America's Cup- Nitro's Wingsail Trimming Primer

by Richard Gladwell. Sail-World.com on 14 Mar 2010
Sail-World's Richard Gladwell interviewed Noel (Nitro) Drennan, on the Sail-World stand at the Auckland International Boat Show.

For those who do not know Noel, he is a four time America's Cup campaigner (mostly with US based challengers) and is a Volvo Ocean race winner, as one of the crew aboard illbruck Challenge in the 2001/02 event.

A veteran of 25 Sydney Hobart races (the latest on Alfa Romeo), Drennan has just joined a very elite group who have won the Volvo Ocean Race and the America's Cup.

(He's called 'Nitro' after sailing on a Melbourne yacht, called Nitro, when he was young - and the name has stuck.)

Sail-World: Well done on winning the America's Cup, but where did you start with the Cup?

Drennan: I did my first America’s Cup with a small involvement with some of the Australian syndicates in the early 80s through North Sails, but my real start in the America’s Cup was with Stars and Stripes Dennis Conner in Auckland in 2000. I did my second America’s Cup with Stars and Stripes in 2003 and after that joined BMW Oracle.

Sail-World: What roles were you in when you were working with Dennis Conner?

Drennan: Initially with Dennis in ’99, I started looking after the whole sails program and coordinating the loft which was pretty interesting. I really enjoyed being part of the team with Dennis on it and Tom Whidden and some of the legends of sailing and America’s Cup sailing.

Sail-World: How did you start out in sailing? You were born in Ireland weren't you?

Drennan: I was born in Ireland in Dublin and moved to Australia with my family when I was 13 years old. I lived in Ireland long enough to know where the place i,s and what it’s like living there, and I’m living in Australia now.

My family sailed in Dublin and we sailed small dinghies, and when we moved to Australia we straight away started sailing in Melbourne, in small boats, and moved into bigger boats.

I started working at North Sails in Melbourne in 1983. Prior to that I’d worked at Hood Sails with Col Anderson in Melbourne; he showed me the ropes, and that was great.

Sail-World: What was it like to work with Dennis Conner?

Dennis was really good to sail with. He was just a wealth of knowledge, obviously, and I really enjoyed working for him because I did a lot of the Etchell sailing with him and we did a couple of Worlds together and a couple of regattas in New Zealand and Australia. He has a wealth of knowledge in the Etchells class as much as the America’s Cup.

After the 2003 Cup I spoke with some of the Oracle guys and we did the Moway Cup in San Fransisco in late 2003; that was basically when I started, with BMW Oracle.

Sail-World: When did you stop sail-making and concentrate fulltime on crewing?

The whole time while you’re looking after sails, you have to be sailing on the boat as well to really be part of it, so it’s the only way to be fully tuned in rather than just somebody telling you what’s going on all the time.

Being a sail-trimmer is just a continuation of normal sail making life, in a way, where you’re sailing and working on the sails and trying to improve both areas.

Good sail trimmers in general have had a background in sail making, and it’s a similar situation across all the teams - that most of the sail trimmers have had a pretty solid sail making background. Some of it might have been a long time ago but when you have all the basics there of the sail making it enhances your sail trimming ability while you’re racing.

Sail-World: At what point did you sign up with BMW Oracle?

In, 2003 for the 2007 Cup and the entire trimaran lead up and obviously the 2010 Cup.

It was a long lead up to the 2007 campaign.

Sail-World: What initially happened when the Deed of Gift Challenge became a reality. What did you do with sails - what it a blank piece of paper exercise?

Drennan: Initially we signed up to do a monohull challenge. But when the Deed of Gift challenge became a reality we all looked around at each other and went ‘ooh’. Not many of us had sailed catamarans. A few of us went out and bought A-Class catamarans straight away and that was a really good thing to do. We did several other classes: F18s, the 60ft Tris and Cats in France, and the C-Class. It was quite interesting to have to post the new challenge and most of the team members initially were a little hesitant but I think everyone really enjoyed it; it was something new.

Sail-World: What was the crossover like from soft sails used in monohulled AC boats to the multihulls? Were they similar or different?

Drennan: It was quite a big difference. The sails are quite different in one respect, but initially it was the soft sails in the trimaran; it was just the loads that were so staggering with the soft sails. The main sheet clew load was about 26 tonne on the main sheet. I’ve sailed a lot on the 100 foot canting keel boat Alfa Romeo, and again from that to the trimaran I thought they would give me a nice lead up into the loads that the trimaran would generate, but in reality it was like going from a 40 footer to a 100 footer; it was quite amazing.

Sail-World: What was the mainsheet load that you would get on board a supermaxi yacht like Alfa Romeo?

Drennan: On Alfa Romeo, the main sheet load would probably be six to eight tonne so when you’re trying to get 26 tonne it’s just like another world. It was quite amazing that the highest clew load, on the trimaran, would be in nine to eleven knots; when you’re on the edge of flying a hull, you have to have a massive high sheet load and then once you’re flying the hull it got a little bit easier. That was quite a new experience to deal with those loads with the ramp up to the loads and then as the hull was flying the load would ease.

Sail-World: How did that affect sail design?

Drennan: It was very hard to have the perfect world where the sails were that size and then had to be light, and under the hull flying conditions; and as soon as you were flying the hull there had to be a completely different sail. That’s where the real sail that we saw going from the soft sails to the wing; because the sails were softer it had to be such a dramatic shape change, from not flying the hull andto flying the hull, and the wing could do all of that so easily. We sailed the C-Class catamarans in Toronto several times and they were all wing sails; no soft sails, and that was a really good stepping stone, into where we ended up.

Sail-World: At that stage had you decided to do the wingsail?

Drennan: It was always on the drawing boards, but we all knew what a logistic nightmare and time constraint the wing would provide and the challenges we’d face with that. Also, we never really 100 per cent knew when the America’s Cup was going to be, and where it was going to be, in the early planning stages. That made it very difficult because we had to nail down the height of the mast, and then what sort of conditions it was going to be optimised to. I’m really quite impressed how the design team put it all together with very short lead time to the time the first beams had to be laid for all the wings.

Sail-World: What was the design process you went through? Were you able to use your soft sail design program to work out what the wingsail should be doing?

Drennan: For Mike Drummond and his team it was a new set of rules, and when you look at the wing and you try and compare it to a sail it’s not – and we fell into that mistake – I know I did initially. When you look at the wing you compare it to how a sail should look it’s just a different animal, and we were really well educated that it’s the aero package, so it’s the culmination of both the front and back sails so it’s a completely different deal.

Sail-World: Did you have to learn to trust the computers rather than your eyes?

Drennan: Absolutely. The first couple of times I looked at it I thought it just looks odd, and then when you look on the screen to what the actual flap angles compared to the designer’s targets – as soon as you put it close to those design targets, bang, you’re away. So that was pretty impressive. You really had to re-educate your eye at looking at the aero package rather than just the sail.

Sail-World: So how were you getting that information - via a wrist PDA?

Drennan: It was just a wrist PDA and a bar graph that showed the angles relative to targets. You could change the flap angles to either side of the target, but essentially on target was the right solution.

Sail-World: How was the computer system driven - was it taking readings from the front edge of the mast and calculating the flap settings from there?

Drennan: That in itself was another technical difficulty, because of the height of the mast how much wind sheer there was, but yes, it is just the leading edge of the wing and the flap angles we all just to a target. You obviously had to change them a little bit as the boat got under powered and overpowered, but the targets were surprisingly close from the initial outlay.

Sail-World: It seeemed that USA-17 could go fly the main hull very readily, and stay in 'flight' for five or 10 minutes. What was happening from a trimmer's perspective to get her into that state, was it a quick crank on the mainsheet to get lift-off?

Drennan: Pretty much. If we went back to the soft sails to get the hull flying, the main sheet loads became higher and higher, and then as soon as you flew the hull it would be a massive depower. But with the wing it was a substantially easy process to go from maximum power to a hull flying depower. It was a very small adjustment on the in and out, basically to the traveller, to keep the boat in its hull flying mode, whereas with the soft sail it was a dramatic change with cunningham (luff downhaul), adjusting main sheet and mast rotation and the list went on and on.

Sail-World: When you looked across at Alinghi, with your wingsail and their soft sails, could you see them having the same process that you had stepped away from?

Drennan: Pretty much. You could see that Alinghi were definitely having difficulties, but it was more downwind that was the area that surprised me in the difficulty that Alinghi was having relative to how easy it was for us to keep hull flying.

The actual sail movement on Alinghi that had to happen to keep the hull flying was pretty dramatic from what I saw.

Sail-World: When you were soft sailing, did you have those same problems?

Drennan: We did have those problems but it was also amplified by when we had our soft sails we didn’t have our motor, so we were grinding with grinders so we could never keep up. There was not any chance of keeping up with the sail trim required, especially downwind with manual grinders.

(To be continued)