America's Cup - Softbank Team Japan explains why watts matter

by Softbank Team Japan on 12 May 2017 Four years ago at the 34th America’s Cup in San Francisco, Ryan West, then a trainer for Oracle Team USA, watched the finals and knew that the discipline of grinding – specifically the type of power produced – had markedly changed.

Compared with traditional sailing, the power output necessary to provide the hydraulic pressure to control the dozens of systems onboard the yacht had increased exponentially.

Now he’s more than two years into his role as Athletic Performance Director for SoftBank Team Japan, and has overseen the development athletes that have pushed past all the metrics of what was possible physically from the last Cup.

“From conception, everyone recognized at the last America’s Cup the new level of physical fitness you would need to be competitive in the 35th America’s Cup”, said West. “Over the course of the campaign the training team has tested and learned alongside the systems team.”

That relationship with the design team has been critical in how SoftBank Team Japan has approached the issue of power output – pairing the gains on the grinding machines with a proprietary control system designed to maximize the efficiency of how the power is used.

“These are thirsty but efficient boats. In the early days we saw systems where the work onboard was hard and intense, now, as the systems have become more refined we’re becoming more efficient with energy put into the boat – from the handles to our systems to usable energy output.

“That link and how refined it is and its efficiency, that’s where the real gains are being made.”

And it’s that relationship that has kept SoftBank Team Japan designers and boat builders up late at night as they explored the theory that highly efficient power transfer would be a key decider in the upcoming America’s Cup.

“They’re all hydraulically powered, but these boats are much closer to airplanes than tractors“, said Glenn Craig, Hydraulic Engineer for SoftBank Team Japan.



“It’s all been about eliminating compliance – making the hydraulics as efficient as possible. Low friction seals, custom Parker manifolds, even taking the time to measure and install hard tubing that’s custom fitted down to the millimeter – these are all areas we’ve been focused on since day one.”

“Watching the other teams on the water, we’ve seen that there’s a difference between how much importance teams have put in this area. If a team thinks they can create lots of power, then they wouldn’t have paid as much attention to its efficiency.”

Yet sustained levels of high-power output has always been the goal and lately, West says the traditional metrics for measuring the amount of wattage generated by arm power have been shattered to the point that the book is being rewritten.

“The wattage we’re seeing is extremely high for arm power – much more than you would see in literature on tests using arm power,” said West.

“These guys are extremely specialized athletes in a sport with no comparisons where you’re putting out such high amounts of aerobic power for 20 minutes.



Their arm output now has reached into the realm of wattage output traditionally reserved for cyclists.

“Judging based on what we’ve seen in the gym and testing, there has conservatively been a 20-30% increase in wattage over what we were producing in San Francisco.”

Crucial to these numbers is the crucible exercise that every SoftBank Team Japan sailor has a love hate relationship with – the grinding test.

Initially developed by West during the 34th America’s Cup to measure the athleticism of sailors in the power hungry AC 72s, it has since become the team's benchmark test for grading performance milestones.

“The grinding test. It’s essentially a graded exercise test in which they grind at a certain resistance for a minute forward and a minute back and keep ratcheting it up until they can go no more.

“The hardest part about the test is mental – there is no end point so you have to push it – you find out their ‘true’ max. The levels they’ve reached are significantly higher than ever before.”

“Last time with the evolution of the sport we never saw guys cross the original threshold of the test we were aiming for. This time we’ve had the majority of the team push significantly beyond that expectation.”

How far have SoftBank Team Japan grinders had to develop their aerobic ability to surpass this benchmark?

Take Grinder Yuki Kasatani for example. A former professional rower, Yuki joined the team in November of 2015 weighing 80kg. He has since put on 12kg and has improved his grinding test score by 63%.

Even more telling, veteran America’s Cup sailor, Derek Saward – whose scores were already high based on his previous Cup experience rooted in high-resistance grinding systems – has improved 31% since start of campaign.

Asked about whether there is any merit to the claim that leg-powered yachts might have an edge over arm-powered yachts, West was quick to point out that the gap has closed significantly.

“We see some advantages of cycling over grinding – there may be a slight edge to the production using cycling – but it’s not the gap that people think. It ultimately boils down to the entire system and how efficiently you’re using the power.

“We’re seeing a shift. In cycling a watt isn’t just a watt, it’s how you use it and when and it’s the same with the America’s Cup this time around. It’s not a wattage-to-wattage, it’s input to output. You could input different amounts of power into the system but teams that can more efficiently manage the output will win the race.”

“By the end of the Cup, I wouldn’t be surprised if we’re able to increase our output again by an additional 10% or more.”

For more from Softbank Team Japan click here