Jason Ker

It's a recess to hide the flanged head of the keel, in itself it serves no structural purpose. Approx. 65mm deep. 'socket' usually refers to a structural connectIon, like a socket for a flag pole.

Actually no, sorry to be pedantic but all the evidence says the keel separated from itself. Rob woke hearing a metallic ‘Ping’ just before he was thrown across the boat from his windward bunk as they capsized. While they made their plans to escape it was apparent to Rob that the inverted boat was holding air pressure in the hull, so the top plate of the keel can only have remained fully bolted to the yacht. When the crew swam down out of the boat, they saw that the vertical part of the keel was missing, revealing that the keel had failed at the welded joint between the exposed verti

More like that.

Quite right, it was definitely a mistake for me not to re-iterate above that we didn't design the keel which broke!

1. What we know is that the hull was airtight upside down, so therefore the keel top plate was still there In its recess held on by 12 bolts... 2. We also know there wasn't any remaining keel vertical spar visible when the boat was upside down. 3. We also know the keel was built with a weld connecting the top plate to the vertical spar, so because of 1. And 2. we know the keel failed at the weld. Do we need to know anything else?

Thanks for your advice, just pointing out on here as the person with their name on the boat that the part not designed by us is apparently in two pieces, one still attached by a load of bolts to the boat and the other at the bottom of the sea. As a very experienced designer of keels, I've also pointed out here the likely failure sequence of the keel we didn't design, based on the information received about its construction.

Based on the information we have, it seems almost certain that the keel's top plate, which would be a ~35mm thick steel plate siting sub-flush to the hull, remains bolted to the boat with its 12 bolts. it would therefore be misleading to say (as some have) that the keel ( which we didn't design) detached from the boat, when almost certainly it 'detached' from itself.

Most of the original mass was there so we could tick the 'Solid Iron' box on the IRC form, back when that was important. Welds in tension are risky, you certainly wouldn't get an airplane certified that had its wings held on that way...

The material would have been much stronger than the original cast material, and being hollow is very efficient,, but the devil is in the detail, specifically the welded connection between the vertical hollow spar and the horizontal top plate, which is part of the keel I hasten to add, though it sits in a recess in the hull.

From afr.com: "It's undamaged other than the keel, I reckon.....Mr Buchanan said." Excuse me for re-posting here what I've already posted on the other thread my professional view of by far the most likely series of events in relation to the loss of the keel we did not design:. I would assume, based on the very limited information, that after a tension failure in the windward keel side plate welds, the leeward plate welds would have gone into bending, putting the I beam Internal longitudinal beam into torsion (certainly not a loadscase they are intended for) and after a short w

Correct

We quote consistent fees for keel designs, which we think represents the work required, including extensive FEA with NX Nastran. The owner of a second hand boat Is free to make his choice to use us or go elsewhere

As far as I'm aware this was the only example of a Ker design with a keel not designed by us. Allegedly we were overpriced.

Certainly when someone modifies our design without our involvement it ceases to be our problem technically, but it remains important to make sure people are aware of that as our name is in on the boat. Put simply 100% of our keel designs have remained attached to their boats, 100% of keels designed by others for our boats have not.

Wow... Huge typo never knew that was out there, will ask them to correct it, thanks for pointing out.