the topsides.