Wednesday, 23 May 2012

Rudder and tiller

Whilst waiting for epoxy to set on the tender at times I started on parts for the Sundowner.  I had ordered the plans from John Welsford after exchanging emails and discussing stretching it a little from 21 feet 4 inches to 23 feet 8 inches (12%).

Once the plans arrived and wood obtained (Lazarides timber in Brisbane) I firstly started on the rudder and tiller which looked like something I could handle.

First off was sixteen lengths of 40mm x 40mm timber with a maximum length of 1880mm.  As you can see below the first four were hardwood for strength followed by 12 of medium weight softwood of decreasing length.  Just up from the base, and at 400mm/800mm above is a horizontal 6mm 316 stainless threaded rod with nuts and washers on each end.  The initial locations were drilled with a drill press to ensure they were horizontal, then I carried the holes through with a cordless drill.  As I drilled each one, I used it as a template for the next.  While I was concerned about the final hole being off centre it worked fine.

The picture below shows the rudder epoxied and bolted up.

Once the epoxy was dry I took the rudder and shaped the profile using the scale drawing supplied with the plans by JW.  If you look carefully on the rudder, in particular the right because of the colour of the wood, you can see the spaces where the nuts are located on the threaded rod.  Once shaped thickened epoxy was used to fill the holes to match the surrounding shaped rudder.  I started gently cutting pieces of waste off after marking the profile on the bottom of the rudder, but was making more of a mess than anything.  Out came the electric plane and shaping went well after that.  Very small amounts off at a time, then final sand.  There was one area where I cut too much off prior to getting the plane out, which was filled with epoxy by levelling the surface on saw horses and pouring it into the hollow.

To reinforce the rudder, each side of the top is also covered in a 20mm thick support from Australian hardwood with epoxy and screws.  Prior to fitting I cut the hole for the removable tiller to fit in, lesson learnt from the tender build where I forgot to cut the recess prior to putting on the outside supports (realised on my way to work when congratulating myself on how well the tender rudder epoxy went).  On the right you can see the tiller made from two pieces of shaped hardwood lap joined with stainless screws and epoxy.  I used joined pieces to reduce the waste due to the curve, and there was no noticeable decrease in strength.

Close up of hardwood supports and tiller recess

Below you can see the 9mm plywood baseplate and the 50mm centre holes for attachment to the bottom with 14 guage (I think) 316 stainless countersunk self tapping screws.

This is the final result with the screw holes filled with epoxy.  If you look you can see the baseplate has a fillet of epoxy between the ply and the vertical wood.  Another benefit of making the tender, my fillets are getting better with practice.  Bottom right is a claw hammer which gives you an idea of the size of the rudder.  It is taller than me, and runs full length of the transom from the base of the keel to the top of the cockpit cover.  (Please excuse the boating terms, still learning them and I think I have that right)

Another angle closer to the bottom, note the shape at the top of the softer wood to allow attachment of a rope in case of rudder issues.

Side on view of the tiller showing the curve, and right hand end which fits into the rudder.

Final result below waiting for down the track.  Entire rudder has been coated in two coats of epoxy, then I got carried away and put two coats of epoxy two-pack undercoat and sealer on.  I need to do a bit of sanding on the tiller hardwood to get it to fit into the recess.  I epoxied the recess figuring it would be easier to repair/replace the tiller (maybe a nice laminated one with different layers of dark hardwood and pale softwood like Charlie Wipple's on the JW website) than to repair the rudder from water damage.

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