Hi All,

After viewing Ross's post showing his work on his retractable skeg [nice job Ross] I thought I would raise a question on skeg design...

The retractable skegs that I have seen are relatively narrow and project quite a ways below the hull. This "penknife" style would result in substantial leverage being applied to a small support area at the pivot point by normal forces on the skeg. Contacting the bottom while moving forward would apply a large force to retract the skeg [probably not a problem] but a sideways or reverse direction force has the potential to do structural damage.

My initial [half-baked] thoughts on a retractable skeg would make it a low profile that it did not protrude far below the hull line - 3 or 4 inches max; it would have a full radius on the leading and the trailing edge so that would not "catch" on anything when backing up. The blade would be long enough to have the required surface area and it would be fully supported over the whole length by the slot in the hull. The skeg box can be a lower profile and fit more out of the way further back in the hull.

The other thing I am going to look at is using rare-earth magnets to "connect" the skeg to the actuator lever. The idea being that I do not have to deal with a hole thought the bulkhead [that may leak] to run a cable and I could "attach" a magnet anywhere on the blade which is not possible with a cable. The other benefit is that If I did hit a solid object with the skeg that the magnetic field would just "shear". Operating the control would re-engage the magnets. I have been playing with a few different sizes of those magnets from Lee Valley - you can't imagine how strong they are until you try to separate a pair of the 1 inch ones. I have been using them to clamp scarf joints - they will easily "couple" through 1/2 inch of wood.

After paddling Greg's Guillemot with it's retractable skeg I am definitely going to be building one into my Guillemot. I see it like a trim tab on an airplane - you can live without one but then why would you want to?

Any comments/suggestions on this kind of design??

Thanks,

Hank