Varnish for a teak rudder?

[Ship'sCat]

My Halcyon 23 is a fibreglass yacht with a teak rudder. I bought it the year before lockdown so haven't been able to complete a few things before she goes back into the water. The varnish on the rudder and its stock has bubbled in places. Before I get on with stripping, sanding, & re-varnishing I wonder if anyone can advise whether a special varnish is recommended or can I just get on with using regular varnish from my local hardware store?

I don't quite understand the science behind the notion of varnishing the rudder, because as far as I know varnish is not waterproof and would if anything trap water behind it as it gets through. On the other hand I suppose a varnish would prevent algae and sea creatures getting in, and in any case the rudder can be taken out of the water between weekend sailing sessions (although I may eventually get to go further afield, hopefully).

 

[Rappey]

Wooden rudders are often fully painted.. Varnishing exterior teak is a bit of a lost cause as teak is very oily and varnish and teak do not go well together.. Coating teak often promotes spores to grow under the coating and it often cracks and comes off.
Saly water is good for teak as it kills bacteria that thrives in fresh water that rots wood.
There are coatings some use but its far from a "fit and forget" solution.
If you remove the rudder as you say, then varnish should last a lot longer..

 

[Tranona]

The underwater part should be painted - 4 coats of Primocon, antifoul then antifoul. It is common to varnish the above waterline part because it looks good. Sand it back to show a clean surface and natural colour then degrease with white spirit and use a porous coating such as International Woodskin. This will last for several years with the od rubdown and recoat. You can of course paint it with Primocon, undercoat and top coat enamel if you don't like the shiny look!

 

[Ship'sCat]

Thanks for these from both of you. The boat has spent a sheltered life, and I don't think it has been afloat that much. It is still mainly as per delivery spec with original teak hatches, coamings and rudder, deck fittings. It is clear that the rudder came from the factory varnished. So I need to decide whether to go for practical paint on the one hand or original varnish for the sake of authenticity on the other ........

 

[Tranona]

Depends on whether you are going to keep it afloat. If so then the rudder definitely needs the same antifoul as the rest of the hull. If the teak above the waterline is already varnished then keep it that way. If you do need to strip back to bare wood suggest you use Woodskin rather than conventional varnish as it is easier to apply and longer lasting.

 

[Quandary]

Our boat has teak handrails and companionway trim, the only teak exposed on it, I have been using Woodskin for four years now, the slightest contact such as stowing a boat hook along the rail damages the coating so it has to be sanded and recoated every year, despite the boat being covered for 5 months in winter, not a product I would recommend for exposed teak. ( And I did prepare it carefully before the first coats were applied,) I do not like the pigment either but I suppose if it was clear UV would have had it gone even sooner.

 

[Rappey]

Trouble with woodskin on any wood is it goes hard then chips off.
Try to redo the damaged area and it's a completely different shade.

 

[MADRIGAL]

In the world of classic sailing dinghies like the Wayfarer, early wooden models of which are still raced competitively with more recent GRP versions, it is common to cover wooden rudders with epoxy and woven glass mat. The glass-and-epoxy layers are virtually transparent (I think only one or two layers of glass are used with several coats of epoxy painted on) and water-tight. They certainly look like they have been varnished. There are descriptions of the DIY technique on the UK and Canadian Wayfarer sites. I wonder if this might work for the Ship’s Cat if the intention is to keep the varnished look.

 

[Ship'sCat]

Our boat has teak handrails and companionway trim, the only teak exposed on it, I have been using Woodskin for four years now, the slightest contact such as stowing a boat hook along the rail damages the coating so it has to be sanded and recoated every year, despite the boat being covered for 5 months in winter, not a product I would recommend for exposed teak. ( And I did prepare it carefully before the first coats were applied,) I do not like the pigment either but I suppose if it was clear UV would have had it gone even sooner.

In the world of classic sailing dinghies like the Wayfarer, early wooden models of which are still raced competitively with more recent GRP versions, it is common to cover wooden rudders with epoxy and woven glass mat. The glass-and-epoxy layers are virtually transparent (I think only one or two layers of glass are used with several coats of epoxy painted on) and water-tight. They certainly look like they have been varnished. There are descriptions of the DIY technique on the UK and Canadian Wayfarer sites. I wonder if this might work for the Ship’s Cat if the intention is to keep the varnished look.

My dinghy is a Mirror so I understand your point. But I am wary of putting anything almost-watertight around this rudder in case it just traps moisture within. The thing about the existing varnish is that the actual teak underneath is in great condition but with no decay.