Episode 24 Keel locking pin

I don't like stuff that doesn't work. The locking pin for my keel had been annoying me for some time. Its not that it did not work, but that it did not work well.

My Austral 20 has a swing keel, which pivots on a pin near the front of the keel box. I had quite an adventure un-jamming the keel, and now it swings up and down freely.

The locking pin is a big bronze rod that locks the keel in the "down" position. It is located just aft of the keel, and is inserted into a hole in the side of the keel box, when the keel is down. Theoretically, the keel is heavy enough to stay down, but there is always the worry that if the boat gets rolled more than 90 degrees, the keel could swing up, changing the centre of gravity in the boat and resulting in a full upside-down-and-can't get-upright-again experience, which is something I'd prefer to avoid.

I had noticed that I could not screw the locking pin in. Also, when I grounded the keel (gently) it bent the pin backwards by tearing out the mounting screws. The problem, I deduced, was that the socket on the far side of the keel box was misaligned or blocked. The only solution was to disassemble the locking pin assembly. This was easier said than done because of the odd assortment of corroded screws, epoxy filler and plastic mounting plates that had accrued over the years following the attentions of previous owners.

The application of a drill, hammer, old chisel, much banging and bad language eventually got the components free. These are shown in the photo below, and comprise

• The brass pin (1/2" diameter)
• A brass ferrule on the near side, into which the pin was inserted (1" outside socket)
• A brass socket on the far side, in which the end of the pin rests (1" outside socket)
• A brass blank, to cover the hole when the keel was up, and so stop water from slopping into the cabin through the open hole.
• Assorted brass and stainless steel mounting screws, most of which were totally destroyed upon extraction

Austral 20 keel locking pin components

When I got the bronze components out, I cleaned them up with wire wool. They came up like shiny old coins, as illustrated below.

Austral 20 brass ferrule and socket for keel locking pin, before and after  cleaning with wire wool

The original design had a clever feature. The head of the pin had an indented centre, and the blank had an embossed or raised centre; one for "in" and the other for "out", so you didn't need to remove either to check if the pin was in or out.

However, the weakness was that the screw holes in the ferrule and socket were too close to the centre,  and could be easily ripped out.

My suspicions were confirmed when I finally got the socket out and found that it had been filled with putty and then epoxied over. I have no idea why, except maybe to stop a tiny drip from getting into the cabin. The result meant that the pin could not engage the socket, so it was only held on one side. Any forward force applied to the keel would push the pin backwards and, because it was only held by three screws in weak screw-holes, would rip the ferrule off its mounting, making a horrid mess of the GRP and balsa core sides to the keel box.

My solution was to make up a couple of stainless steel plates, 100 x 100mm, to reinforce the mounts, and to provide a waterproof seal (like the plates I had made for the keel pin).  The hardest part was drilling the 1" diameter holes for the ferrule and socket, because the biggest metal drill bit I had was half the required diameter. Being unwilling to spend large amounts of money for a full sized 25mm metal drill bit, I decided to stitch-drill a ring of smaller holes around the diameter, and then file then out the remainder with my needle files. This was tedious, but eventually gave me the holes I needed.

The completed assembly is shown below. I have yet to fit it to the keelbox because I need to have the keel down to get everything aligned. Getting the keel down is easiest to do when the boat is in the water, which means I will have to relaunch the boat, which should happen next weekend.

And, yes, the holes for the locking pin are above the water line. (Think about what would happen if they weren't.)

Austral 20 locking pin assembly with stainless steel plates added. The stainless steel plates will be mounted either side of the keel box.