Inga Nordic Folk Boat

A new look at canvas decks for wooden boats

Part 3:

Go to part 1   Go to part 2

I have missed my self imposed deadline and hope there weren’t too many people holding their breath.

Small elaboration from page 2

Fungus growth (without one of these wood rot will not occur)

• Moisture – EMC of 20% to 40% (only fresh water, which is why boats are said to rot from the top down).


• Temperature – 10°C (50°F) to 35°C (95°F)


• Oxygen – if you submerge wood in water deep enough where the oxygen levels are low, wood can be preserved indefinitely.

Pattern made for side deck

Article Continued page 3

New decking forward

When Inga’s wooden deck was removed an overall assessment was done to find all areas around fitting and rigging through the deck, especially chain plates, mast and transom (aft chain plates were attached to the transom) where most of the problems were.

All areas that were susceptible to straining from the rig pulling on the boat were areas that water could creep into. The right thing to do is to remove and replace all rotten areas and rebuild those areas anew, some deck beams, half beams, the transom and stem etc., and try building them stronger than before.

Painted V grooved cedar under deck

Because we were covering the deck with canvas, a new deck needed to be put down and plywood was the obvious choice, being strong and dimensionally stable. It was decided to use locally made marine grade fir for the decking. The first step is to make patterns for the plywood, and for this I like to use 2 ½” strips of door-skin ply, fastened together with ½” #6 screws in the corners and cross-braced (I can re-use this pattern material for other jobs later).

When the patterns are made I allow at least one inch overhang on the outside of the hull, allowing room for fitting the cut plywood later. As well all plywood edges were epoxied, sealed and butted on deck beams. The decision was to use ½”marine grade fir plywood with a layer of ¼” V grooved red cedar on the under side to give the look of a laid deck.

Before attaching the cedar, all the plywood decking was dry fit first. Then by tracing the all the deck beams and planking on the under side, it allowed me to glue and nail down the cedar to the underside of the deck so, when back in place, you will not see the nail holes.   Also, with the cedar attached to the deck under side it was easy to paint while off the boat, as the deck beams were left bright.

Tony spreading bedding compound on the deck beams

The decking was then fastened back onto the boat with stainless steel screws, about every six inches in the deck beams and every two inches or closer around hatches and through deck fittings; this was done in combination with bedding it down in a marine polyurethane bedding/caulking (Sikaflex). The counter sunk screw heads were filled with an epoxy faring compound and all sanded smooth.  The next thing is to trim the overhang of plywood to the outside of the sheer planks, using a router or belt sander.

Is there enough canvas?

Then cutting out for mast and hatch holes, I allowed room for the canvas to fold over into those areas. As well, after fitting the decking on the boat, any deck edges under the canvas should be rounded to at least ¼” radius so the canvas won’t wear through, as it would on sharp edges

After all that work was completed, next came the canvas.  Inga was to receive a 12 oz untreated canvas that was 10 ft wide by 30 ft long. This was to cover the whole boat without any seams. First I draped the canvas over the deck of the boat and trimmed off all the excess (with about two feet extra for trimming later), then cut a hole for the deck house. Now backing up a bit, this process of laying down the canvas entails gluing it down to the plywood deck using a PVA water proof glue (Titebond II or III). 

Ironing out the canvas

Starting at the fore deck I brushed on a generous amount of the glue at full strength, no more than two sq. meters (yards) at a time, so the glue won’t have time to tack up. Then lay the canvas into the glue and spread from the center outwards using a plywood squeegee, afterwards (before the glue sets up) gently pulling the canvas outwards (you are not stretching it like you would a regular canvas deck) and stapling all edges of the canvas with stainless or Monel staples.

After letting the glue dry overnight, in the morning I started at one end and with a squirt bottle of water and an iron, I wet the canvas and ironed the whole deck. I took my time and made sure I thoroughly ironed everywhere. This would shrink the canvas and reactivate the PVA to assure a good bond. Then when done I made up a mix of PVA with about 30% water and painted the decks with it.

Roger on his new deck, with new paint

Fred & Nancy redoing Inga’s systems

After allowing it to dry over a few days (this would depend on the weather) three coats of good marine enamel were applied. 

Lastly, all rub rails and deck fittings were painstakingly and thoroughly bedded and mounted back onto the boat.

I have seen canvas on boats that were almost a hundred years old and every time I am excited to see that there are very few problems with the decks and, if anything, because they are able to breathe and work with the boat, they are usually the reason the boats are in such good shape.

Roger sprinkling champagne on the new deck

The reason for doing a glued down canvas on Inga’s deck was that the owner wished to stay as true to the original decking as possible (meaning canvas). 

I have seen this method used on west coast work boats and it lasts for many years under very harsh conditions.  Also the cost compared to epoxies and fancy fabrics was about a fifth the cost, and the toxicity of materials used, the PVA and canvas are very friendly to work with; plus that when the boat reaches the end of its life it won’t leave a toxic pile.

By Tony Grove

Any questions or comments please contact me at info@tonygrove.com.