> The rules allow any piece of equipment not mentioned in the rules to be
open to innovation.
> As far as the foils go here is my understandings of the text.
a. Only one centerboard and one rudder shall be permitted in a contest. A
measurer may
approve replacement centerboards/rudders if these are broken.
b. The rudder and centerboard shall each consist of single vertical foils.
They shall not be
ballasted and shall float.
> My interpretation of these rules is that you cannot have an arrangement
with 2 CBs in the water however you might concoct their joining or
deployment (say underwater lifting foils) and it should float horizontally,
that is, not tip down.
c. The centerboard may be of any construction or plan and sectional shape,
provided that
it does not exceed the maximum plan profile shown in the full size
measurement
diagrams or the dimensions given in Appendix A and Instructions to
measurers.
> We should circulate the instructions to measurers, (read - we should write
them) but these instructions with respect to the CB will be as Christian
suggests a box that has a maximum depth and a maximum width (close to the
slot maximum). The measurer will lay the board on the plan diagram and
check that none of the board is outside the box.
d. Maximum width of centerboard, perpendicular to the chord and longitudinal
axes, is
36mm (1 3/8 inches)
> Set by the slot width. So pretty much any type of CB that will fit the
slot but not deeper than some measurement. That fits Christians suggestion I
hope.
e. The rudder shall match the profile and section defined by these class
rules.
i. The official rudder foil of the International 49er class shall be
acceptable.
ii. Alternatively, rudders may be built to comply with the section and
profile
designated by ISSA.
iii. Rudders built to tolerances that fall between the official ISSA
sections and
profiles and those of the official 49er rudder shall be acceptable.
f. No appendages shall be allowed below the waterline on the
i. centerboard or
ii. rudder
>The Rudder is another kettle of fish. We want the boat to work out of the
box (off the plan). Obviously there will be a tendency on both foils to
decrease the cord and the section thickness to lower drag. This kind of
experimentation will result in thin rudders causing catastrophic broaching
under load at speed downwind. You don't want this, and I don't want you to
do it near me either. :-)
The intent of this rule is to make people use a rudder plan and section that
has been honed by the best minds in skiff sailing in over 20 years of high
speed experimentation. The combination of these foil section shapes will
make the boat sailable by all but the most ungifted sailor. Those that have
skills like Bertrand or Coutts and can steer with incredible feel and steer
the narrowest bead would get away with a critical low drag foil. The rest of
us will crash and burn. When a gust dies very suddenly the 49er rudder foil
section (on a level planing boat) can support two crew on trap (without
teabagging them) for a short time without ventilating catastrophically. The
consensus is that the 49er foil, off the shelf, is better matched to the
Swift that the 49er, So I think we should go with that. I don't like the
49er rudder boxes so I am happy that we can do as we like in that area, it
is not mentioned in the Rules, except that it is to be part of the hull for
the purpose of weighing. So keep it light and make sure it is strong. The
tolerances and sections alluded to in the Rules will be similar to (read-
lifted off, but respecting copywrite) the 49er rudder and since this is a
quality piece of equipment from the 49er Builders Association I am very
happy to buy one off the shelf. What do you all think?
g. The centerboard may be shaped or fitted with any device by which it will
adjust itself or
may be adjusted or pivoted about its longitudinal axis while racing.
> Finally this rule was tacked on the end to allow gybing boards. It might
also be construed in other ways to allow other arrangements including trim
tabs etc. (Knock yourselves out if you can make a better mousetrap, "nobody
to date has been able to get over the drag penalty of a hinge" quote Julian
Bethwaite. I guess he would know). Moreover, you might also notice a crafty
little interpretation that says appendages are things that will not fit
through the slot. That would relax the appendage rule in effect in other
classes and allow some sort of tiplets if you want to experiment with them
to decrease tip loss. Lifting foils however are expressly prohibited (in
competition). Anyone who wants to fly in a monohull skiff should look for
inspiration to Rohan Veal's incredibly fast foiler Moth. International 14s
have flown and rumor (from JB) has it that 49ers will fly soon, why not a
Swift. Love to see it!
My 2cents ......
Greg
Rose - USA009
----- Original Message -----
From: "Christian Rasmussen" <christian@xxxxxxxxxxxxx>
To: <BDally6107@xxxxxxx>
Cc: <swiftsolo@xxxxxxxxxxxx>
Sent: Thursday, March 11, 2004 3:09 PM
Subject: Re: potential rules changes and sail testing
>
> While we are at it. Could we nail down the specific dimension rules for
the CB, Rudder box, and Rudder?
>
> I would like to leave them fairly open with some max/min dimensions. No
restrictions on foil shape, besides to adhere
> to the max width/lenght dimensions we decide on? After all we are trying
to encourage innovation here. Right?
>
> Thanks,
>
> Christian
>
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