Eldon,
No, there was no error.
Without want to appear pedantic, you will have seen the update from Bram
confirming that the overall tolerance bandwidth is 1/2" (12mm).
More importantly, it is important to note that the official measurement system
for the class is metric. Imperial measurements are given for convenience only.
Ron
Brisbane, Australia
PS
Just to be a little pedantic - the expression Imperial measurement system is
now an anachronism - it really should be US system - because the politically
influential US military/industrial complex are the only Luddites who haven't
seen the wisdom in adopting what is otherwise now an international standard
having unquestioned advantages.
Thankfully, Bram and others contributing to the development of the rules for
this class have had the wisdom to adopt that international standard from the
outset.
Ron
----- Original Message -----
From: Harveynestor@xxxxxxxxxxxxx
To: swiftsolo@xxxxxxxxxxxx
Sent: Thursday, November 27, 2003 1:33 AM
Subject: Reply to Ron Deane
Ron:
You are in error.
1. Bram's claim regarding the 1/2" tolerance conflicts with his proposed
rule.
Bram's claim: "You are required to build your boat within a 1/2"
(12mm.) . . ."
Bram's Rule: "The hull tolerance with the exception of the transom
shall be plus or minus 5 mm ..." (Appendix 3 of the proposed rules,
Instructions to Measurers).
Discrepancy: 5 mm is not the same as the 1/4" (6mm) Bram claims.
5 mm is not 1/4 (25%) of an inch. 5mm (5/25.4 = .19969) is 19.7%
of an inch--13.5% less than the 1/4" tolerance Bram claims exists.
Even 6 mm is not 1/4" (25%) of an inch. 6 mm (6/25.4 = .2362) is
23.6% of an inch.
2. There is also a subjective test associated with Part B, Rules 5.12.2 (b)
and 5.12.2 (c).
Rule 5.12.2 (b) states: The hull shape shall conform to the designer's
drawings within the tolerances specified by the Measurement Diagrams and these
Rules. Note, tolerances are provided on hull measurement stations and points
to allow for building inaccuracies only. Any attempt to design within the
tolerances will not be allowed.
I have not received the designer's drawings, i.e. plans, for which I
paid Bram. Have you?
If one has no drawings from which to measure his hull, how can he be
assured that his completed boat will fit within the tolerance of 5 mm? and pass
the subjective test?
Wouldn't it be more fair for Bram to provide ALL builders with a copy
of the plans (assuming that they have paid him) so they can correct any errors
in construction prior to completion rather than risk thousands of dollars and a
lot of time in the construction process only to be accused of having tried to
"cheat by re-designing within the tolerances"?
5.12.2 (c) states: If a measurer believes that a Swift Solo has been
built with deliberate variations from the full size frame template drawings,
the measurer must refuse to fill out a hull measurement form.
How will the measurer conduct his subjective test?
3. Conclusion:
In reality:
a. not only is Bram's claim of a 1/4" (6 mm) tolerance inacccurate
because it is not written in his rules, but
b. the 5 mm tolerance that is written in the rules is only a
possibility based upon a measurer's subjective opinion.
Consequently, the only boats that can be assured of measuring in will
be the CNC boats.
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