The grindhouse rules, powering the AC75 with Harken


In the 36th edition of the America’s Cup, the role of the grinder is more important than ever before. AC75 class boats are powered by both human energy and battery power. Whilst the batteries control the main foils and rudders, everything above the waterline, including every sail control, is powered by the onboard grinders using pedestals supplied by official Winch Systems and Deck Hardware partner, Harken.

Needless to say, the more power generated, the more accurately both the mainsail and headsail can be trimmed. That is why on INEOS TEAM UK’s AC75 ‘Britannia’ there will always be eight or nine people turning the handles on the Harken grinder pedestals and generating power for the trimmers. One of those grinders is British/Australian Graeme Spence, now in his second America’s Cup campaign (he sailed with ORACLE TEAM USA in the 35th America’s Cup in Bermuda).

INEOS TEAM UK grinder Graeme Spence
© Credit Lloyd Images / Mark Lloyd

From the outside looking in, the role of a grinder may appear to be a relatively simple one. Simply gain as much strength as you can to enable you to turn the Harken grinding handles and generate as much power as you can come race day. For Graeme and for the other grinders in the team, however, it is much more than that.


“For the Grinders staying fit and healthy is a big priority. During long sailing days we need to rotate Grinders on and off the boat regularly. We have enough sailors to enable us to do this, but it’s important that everyone is fit and able to sail all the time. We can’t afford to lose quality time on the water because guys are tired or injured”.

“There are some positions on the boat that trim sails whilst grinding. This is different to most other yachts, where trimmers can spend time with a sheet in hand, looking at a sail and making little adjustments. For us, the most important thing is putting the power down and making sure the sails are trimmed correctly without fiddling too much”.

It is not just about generating as much power as possible at any given time either. The work each grinder does on the boat is closely monitored and measured so that the power can be generated in an as efficient way as possible, ensuring the boat reaches its top speed for the given conditions.

“We measure and record pretty much everything on the boat, data analysis is a big part of the America’s Cup. Teams are looking for a human performance advantage so it makes sense that we would be monitoring the athletes as closely as we are the yachts. We look at heart rates, or power generated at the handles, then look at how we can link up that relative effort with where it’s most efficient for making the boat go faster. Anyone can wail on a set of handles, but we need to be smart about where and when that power is used.”


Grinders views onboard INEOS TEAM UK's AC75 'Britannia'

There is only so much time a grinder can spend in the gym or on the water too. Their role within the team is a wide-ranging one and one that sees them work closely with the design team particularly.

“As part of the sailing team we don’t just turn up the first day the boat goes into the water. The way I see it is we are the end users of a very specific product that has been built for us to race and win. Whilst we may not always have the best theoretical knowledge in the team we do have a unique set of experiences that is essential to the yachts design. It’s no different than building your dream kitchen, you are the end user and you need to pay attention to each step of the design and build process. Ultimately everyone needs to share their knowledge to come up with the best possible product.”


Engineering Technician, Nic Wellspring working on a pedestal modification

One of the areas in which all of INEOS TEAM UK’s grinders have a significant amount of input is the design of the grinding pedestals and handles themselves. Whilst manufactured by Harken, Graeme and the team’s grinders spend a huge amount of time, both in the gym and on the water, grinding and testing different options for handle grips and grinding pedestal geometry.

“It’s an interesting one because grinding as an athletic sport is really in its infancy”, said Graeme, “I think there are gains to be made by exploring new things, particularly from other sports. We have been through loads of stuff, I was massive proponent of American Football gloves for a while, but I ended up coming back to just bare hands. We try different things, but I’m only going to mention the ones that didn’t work.”


INEOS TEAM UK grinders Neil Hunter and David Carr working on the Harken drive train

It doesn’t stop at optimizing the equipment. America’s Cup grinders have a massive impact on the deck layout itself. Because they provide such an important energy source for the AC75, it’s mission-critical to maximize efficiency in the cockpit areas. They spend a lot of time there. Pin-point precision goes into creating an ergonomic cockpit, a task that Graeme and the team take very seriously.

“The sailors have a lot of input into their positions and they are always developing. For both our boats we have built life-size cockpit models. The wooden cockpits were regularly updated as we receive new drawings from the designers. These models are vital tools, a sailor can jump into the cockpit were they will sail and make sure they can reach and operate everything. If someone needs to be able to cross the boat we can test how they will get in and out of the cockpits. This is important and its done over many hours of chopping and changing the model in the boat shed”.

“Luckily compared to the Catamarans of the last Cup, this time round the cockpits are much better for the grinders. The Catamarans were smaller so we had to spend a lot of time grinding on our knees. Kneeling is a less powerful grinding position, but it kept us out of the wind improving aerodynamics. Now the cockpits are a lot deeper so we can stand up in a preferred grinding position and remain out of the wind”.

“The development from the first boat to the second boat has been interesting. For the first boat we had a limited amount of time from receiving the rule to starting the build. The emphasis was on speed of build and getting on the water as quick as possible. The second boat has evolved from our learnings on boat one, but also from observing the design directions other teams have taken.”


INEOS TEAM UK, skippered by Sir Ben Ainslie, training on their race yacht ‘Britannia'
© Lloyd Images

The cockpits are not just built for performance either. Another hugely important element that must always be kept in mind is safety. The AC75 class rule stipulates, for example, that the cockpits must be self-draining and must be able to drain out a set amount of water in a set amount of time.

“That’s just one of the creative challenges associated with the America’s Cup”, said Graeme. “You are trying to design a boat that’s fast, but it obviously needs to have some safety requirements. One of those requirements is always going to be that it doesn’t sink! Without the drainage rules, there could be performance gains. For example, you could fill your cockpits up with water to gain boat speed from the increased righting moment. The rules stop that.”


Ultimately, it’s clear that the role of a grinder is in an America’s Cup team is a hugely important one. Whether it’s generating significant amounts of power through turning handles and keeping as fit as possible or working with the design team to optimise the grinding pedestals and deck layout, there is always something to do. Even when there isn’t anything immediately pressing for Graeme to take action on, he will make sure he can find a way to help win the Cup.

“Working in such a varied role gives you the unique opportunity to be able to muck in and help out different parts of the organisation. If the sailmakers have a lot on, for example, and they’ve got a bit of tidying up to do, it’s much better for the team that you help them out. There are going to be times when you get off the water, debrief, then go home to rest, whilst others stay late into the night to prepare for tomorrow. Part of being an America’s Cup sailor is helping out when you can in the hope that it makes up for the times you can’t."