Foiling through the Tack: Team SoftBank Japan Gets it First

America's Cup Challenger SoftBank Team Japan completed its first foiling tacks on its AC45, in May. Tactician Chris Draper gives us the exclusive on how they pulled it off.

Between appearances at America’s Cup World Series events — the next is Toulon, France, in September — it’s been all business for the Cup teams training in Bermuda and at their bases elsewhere. While their 50-footers for the real Cup show in 2017 take shape under the meticulous eyes of the build teams, AC45 training continues apace for the sailors, refining every maneuver down to the last nth-degree. It’s now widely known in Cup circles that a few of the teams have achieved the Holy Grail of foiling: the tack. Today, we checked in with SoftBank Team Japan’s Chris Draper, who confirms that they nailed their first foil-to-foil tacks back in May, were the first to do so, and are finally ready to talk about it.

What is the significance of the ability to foil through tacks?

From the perspective of the last America’s Cup and sailing foiling Moths, we’ve seen the progression of being able to sail downwind on the foil, to jibing, going upwind on the foil, and then tacking, which adds up to being able to do the entire race on the foil. The same evolution is happening. In the last Cup we designed the boats thinking we would be foiling downwind and that foiling upwind would be very tricky. Then Oracle kind of proved that wrong using foils that were essentially designed to go downwind. Now we have foils that can provide upwind and downwind foiling, so the next step is just keeping the boat on the foil the entire race. In training, the only time we were coming off the foils was when tacking, so that was obviously the immediate thing to solve.


What was the solution?

It’s the same with the foiling jibe in that it’s learning the technique. Emirates Team New Zealand lead the way with that last time around, so it’s great that Dean [Barker] is probably the first one to do a foiling tack, he having been the first person to probably do a foiling jibe in a boat of this kind. The solution has been about refining our technique and making sure we have the tools to do it. There’s a lot of stuff to align and get people into positions to make that happen.

How much of it is tied the efficiency of the hydraulics?


Having the energy to get the boards down and to sail the boat fast out of the maneuver is essential so there’s a lot going on. There’s an enormous amount of energy that has to be produced to drop a daggerboard and then lift a daggerboard and control the rake during the maneuver. There’s a big oil demand very quickly. The more energy efficient the boats become the better we will get.

When you completed your first foiling tacks in May, was it the result of a calculated progression or a surprise?

When we first started sailing the boat in Bermuda we saw that Oracle was getting really close already. So was Artemis. All of us who sailed in the last Cup knew that the tack would be the next thing we’d be doing and we had a couple of moments where we got close quite a while back and had flashes of what we had to do to make it happen. Then, one day we did two in one day. A bunch of us were laughing because it did happen quite effortlessly, as if we were tacking a Moth. We know that Oracle is doing them now as well because we sail with them. We were with them when we did our first ones. We know Artemis has done a few and I’m sure that the others are doing the same. There might be differences opinion as to who did them first [laughs].


How does the ability to foil tack change your playbook?

It will make for some pretty cool racing because it opens up the racecourse. The losses become a lot smaller in the tacks so our tactical options open up a lot. That’s what we saw last Cup: When ETNZ and Oracle were coming into the bottom gate, for example, it was quite hard to determine which gate they were going to because they were so good at jibing. You’ll see similar things like that with tacking, whereas the losses in tacks will be very, very small. Once, and if everyone’s doing them, the race essentially remains the same. In the pre-start it won’t be as significant, but it will open up the course. Bermuda is a really open course anyhow, where you can really make any side work if you pick the right nooks and crannies. So we’re working on the basis that everyone will be doing it and everyone will be really good at it.

Now that you know how to do them, how do make them better?


They’re getting more consistent, but it’s an evolution. We’re obviously watching how other teams are evolving with their techniques of sailing the boat—whether straight line, tacking or jibing. Different techniques will help others, so we’ll keep an eye on those.

What’s the step-by-step?

Fundamentally, it’s dropping one board, tacking the boat, lifting the other board and coming out still foiling. As I mentioned before, there’s a lot of energy required to get the daggerboard down, and then there’s the timing of the turn and the other things associated with getting the other board up, transferring the load across the boat. There’s a lot to get right to make it happen. There’s no one set way to deal with crew movements. Others do it differently, for example, I’m the first person to cross, but with Oracle, Tom [Slingsby] is the first person and he’s normally grinding.

How precise must the turn be?

We’re always within one or two button presses of it going pretty bad, so it’s important to get right. With the jibe and tack, especially with these boats, the maneuver is never really the same all the time — there’s always something that makes it different . . . a tiny lull or a tiny gust can change things significantly.

So, the million-dollar question: How much do you gain through a foiling tack?

I can’t give you any numbers on that . . . but remember back to the last Cup and the amount of distance someone gained in a foiling jibe over someone that didn’t . . . there’s plenty there. To put it in perspective, though, in an AC45, the World Series boats, we work on the basis that you’ll lose about four boatlengths in a tack, and that’s just going 15 knots into to the tack and going 15 out of the tack, so you can imagine what the advantages are of a foiling tack when we’re going twice as fast.