Saturday, May 1, 2010

Keel Questions

The keel on Atkin's Valgerda may be the most controversial element in his design catalog. Yesterday I received an email from Tom in Georgia, who is about to order Valgerda plans, but needs shallower draft than the 18 inches drawn by Atkin. Here's part of my reply:

"I looked at the Atkin keel and decided to go with a little deeper version of what a traditional faering would have. Faerings, according to Atkin's own account, had a 4-inch keel that ran the length of the boat. I deepened that to 6 1/2 inches and included about 100 pounds of ballast. Without any keel at all the boat draws 6 inches, so I figure mine will draw about 12 1/2 inches. It also looks better to my mind than the Atkin keel. No doubt his would go to windward better, but not much better, I'll bet. The decrease in the wetted surface should improve performance under oars and all points of sail other than hard on the wind. That's my justification. For more on my thinking on the keel look at this post and the two that follow it. You can also look at Rick Nardone's excellent build at and the comments following it.

"I did think about a centerboard, but not for too long. In the second issue of Boat Design Quarterly O'Brian talks about a Valgerda that he rowed and said it was a fine boat "except the builder ruined it by giving it a centerboard." I understand your need for shallow draft, but not having a centerboard opens up the inside of the boat in a wonderful way. I think it weakens the boat to have a centerboard and the board is always a maintenance problem and the case usually ends up leaking. That said, I'd love to see a Valgerda with a centerboard. I bet, with a proper foil, it would go to windward better than the original design. But, I think what we are taking about here is a full redesign.

"If I wanted a boat like Valgerda, but with a centerboard, I think I would build a Ness Yawl. They are beautiful boats and designed with a centerboard and kick-up rudder. Check out the voyage of my friend Giacomo from London to Istanbul in a Ness Yawl"

Rick Nardone and I have discussed this as well. His solution (unless he sells his boat and the new owner wants something different) is to go with a 4-inch deep keel like the original faerings had, but include the lead ballast into the keel. Since Atkin's lines are true to the original faerings it will need some ballast. Workboat designs need additional ballast because they were designed to carry cargo. I much prefer to have my ballast built into the keel than have it loose in the bilge. Having it in the keel means more room in the boat and less danger of loose lead damaging the boat or the crew in a knockdown. Having the lead lower means better righting moment too.

Valgerda's keel was a hot topic on the Wooden Boat Forum. The thread started in January 2001 and went on until late 2005. ( I'don't think you could go wrong building the keel according to the design. I also think the Vikings knew a thing or two about boats. Whether my solution is a good one or not remains to be seen.