Friday, August 18, 2017

Rudder Redo

The rudders on Little Cat were having a hard time. They had performed for eight years without a problem, but were looking beat up. They were also flexing a lot at the head of the rudders where they articulate with the tillers. Although built to plan (unglassed 5/8 plywood), clearly some additional stiffness was required. So, after the hull refit in Summer 2016, the rudders came off for an overhaul. The job required a substantial clean up of the unglassed wood, application of an all-over layer of 6oz glass, and a repaint with plenty of coats.

Encapsulation with 6 oz glass cloth.

The wood cleanup took time. First paint strippers were used to expose the wood. Some water had got under the original epoxy barrier coat in places and the damaged wood had to be gouged out and filled with thickened epoxy. After further sanding and prep, 6 oz glass was laid up with West 205 epoxy, and then followed by two further fill coats.

Reinforcing the rudder bottoms with layers of glass.

Because Little Cat sits on a drying mooring, I wanted extra protection for the bottoms of the rudders, so two extra layers of 6 oz glass were added, and I made sure that there was plenty of glass and epoxy around the vulnerable "front" corner below the bottom hinge.

Finished bottom corner. Filling behind the hinges with epoxy.

The rudders on Little Cat each have three sturdy handmade stainless hinges. These are a departure from the Wharram plans which specify lashings, but I like them as it is easy to remove the rudders to keep up with maintenance. Like any metal in wood, though, they are a PITA to maintain and are inclined to bleed rust stains. I should have removed them for the refit, but ended up treating them with West 650 epoxy coatings in place, and also filled the cavities between hinge and rudder with epoxy.

Another view. Lots of sanding and filling to go.

After all of the epoxy had set, I painted the rudders with two coats of Interlux undercoat, and a single coat of Interlux Brightsides topcoat and put them back on the boat. I went for the sail described above to Half Moon Bay to check if the single layer of 6 oz glass gave the rudders sufficient stiffness, or whether a second layer was required. The rudders seem just right with a single layer - there is a little bit of flex remaining, but the head is now plenty stiff. Adding a second layer would add little but weight. The last job was to get in the water and mark up the water line on the rudders for the antifouling.

Three coats of Interlux Brightsides top coat. Yes, I am proud of my roll and tip technique.

So, the rudders came off again for a further two coats of Interlux Brightsides topcoat.

Three coats of hard antifouling paint.

The last job was three coats of Interlux Fiberglass Bottomkote antifouling below the waterline. The final tally was a layer of 6 oz glass cloth, three coats of epoxy, two coats of primer, and three coats of topcoat (above the water line). It was a lot of work, but now the rudders are stiff, fully protected from water intrusion, and should be looking good for several seasons of sailing.

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