A designer's viewpoint

Yacht designer Jason Ker gives his thoughts on IRM and the prospect of a new international grand prix rule

Jason Ker is one of the few yacht designers who have specifically designed boats for the IRM rule and has had four different IRM designs commissioned. His Ker 11.3 one-design, ten of which have been built, have been successful under both IRC and IRM, but Ker says that lack of international support for IRM has meant that his clients have more recently chosen to commission IRC designs including a 55 footer to be launched shortly.

Ker partly credits RORC/ORC politics for the slow take-up of IRM inside and outside of the UK. “It also never had any genuine top down support during the critical phase and as soon as it was born it was dropped by its parent. There have been new noises made by RORC about it being supported and I think now there is a change of leadership in RORC it may see more support and it is getting quite good bottom up support in the Solent.

“For example in the Hamble spring series there is an IRM class and an IRC class and the serious racing - with two races per day and a bunch of 40 footers that are overtaking each other round the course - is being done in IRM. Whereas in the IRC class there is one race per day with a wide variety of boats from a 65ft Swan down to sports boats.”

So what are the good points and the bad points about IRM? “The good thing about IRM is that the boats are fast and they are typeformed in a fairly fast way. The bad things about it are the same virtually - it is very type forming and quite restrictive.” This may be another reason why the rule has yet to find whole scale appeal.

The problem with getting international agreement on a new rule that typeforms may be reaching agreement on what the typeformed boat should be. All rules typeform and he says this is the problem with IMS. “The Volvo 60 and America’s Cup rules are type forming and very successful rules. IMS is in theory isn’t typeforming – it tries to rate all comers but actually it typeforms quite strongly too. IRM also typeforms but in a direction which is positive whereas IMS tries to take all comers but ends up type forming in a fairly negative direction.”

Hence the two rules are poles apart in their philosophies. “If you had to sum it up IRM encourages speed and high tech, quality construction and engineering-design and so on. Whereas IMS tries to rate everyone equally regardless of the quality of construction and so on, so it ends up leading people down un-natural design paths. But that is an old debate.”

A good example is their construction. Top IRM and IMS boats are both built in carbon/Nomex but for completely different reasons. “Under IRM if you have a lighter boat construction - if you do a better job of engineering your boat - you can have a heavier bulb and/or a narrower waterline beam and can go faster. Under IMS the benefit for good construction is just centring the weight in the middle of the boat which helps you in certain ways, but it is not such a significant overall benefit.”

The resultant typeforms created under IRM and IMS are very different. “With IRM the controls on the speed of the boat are very minimal. It pretty much gives you a fairly free canvas on the hull shape and the centre of gravity so the IRM boat ends up being relatively fast. The IMS boat - the only real objective has to be to beat the VPP, that can mean being slow but rating even slower or it can mean being fast and rating less fast. So there is no real control over where the typeform leads. At the moment the typeform ends up with fairly undesirably shaped boats that go well under the rule but they are not fast for their size, as has always been the case since the early 1990s with IMS boats.”

Under the IRM rule, he says, the typeform was intended initially to be very tight and then to gradually loosen over time as confidence about the type of boats it was creating grew. Although a small amount of loosening with the rule has happened already, he suspects that if IRM was going to get broader support it would need to have its typeform loosened further to allow more boats that already exist to race under it competitively.

IMS in its present form doesn’t make for a good grand prix rule Ker feels. “You can build yourself what you think is a state of the art one-off racing boat and someone can turn up next to you in a production cruiser racer and be virtually as competitive in flat water. That is not satisfactory for a grand prix rule.”

The complexity of IMS is possibly one aspect of it that has worked against it in the UK and the US, whereas in the Spanish and Italians have become happy with it. “It might be that the more extensive measurement you get with IMS is something that might be accepted with a grand prix rule, but I wouldn’t like to say. You’d need to survey owners to find that out.”

Generally he thinks that for club racing or big fleets of widely differing boats you need a rule like IMS or IRC that tries to rate everyone equitably: “A rule for everybody where the most basic boats and the most racy boats can come together at club level or any other level it is chosen to be used at, is necessary because there are not enough boats in the water to split people up at club level. You need to be able to race all the boats that are available together under one rule.”

But he also thinks there needs to be an additional grand prix rule to encourage those people who want to use the best technology, engineering and design. “There is an additional need for a rule for the people who want to go off and race more seriously at an international level and push the boundaries. And I think that has been what has been recognised.

The wide reaching IMS/IRC type rule and the grand prix rule should be related. “Boats are not always going to be staying in one tier. They might do 90% of their racing under a general rule, but they can go off and show their faces in big events under the international rule.

“A good thing about IRM is that the typeform is successful under IRC as well. That is pretty fundamental. If you design a new boat to the international rule and you take it out in your local club event, you have got to stand a chance of winning. You may not have the most competitive boat there but it must be on a par otherwise people will feel resistant to it. That is one of the things which has been successful with IRM. The IRM typeform is not the most competitive shape that you could have for the purpose but it is close enough to give IRM boats a good shot under IRC. But it is also important that there is the political will to use the rule for the right purposes because other people will say most of my local racing is in IRC and not many race organisers are using the new grand prix rule so therefore I’ll just commission my new boat to be designed to IRC.”

The whole point of IRM he says was to take the pressure off IRC and to prevent the serious racers working the rule. “If IRC trophies were the only thing that mattered for an extended period of time then race boats might be typeformed in quite strange ways. At the moment, when designers are commissioned to design racing boats for IRC, they are still designing fast, fun boats to sail, but if the competition starts hotting up then that wouldn’t necessarily stay the same. In IOR there was very fierce intense and sustained competition to have the best IOR boats at the Admiral’s Cup or the One Ton Cup, so the boats ended up being quite bizarre.”

This could be a problem if a new grand prix tries to fit in with IMS in its present form. “I can see the new rule fitting into IRC, because IRC will rate fast boats no problem. It is not the same with IMS at the moment. So they will probably have to tweak IMS at the same time if they are going to make it stick.”

Another problem will be how to deal with the major technology advances that are going on in yachting at present. “If they are trying to be typeforming then it is quite difficult to encourage development. They almost have to start with those developments in mind and say we are going to allow all sorts of things and be quite free with things like appendages. But then there is the risk of things moving on quite fast and owners being left behind with their first generation boats. There is a balance to be struck there between having a rule that encourages design development but keeps people competitive for more than one season.”

Ker believes that the two most hopeful prospects for a new grand prix rule would be either one that is a VPP-based rule – like IMS – but one which typeforms positively to promote fast boats - like IRM, or a development of IRM with a looser typeform. Either way a lot of work would need to be done before such a rule could be released and he sees IRC continuing to grow as the main rule for the majority of the worlds racing fleets both before and after the release and widespread uptake of a new International Rule.

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