Angus, I’ve noticed that you favor tumblehome in your designs. Could you tell us what advantage you see in it?

Thanks…Bill H

OK – take a very deep breath.


  1. A Footy has low stability and very low roll inertia. It is therefore by definition a ‘twitchy’ boat to sail. Long experience of offshore racing boats (think of the dark and rainy night) suggests that boats that perform 90% of 95% of perfect most of the time win more races than boats that perform 80% of 100% perfect. The problem is compounded by the fact that with a model you have far less feedback about how the boat is sailing than full size.
  2. A ‘traditional’ Footy is never going to plane. There is no reason whatsoever for the ‘dinghy like hull’. That works well at displacement length ratios of 200 and less (200 g. displacement on a Footy). But on a 500 g odd hull, we are looking at the behaviour of a steam-roller.
  3. Because of our inferior perception of what is actually going on (eyes only on a small object a fair way away), we are never going to have ‘instantaneous’ reactions by the helmsman to every puff.

Given this we need a hull that does two things

  1. Does not have a steep curve of drag against heel: i.e. a puff that makes the boat heel over on its ear must not increase its resistance very much. Ideally its speed will increase in a puff, not decrease.
  2. Remains truly directionally stable as the wind speed varies. I have heard claims for a number of Footy designs that they will sail ‘hands off’. I strongly suspect that this means keeping a steady net course +/- over a moderate period of time. True directional stability means that the boat will sail herself to windward PERFECTLY without a helmsman. This is attainable. Any decent Metre boat will do it. The S&S Swan 36 of the early ‘70s would do it perfectly.

Achieving (1) means that we must maintain the full waterline length as the boat heels rather than rolling the ends (particularly the stern) out. Reducing the waterline beam with heel helps reduce heeled drag. For obvious reasons, tumblehome reduces roll out.

(2) is closely related. We must not trim head down with heel (or no more than we can avoid). This generally means a narrowish stern and a fullish bow. It is easier to get the volumes right with a fair hull shape if we go along with tumblehome amidships. This is not easy to explain, but if you try drafting a hull of this type you will very quickly see what I mean.

Please note that with Footys (overall length rule) this applies only with relatively fat, heavy boats. The much lighter, narrower Freedom and Prometheus designs that are about to escape from the drawing board have slight flair throughout.

Thanks Angus…well articulated and understandable. Your point about midship volumes on wider boats is well taken. I may play around with the tumblehome thing a bit more myself. I’ve used it on a couple of Stollery-inspired designs, but not in a really thoughtful way.

BTW, I have achieved a state of tune on my Razor and American Footy that will sail hands-off to windward for long enough that my Footy is farther away than my comfort level. They hunt the wind, occasionally luffing slightly, then bearing away slightly to continue. Admittedly, this is in reasonable wind conditions…it doesn’t work in reallly gusty winds. So it might not yet be perfect, but it’s pretty darn good.

Bill H

One thing I probably should have added.

Quite apart from the fact that I think a Footy should essentially sail like a vane-steered or totally free sailng boat, I have a reason for being careful about lift out of the stern. The ‘Mariner’ type immersed transom is probably a tetchy brute. If we’ve got it right in a particular design, I don’t want to complicate matters by roll-out or head trim. if we’ve got it wrong, we’ve got it wrong!