Feedback

Would I risk a Millennium Rig? First I would like to disagree with Andy Rice in the statement about the handicap success of the Kers. If anything the IRC results this year were dominated by the Swan fleet and IRM was dominated by the IC45, a 1996 design. The millennium rig on Roaring Meg fell down more than once and during the Commodore's Cup the crew were repeatedly told to stop altering the standing rigging while racing.

Jason maybe missed the point with an IACC rig as there is a minimum weight and centre of gravity and any saving (by reducing spreader numbers) can go into the laminate to make the tube stiffer so the IACC rig is not small in section and it is held very straight.

Jason Ker replies
Firstly, before making bashing attacks on competitors, Mike Richards should declare that he works for Farr International Europe, and his views should thus be understood in that context.

Secondly, Mike feels moved to rebut the notion that the 11.3 is "the success story of Solent handicap racing in 2001", by pointing out that "IRC was dominated by the Swan fleet and IRM was dominated by the IC45 a 1996 design"... Yes the Classic Swan 65 Desperado beat the 11.3s at Cowes in a continually windy week, but where is the story in that! The IC45 was successful in IRM this year for two reasons:

1. It has a very competitive rating due to its 2.6% age and overhang allowance.

2. IC45s have been sailed at the highest level since 1996 and their sailors are relatively far ahead along the learning curve towards knowing what makes them tick. The corrected times in IRM towards the end of the year became very close, proving not only what a good rule IRM is, but how well it accommodates some existing yachts. What Andy Rice probably had in mind when he made his statement was that the 11.3 has probably been the only boat this year that has been truly competitive in both IRM and IRC. The IRM age allowance is being reduced 0.25% for next year.

Thirdly, the only reason that Mike, fifteen months after the event, still remembers that Roaring Meg's crew were said to be tuning their transverse rigging during the second day of the Commodore's Cup (it was the first time the brand new rig had seen more than 12 knots of wind), was because that race, the untuned 35.5ft boat beat two thirds of the 41ft Farr 40s across the finish line... after all, having crew up the mast on a 35 footer is hardly a fast way to sail either.

Fourthly, I did not "miss the point with an IACC rig", because any comment by myself about the potential weight or centre of gravity reduction was clearly referring to our own 2000 IRM designs. The IRM rule has no minimum section size restrictions, and for certain rig configurations, its minimum weights and centres of gravity are quite difficult to achieve.

Fifthly, as one of the very few designers who knows a bit about Millennium rig types and is free to comment through not having any IACC involvement, I should explain that the significant gain by going to a millennium rig configuration for the IACC teams is not the weight of one set of spreaders, though there is a gain there, it is primarily the reduction in the transverse section inertia requirement, through having more support points along the tube. The benefit of this reduced requirement can be taken in several ways:

1. Material can be taken from the side walls and placed at the fore and aft faces of the section, either allowing the mast tube to be shorter in the fore and aft direction for the same stiffness, or alternatively making the mast stiffer fore and aft (note that there is a minimum section width and length of 150mm and 300-260mm respectively up to the I point, which prevents IACC Millennium rig designers from taking the gain in the form of a narrower section)

2. The section shape can be made more aerodynamic, and less structurally efficient, i.e. less rectangular.

3. A side benefit of 1and 2, is that the mast tube becomes less stiff torsionally, allowing more twist.

It is my view that the failures in Auckland could be due to any of the following reasons, plus others:

a. Local instabilities of the relatively thin section side walls that are achievable.
b. Specifying a low proportion of off-axis material in an effort to create more twist.
c. Allowing the leeward vertical rods to become slack while heeled in an effort to create more twist.
d. Having such a bias in the section properties towards fore and aft inertia, that the mast is unstable in fore and aft bending under runner load.
e. Simply just going too fine on the overall margins of safety, ie perhaps through taking 100% of the theoretical benefit of the configuration without appreciating all the connotations.
f. Seriously close-to-the-edge rigs require accurate handling and a slightly mis-calibrated load cell or a loss of concentration from a crew member can be all it takes to send one over the side.
g. In the case the TNZ failure, perhaps purposely putting the 'scares' on the other less experienced Millennium rig users!