AC34: Atemis Racing Navigator Kevin Hall

Michelle Slade interviews Kevin Hall – the head of the Artemis performance-instrumentation team. This excerpt illuminates some of the complexities and tradeoffs associated with the ongoing hydrofoil experiments. There is no free lunch.

(…) You guys don’t seem to be putting much emphasis on foiling – what’s your thinking on that?
KH: I remember being in one of the very early design team meetings and one of the assignments for the performance team was to make sure we were on top of all the things we would want to measure, maybe occasionally have some sailor input. Adam (May) and I are both Moth sailors. At that meeting, [designer] Juan [Kuoyoumdjian] and his team came in and announced that it was clear that if you could get a boat foiling and going straight and fast, there was a little bit less drag so it went faster. We had that discussion a long time ago, but it’s correct. We’re not pursuing it to the same extent that the other teams have because there’s always been the question of control. It’s one thing to get something to fly in a model and it’s another to get it to fly in the real world. Hats off to ETNZ for doing that – really!

Then there are trade-offs after that. You pay a price for generating the lift to be able to fly—that price is the drag—then you pay another price for generating that lift in a way that also gives not active control like we have in the Moth but a form like that you can control as the height/lift/leeway changes. They’ve done a good job of making that fairly self-regulating. For us, we’re not sure that all those penalties are worth it. So while you’ll probably sure you’ll see our boat out of the water a bit, I’m not sure how much.

There’s rumor that foils may be abandoned because of the size of the course.
KH: Even on a really good day on a Moth, you do have to bear away and get up on the foils before get going fast. For that brief time you’re slower than a boat that’s designed to sail through the water traditionally. They may already have worked out that all those little times where you have to heat up after a jibe or bear away [after a tack], maybe that’s too costly. We can kind of tell a little bit what they’re doing when they’re going straight but it’s very hard to have a feel for all the dynamic stuff from faraway. Certainly they [ETNZ] know that.

So far Oracle, Emirates Team NZ and Prada have all been testing foiling. ETNZ has been testing for some time on the SL33 surrogate cats (very effective for learning!) The SL33 is another Morrelli & Melvin design: