Swimming in Rudders

As of this moment, there are 6 different mock-ups of the rudder-to-be out in the shed- the original pattern, the new master template, two screw-ups, and two which will hopefully end up being the completed “practice” rudder. If you are curious and need a rudder refresher, here, here, here, here.

These are the two screw-ups, I messed up some math and they’re 1/2″ off

I’m building the “practice” rudder out of cheap 3/8″ plywood, once I verify everything fits where it’s supposed to, I’ll make the real thing out of marine grade plywood. Marine Ply runs $80-100 per sheet, so I’m happy to butcher some sub-floor until I get it right.

I started with the tracing of the original rudder. The tracing includes the bronze rudder post, so I offset the master template by 1/2″ (the radius of the rudder post) + 1/8″ (the difference between the radius of the router bit and the thickness of the plywood…this took a while to figure out) for a total offset of 5/8″. Part of the reason I’m going into this much detail is so I can remember WTF I did when it comes time for the real thing.

Probably the trickiest bit was matching the curved bit of the rudder stock. I made a jig to guide the router, which I’m using to shape the edge of the plywood to sit flush against the curved surface of the rudder post. What I didn’t remember was something I probably learned in high-school geometry about translating curves or tessellations or some such thing. I initially kept the jig in line with the edge of the plywood, but that ended up shifting the curve down when I routed the edge…a bit hard to describe but I was able to get it close enough like so:

Once I figured out how to line everything up, the routing went very quickly.

The next step is to route out the grooves for the bolts which attach the rudder to the rudder post, tack everything together and see if it fits on the boat! Hopefully I won’t have to add to my collection of rudders.

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2 thoughts on “Swimming in Rudders

  1. Pingback: The Moment of Truth | The Bonnie Boat

  2. Pingback: Miscellany | The Bonnie Boat

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