Tom Schnackenberg on the nuances of barge design

Tom Schnackenberg
Long time America's Cup design guru Tom Schnackenberg is now working with America's Cup Management on various design tasks, one of which was with the development of the AC90ft rule, which has been widely acclaimed.

In the following interview published on Alinghi.com, Schnackenberg outlines what he would expect to see in a 90ft by 90ft America's Cup Challenger:

We’ve been reading a lot about the AC90, what would your role become if Alinghi is required by law to accept the GGYC challenge as it has been lodged?

If that becomes the case, then my role would change rather, that is should ACM be consulted and be managing the defence.

The first thing I would have to do is to have a good think about the nature of the boat that is challenging, how the racing should be organised and what things would need to be put in place to ensure the racing is proper.

You’d be well qualified having had experience of unconventional challenges in the past – tell us about that?

That’s true, I was invited to Annapolis by Michael Fay back in 1987 and on the way there he opened a copy of the Deed of Gift and read out about five lines to me which basically set out the requirements for a challenge as they were in 1887 and have been ever since. Among those was the fact that the challenger would supply a certificate of the yacht including the name of the owner, the name of the yacht, the rig and the four key dimensions, being the waterline length, the waterline beam, the maximum beam and the draft. These dimensions couldn’t be exceeded, presumably they could be made a little bit smaller, but the idea would be that these would be the dimensions of the yacht.

Can you give us the in-brief of the BMW Oracle Deed of Gift challenge?

The length is 90ft, the beam at waterline is 90ft and the extreme beam is 90ft which suggests that the boat is plum sided at the extremes. The hull depth is 3ft and there is an extra mention of the draft with the boards down being 20ft. So to me, if you think of waterline length you imagine running your hand along from the bow of the boat, it goes under the water at a certain point and continues under the water until it comes up 90ft later and that’s the waterline length.

Sounds like a bit of a barge to me?

Well if you use the same process to determine the waterline beam, then you go down at one point and you continue under water until you come up at another point and that’s 90ft away, so yes I suppose ‘barge’ would probably be the best single word to describe what we are talking about.

What are the perceived advantages from the GGYC/BOR’s point of view in creating a challenge such as this?

Perhaps, if they were thinking of opening up their design space and having smaller beams, the advantage would be that they are not limiting themselves, but I think in fairness to any Defender, they would want to stick to the boat that they have described.

I talked a little bit to Rolf [Vrolijk] about it, because the Dutch are renowned for designing barges and particularly barges with leeboards which can sail quite well. Even though he is excellent and inventive, it was obvious that he had no experience in barge design and neither does Dirk [Kramers] and so they are at a little bit of a handicap.

Presumably we would have to hurry up and learn how to do this. How long do you think BMW Oracle could have been working on their boat?

It’s hard to know, months obviously and possibly years. The challenge was lodged on 11 July 2007, but obviously they thought about it a long time before and so they have a big design edge and the Alinghi guys, I think, just hoped it would go away and depending on the court action, it could be a non-starter as there is a very tight timeframe. The 10 months notice would obviously be extended by the court action and the time it takes to do that, so that period will probably only start after the court order has been handed down.