What to do when deck covering leaks

Re-laying a canvas deck on canvas and sheathed wooden decks.

A fabric-covered deck will remain watertight and look smart for many years, provided it is correctly fitted and properly maintained.
The most common causes of a leaking deck covering are listed below:

1 Abrasions and tears in the deck covering. Joins in the canvas and lumps beneath the covering will be subjected to greater wear than the rest of the deck. Tears, which are particularly common on the foredeck, will also allow water to seep in beneath the deck covering.

2 Abrasions will also occur where the deck planking beneath the covering has swollen, causing the canvas to stretch over a sharp edge, where it will be vulnerable to increased wear. Tongue and groove planking often lifts in this way, because the boards are wider than those used on strip laid decks, making them more prone to cupping.

3 Tears will almost certainly occur where the deck covering is bonded tightly to the deck planking. Provision must be made for the movement of the deck when the boat is in the water, and for shocks and shakes that she will receive when in use. A rigid, tightly-bonded covering will be unable to resist the stresses that cause the decking to move, and will tear. This problem is common with sheathed laid decks, but a fabric glued to a well-fitted plywood deck will normally be satisfactory, until the time comes to replace the deck covering.

4 A paint finish which consists of numerous layers of assorted paints will crack.

Indiscriminate use of hard marine paints will leach out the oils from the paint and from the canvas waterproofing, leaving a wrinkled, dry, fissured finish. Apart from the cracks caused in the leaching and drying of the top coat, the finish will be further crazed by engine vibration and temperature variations.

5 Water which seeps between the fabric and the deck will cause rot - which will degrade both the covering and the deck planking. Decayed covering will tear up when pressed or stretched.

Fitting a canvas deck covering

The methods used to hold down and seal the edges of the canvas are tricky. The canvas is bedded in thick wet paint and tacked in place. The raw edge of the canvas is concealed by a batten or moulding which should be fastened so,that they can be re-used when the canvas is replaced.

When there is a nailed edge protected by moulding and the canvas is held by batten set in compound, the following preparation is needed.
Remove all deck fittings that can be unscrewed or unbolted.

Plank fastenings must be countersunk or punched below the level of the deck, and stopped with filler. Smooth and sand the deck. Shave down the high spots, and fill the hollows with commercial filler, or with epoxy resin mixed with fine sawdust. Seams between planks should be caulked and payed, or filled level with a flexible compound. Paint the deck with a priming paint, followed by an oil-based undercoat.

When the canvas deck covering is carried beneath cabin sides, canvas used for deck coverings should be 10 oz (280 g) weight. Lighter canvas will not withstand rough usage, and a canvas deck with exposed covering board when heavier grade is difficult to stretch and lay flat.