Ive just obtained a wooden planked IOM The hull is in need of a re varnish . I would like to keep the natural look so looking to re varnish. Obviously a good sanding to remove the old stuff.

Is yacht varnish the stuff to use or is there some thing better. Does the raw hull need any sort of sealer before varnishing etc Or does a sealer go on top of the varnish

I believe the hull is Mahogny

One is astonished that no one has replied to you.

For what it is worth

I have only owned 3 wooden planked boats and that was 15 years ago at least. I never Varnished any of them.

I have always used Epoxy Resin - Z Epoxy Finishing Resin to be precise. it is low viscosity ( thin ), easy to apply, hard wearing and above all light and hardens quite quickly 2..3 hours at most

It is almost clear tending to slightly brown.

But in spite of it being a yacht you do not really need a marine varnish / coating i.e. C5m class finish.

So using a DIY finish will be just as good but not particularly hard wearing.

The problem will most be the existing coating and will the new coating key to it. But do you care !

At least use a block when rubbing down

...

If you are thinking of coating the hull with epoxy you might try XCR Epoxy Coating Resin available from Easy composites I have had great successwith it.

url http://www.easycomposites.co.uk/#!/resin-gel-silicone-adhesive/epoxy-resin/epoxy-coating-resin.html

It polishes up beautifully.

whilst a,one pack varnish or coating will sit on most base coatings, my experience of two pack is that it reacts badly to overcoating either one pack or traditional finishes. surface prep needs to be carefully done if two pack is not to abandon ship.