Hanging the rudder

With the new mahogany sternpost installed, it was time to rehang the rudder. This involved more earthmoving than you might initially think.

Digging the hole

The rudder drops out the bottom of the boat. There’s no other way. The rudder and attached post tube slides down through the hole in the aftertimber and exits below the hull. The problem is that when the boat is sitting on blocks, there isn’t nearly enough clearance underneath to pull the assembly clear. So we dug a hole.

Hole dug beneath the stern of the boat with the rudder dropping down into it — The hole.

Drilling the hole for the rudder post

The trickiest part of the whole operation was drilling the hole through the aftertimber for the rudder post to pass through. Get this wrong and the rudder hangs crooked, which means the boat won’t steer straight, leaks, or both. It’s one of those things that you want to get right the first time.

We used a jig clamped to the sternpost to guide the drill. Ideally you’d use a barefoot auger for a job like this — an auger bit without the pilot screw - so it doesn’t pull itself through the wood and follow any weaknesses or irregularities in the grain. We used what we had, and the hole was only a few inches. You really want a barefoot auger for long holes that need to be dead straight, like for a prop shaft.

Person using a drilling jig clamped to the sternpost to bore the rudder port hole — The drilling jig clamped to the sternpost. The wooden blocks guide the bit to keep the bore straight and true.

View from below the hull showing the drilled rudder port hole through the sternpost — The finished rudder post hole from below.

View from inside the boat looking down at the rudder post strap through the frames — Rudder post hole. And some nice looking new planking!

Close-up of the rudder post bolt and washer from inside the boat — Another view of the hole.

A new copper strap

The rudder post is held against the sternpost in three places. First, where it goes through the hole in the aftertimber, there’s a flange bearing. It’s held by a bronze gudgeon at the very bottom. And lastly at the midpoint by a strap — a piece of metal that wraps around the rudder post and fastens to the sternpost to keep the rudder from wandering. The original strap was, to put it charitably, undersized.

The original rudder post strap, a thin piece of metal resembling plumber's tape — The original strap. This is what was holding the rudder post in place — a piece of metal that looks like it came off a plumbing job. Does not inspire confidence.

We made a new one from copper plate. Copper is an acceptable material here — it’s compatible with the bronze rudder post in terms of avoiding galvanic corrosion in salt water. Importantly, it was easily available, soft enough to form, easy to work, and stiff enough to hold the rudder in place.

Copper rod bent into a U-shape on the workbench — The raw copper stock, bent to shape around the rudder post diameter.

Finished copper strap with countersunk screw holes — The finished strap, drilled and countersunk. Three fastener holes on each side to spread the load across the sternpost and deadwood.

With the new sternpost already in place, we could now hang the rudder. After much searching, we found an off-the-shelf bronze gudgeon for the bottom bearing. One of those rare cases where a production fitting matched what we needed.

Stern view showing the new mahogany sternpost with rudder hung and fairing in progress — Dry fit from the starboard side.

Rudder hung on the sternpost, viewed from above showing alignment — The rudder fully hung from port. Initial shaping of the sternpost is visible. Eventually we will fill and fair the rudder foil itself.

Person standing back to inspect the hung rudder and stern from a distance — Nice.