Design

The international 2.4mR class

This homepage is built and maitained by Hasse Malmsten

"Design perfection is achieved, not when there is nothing else to add but when there is nothing else which can be taken away"

Can you design a 2,4mR without extensive experience from sailboat design?

 

Well, if you have the lines of a good benchmark that you use as a starting point then the chance of getting away with it is favourable.

Having the lines plan from a successful boat is the best but not likely without paying for a set  of lines from a proven designer.

The lines for the Stradivari and her original certificate data will be published here together with other information that will set the box where most good designs are positioned.

As the metre rule is the oldest design rule still in use it is natural that we are pretty close to optimum. The 2,4 is the youngest class under the metre rule and has "only" been around since the mid eighties.

Some of the first designs were scaled down 6mR designs from the eighties. In the beginning most 2,4 designs was close to minimum width like the early Södergren and Norlin designs. The trend has then been biased towards wider boats since then, the widest being over 0,900 m wide and the narrowest on minimum 0,720 m.

The way the formula is set up together with the penalties for exceeding some certain parameters the rule is type forming a generally narrow and heavy boat.

In the measurement formula length and sail area are interconnected and those two for the speed potential decisive parameters are traded against each other. The longer the boat is, the smaller the sail area and the shorter the boat, the more sail area.

The third major factor determining the speed upwind is the righting moment (RM).

The RM is controlled by the scantlings (the building specifications and the restrictions imposed on them).

The specified minimum weight for the hull and deck mouldings (3,6kg/sqm) and the minimum weight for

the mast and rig, determines how much of the boats weight can be lead ballast located in the keel.

SWE 430, a Stradivari amateur built in female moulds.

Certificate for Stradivari in original trim.

PDF

      2,4mR designs

Here we will present information about the different designs that has been or is sailing in the class.

We would be greatful to receive more material on especially the Howlett, Odd and Ängermark designs. If there is some designs we have missed please tell us.

Links to useful information