Varnish, PU or oil for gunnels?

I’m considering finishing my ash gunnels with marine varnish or outdoor polyurethane to reduce annual maintenance. However, I know there are mixed views about using either varnish or PU instead of the more traditional oil. I’d appreciate any opinions or input about any of those three finishes.



my opinion is a long story

Oil fer dis boy’s gunnels
Soaks inta de wood an’ not just a coating on top of it. Erlin’ is a nice relaxin’ thing ta do once or twice a year fer me. Varnish or poly “may” develop micro fractures dat “may” allow moisture in under de coating an’ discolor or promote rot in de wood.


Varnish is MORE work
Ultra violet light is the enemy of any wood finish. Eventually it causes finishes to break down and then they need to be re-done. The problem with varnish on gunwales is that it forms a film which can crack and hold moisture and eventually flake off due the ultra violet light degradation. While traditionally bright-work on boats has been varnished it requires almost constant upkeep (scrapping, sanding and re-varnishing). The problem with varnish is that it allows light to pass through it, the light is then reflected off the surface below and attacks the film from the underside – this causes cracking and allows for moisture to get in. It’s a double whammy – light degrades varnish films from the top and from the underside at the same time.

Penetrating oil type finishes on the other hand do not form a surface film and do not flake off like varnish finishes. In the end penetrating oil finishes are longer lasting than varnishes and require less upkeep.

Keeping your wood-trimmed canoes stored out of the weather does a LOT to prolong the life of wood trims. Always store your canoe indoors when not in use.

Many people use prepared “rubbing oil” finishes like Watco, I prefer to mix my own finish using equal parts of boiled linseed oil, turpentine and spar varnish (or poly if that’s all I have on hand). I apply the oil mixture, let it set up for a few minutes then rub off all the excess. I leave it alone for an hour or so and go back and rub off any more that has soaked back out. I wait 2 or 3 days and do this all again. A third coat might be needed on very dry wood. I “sand” between coats with an abrasive pad (Scotch-Brite type). Personally I enjoy re-oiling the wood trims on my composite canoes. I take pleasure in seeing the wood trims “come back to life”. I like to pay attention to the condition of my trims & never let them get to the point where they are starting to gray out and weather stain. Each year I do a thorough re-oiling job on each of my wood trimmed canoes and I also do periodic spot oiling through the season as needed. It’s no big deal – it’s just part of owning nice looking boats.

For less upkeep get a canoe with aluminum or vinyl gunwales.

Regarding oil finishes
I’ve heard this said: Apply once a day for a week, once a week for a month, once a month for a year, and once a year forever. That was in reference to furniture, though.

Tung oil
All the different options have pros and cons and wood trim is beautiful but demands attention. If you leave a problem it just gets worse. If It gets really bad you have to replace all or parts of the wood.

I use pure Tung oil diluted with mineral spirits. More diluted to start out with so it penetrates better. I usually do 3-5 applications a season one or two coats.

I have had canoes with varnish, but the wood can rot under the varnish if it gets scratch with water in it.


– Last Updated: Mar-13-07 11:36 PM EST –

For the past 5 years I have used nothing but Watco on my wood trimmed canoes. I have had no problems as a result of using Watco, and I have quite a few wood trimmed canoes. Matter of fact; I just put 2 coats of Watco on the trim of my Mad River Courier this weekend.

Is it the best product?
I don't know, but it has worked for me.
I'm sure that all my canoes being stored inside is a very important consideration.


I think real marine varnish gets a bad rap. It’s been going on boats for a couple of hundred years. It is a UV barrier. That’s why people put it over epoxy.

I only have the touch up the varnish every few years or more, if then. Then you just scuff it and give it a fresh coat.

I see 50 - 60 -70-80-90-100 year old canoes all the time. Most of the time the rails are in good shape, except for the tips where the canoe was shingled on the ground and the ends rotted. Even wonder oil ain’t gonna save a canoe then.

Good spar varnish works well.
It is the manpower aspect that is a drag. Varnish worked well for the British Navy, and at one time they ruled the world.

Of course, they had lots of available hands that needed work to occupy them on long voyages. Me, I’m lazy. Watco for the lazy boaters!


I’m just as Lazy…!
Okay, so every 3 to 5 YEARS maybe 10 years if I get real lazy, I gotta find a piece of sandpaper, run over the gunwale with it, find a tack cloth, open the can, insert brush, dab a little golden varnish on the rails, let dry, open beer.

You oil folks are talking about finding the can and running the oil all over the rails multiple times per year…gawd that could require a 12- pack per year easy!!!

Rail finishes
We currently use spar varnish, a poly urethane, because some many customers will not keep up with oil.

That said, we are testing cherry rail sections treated with Spar Varnish, Watco and Armada. Sooner or later, someone will ask the same question and we’ll have a definitive answer.

If cost is any indication, Armada or Cepatol are the priciest options, but they require sanding and starting from scratch with three coats.

Deks Olje
I am still owned by a traditional sailboat. Since I love the look of well-cared for wood on a boat, I’ve tried a lot of wood finishes. Most involve a dreadful amount of fuss and bother. I was delighted to stumble upon a product called Deks Olje produced by the Flood Company. Available in matte and glossy finishes. I prefer the matte which gives outdoor wood a very natural well-kept look.

It’s easy to use and, unlike nearly every other product, has no downside that I’m aware of. With it, you’re not setting yourself up for a lifelong regimen of sanding and re-varnishing.

Deks Olje?
I’ve never heard of that product. What’s its indredients; PU varnish, oil based varnish, tung oil based or something else? I’d also be interested in how you think it holds up against sun and water.



Oil is easiest
I don’t think oil is the best but it only takes five minutes to apply and their is no sanding or bleaching or cleaning required. I like varnished stuff if you are not going to be scraping it against things, but the varnished gunnels on my guide boat are drying me crazy because of the roof rack rubbing them! They are really a pain to sand and touch up. I wish they were just oiled. I since they are vented gunnels I’d have to unepoxy then to get all the varnish off and start over with oil.

Wood boats are a PAIN!