Quarter Ton Design Rule

Hi all,

Ive been trying to dig up information on the design rules for the IOR quarter ton class, but im not having much luck.

Does anyone know if there is a specific set of rules to design the boat to the correct ratings. There seems to be a bit of a resurgance in this class back in the UK, but almost all of the boats were produced / designed upwards of 15 - 20 years ago, as far as i can tell.

Can anyone help?

Cheers
Rich

 

I think most of the quarter tonners were designed in the early seventies Rich. All I can tell you is that they were designed to rate 18 feet. Practical boating magazine often has tests on old quarter tonners and mentions some of the criteria.

I own a quarter tonner myself that was designed by Ben Lexcen in 1970. The boat is known as a M&W 26, this was when Ben's surname was Miller. Quarter tonners vary from 24 feet to 27 feet and several successful ones went on to be successful production boats. What I gather from magazine articles is the resurgence in the class is mainly because of large numbers of existing boats and their very low prices. My boat is 26 foot long and nearly 10 feet wide, hell of a lot of boat for the money and very pleasant to sail

 

Sounds like a good boat, your not based around melbourne by any chance?

I will keep digging around for the rules. Thanks for the info

rich

 

http://www.orc.org/fileadmin/user_upload/download/clubook.pdf

Sorry, that was a kind if simplified ims...
Seems like orc has forgotten ior

 

ORC does still sell the IOR rule, but they want 12 pounds for it...plus postage.

Quarter tonners rated less that 18.0 feet under the IOR rule. The complete IOR Mark III rule is included in the book, Sailing Yacht Design by Douglas Phillips-Birt, third edition 1976.

The rule is an equation; RATING = MR * EPF * CGF * MAF


Tad

 

For the resurgent 1/4 Ton Cup, all entries must have held an IOR Rating of 18.5ft or less at sometime during the years 1970 to 1996.

I think this precludes building a new boat. The idea is to use up all the cheap old boats that are lying around, which although they rate okay under IRC, aren't what most people think of as 'good all round multipurpose boats'. (Particularly the more extreme ones).

The 1/4 ton Cup is back in France this year and it will be interesting to see how much interest this generates in what was always their spiritual home.

 

I will have to look for a different rule set to attempt a design with then. I was thinking at trying a box rule design but I liked the idea of having a little more fredom.

Cheers for the info
rich

 

One Norwegian, Mr Birger Kullmann (www.kullmann.no), did his master thesis on optimization for the IOR. He (and a co student Mr Mowinckel) built and towed several models. They found a way to cheat the rules by having a quite distinct hollow area in the aft, where the girth length is measured. The optimization process seem to be "how much can we change the shape from good to bad before the boat is slowed down more than the rating goes down."
Later they built some minitonners (IOR rating 16 feet?) “Wet Dream”,“Norwegian Wood”,“Touch Wood” and did quite well.
They studied a few years before me and I read their paper with great interest.

 

Well, if it's a box rule that interests you, there is a new rule, Classe 9,50 that has been promoted recently to fill the gap between the MiniTransAt 6.5m and the Class 40's (whose rules are also available). There seems to be a lot of interest in this size of boat and especially with the cost constraints they have included. The rule has some interest in that it has a trade off between allowable water ballast and beam, as well as a requirement to make OSR Cat 1.

http://seasailsurf.com/seasailsurf/actu/spip.php?article4265.

But if you want a complex rule with plenty of trade offs, there is still plenty of life left in the Metre rule. Although the rule is 100 years old this summer, new boats are still being built, especially the 6m and off course, the same rule is very lively (and cheap) at its 2.4m version.

Finally I have included the ORC level rating rules. I would be cautious about these and the Open 30 rule, etc, as it's difficult to predict if there is much milage left in these rules.

 

South coast NSW. I would not consider building a quarter tonner even if the class allowed it. Too many quarter tonners about in various guises. Just pick the hull type to suit the sailing area and optimise the boat.

 

I think the ORC Grand Prix 26 "box rule" is the most close successor to the 1/4 to class. Fast, no nonsense, round the can's racer.

The rules are available for free from the ORC website.
http://www.orc.org/index.php?id=163

 

Seems like and interesting rule.
Are there many boats built?

 

Not yet, as the rule is only in it's second year the first one's are now emerging. Abouth 25 of the GP 42 are under construction now as that is where the most money is.

I expect the 26 to get more popular when the production builders get their boats of the line like this Russian one http://foto.ricochet.ru/displayimage.php?album=9&pos=0

 

Funny
I searched for som more info on the GP26, and guess what,
"Is this the new quarter tonner?" .....
http://www.madforsailing.com/ism/ar...E75B35E12802572740038C509?OpenDocument&Page=1

 

Is this the new quarter tonner?

Well, I would repeat my cautious note expressed earlier about this rule. There certainly has been some interest in the GP42 level, but (almost?) none at the GP33 and only some at the GP26 size. I guess it depends on where you sit in the worldwide debate about rating rules, to know how you interpretate these numbers. Obviously people in the IMS hotspots of Holland and Italy are going to be more optimistic than, say us in the UK.

Sailing boats of this size (26' or 8 m) have changed greatly since the best days of the 1/4 Ton rule. Sports boat one-designs are now popular with those who want to race inshore, with a glut of different models, of which some (J80 for instance) establishing fairly widespread fleets. But where you do not have a one-design fleet, your chosen sports boat must rate well under whatever rating rule is used locally. This is where sportboats have come unstuck as they have generally been treated harshly by these rules.

You will get the same problem with the GP26. Level rated fleets are going to few and far between. So how will they do under handicap? Well, IMS should be okay, but what is its future? Certainly it would be a gamble to choose a GP26 to sail under IRC when cheaper, proven alternatives like the Corby 26 are readily available. The GP26 is also llimited to asymetric kites which again don't always work well in mixed fleet racing or in narrow tidal waters where you are often forced to sail dead down wind and ignore the angles.

Racing further offshore, (like they did in the 70's with the 1/4T boats) is now becoming increasingly restrictive because of the need to reach OSR Cat 2 for many races. If this type of sailing appeals, again for less money than building a GP26, you can buy a Corby 29 (RCD Cat A) or even build to the new Classe 9.50 which again will have to be RCD A / OSR 1.

So, looking into my (albeit UK centric) crystal ball, I can never see GP26 getting anywhere near the same numbers worldwide, as the 1/4 Ton boats did. Not by a country mile. On a good day. With the wind behind them.....