Juanpa Cadario: Declaración del comite de medición con respecto al uso de un canting keel.

Declaración del comite de medición con respecto al uso de un canting keel.

En la primer semana de mayo, el Comite de Medición de la America´s Cup publicó sus últimas decisiones relacionadas con el uso de un canting keel (quilla basculante) en la America´s Cup 2007.Por primera vez fueron mostrados dibujos que muestran qué es lo que se entiende como canting keel. El concepto es que la estructura de la quilla esta alojada dentro de una caja, y le permite bascular (to cant) a sotavento justo antes de que el barco vire.Cuando el barco ha virado la quilla es inicialmente desviada ofreciendo un poder de adrizamiento (righting moment) mayor antes de volver a su posición central. La ventaja de este mecanismo sería que proporciona poder de adrizamiento adicional justo después que el barco ha virado, dando más potencia y aceleración pero incrementando levemente el abatimiento (leeway).
A continuación la interpretación oficial en inglés y cuatro diagramas que forman parte de la explicación:

ACC Version 5.0 Public Interpretation No 38 May 8, 2007

In response to the following:
Please issue a Public Interpretation in response to the following questions to clarify the restrictions under ACC Rule (Version 5.0) on altering the support of a fixed appendage to vary the heeled righting moment while racing:

1. With reference to the answer in the second paragraph of PI 32, does the term ‘components’ include reference to a) hydraulic cylinders,b) locking systems, or c) structural response damping systems any of them, with moving parts or variable geometries?

2. 2. With reference to answer 4 of PI 22, would a fixed appendage supporting structure that deforms gradually over time, either due to a) creep, b) passive locking system, or c) the presence of a damping system, contravene the requirements for a fixed appendage within Rule 17 or any other Rule?

3. 3. With reference to answer 9 of PI 22, would the requirements for a fixed appendage of Rule 17 also be contravened by the constraint of a fixed appendage in a deflected position arising from the hydrodynamic and gravitational forces as described in answer 4 of the same PI 22? (i.e., Is it permissible to constrain a fixed appendage, by a mechanism which would maintain the deflection either to one side or the other, while deflected to leeward before tacking resulting in some deflection to windward, or less deflection to leeward, on the new tack?) (See as examples Figures 1 & 2).

4. 4. Would the answer to the previous questions be similar if the fixed appendage, or its supporting structure, was not fully constrained but instead restrained thus producing a similar but time dependent behavior when changing tacks (ie, the fixed appendage would gradually return to have similar deflection to leeward on both tacks over some finite period of time)? (See as an example Figure 3).

5. 5. Would the control or adjustment of the constraint or restraint of a fixed appendage while racing contravene rule 17? (See as an example Figure 4).

INTERPRETATION:
1. Yes. However, any component as described with moving parts or variable geometry shall be fixed, and if deemed necessary by the Measurement Committee, disabled to prevent movement, alteration or adjustment whilst racing.

1. 2. Yes, an appendage that is supported by structure that alters the deflection of the appendage due to gradual deformation either due to creep, a passive locking system or a damping system would be considered to be a moveable appendage. If the axis of rotation of the appendage is not at an angle to the MWL plane exceeding 45 degrees then it will not comply with Rule 17.10 (b).

2. 3. Possibly. The definition of “fixed” as used in Rule 17 would be contravened if a fixed appendage was constrained by a mechanism which would maintain the deflection to leeward before tacking resulting in some deflection to windward, or less deflection to leeward, on the new tack.

3. 4. Yes. See answer 3 above.

4. 5. Yes. See answer 3 above.

The supplied attached sketches form part of this interpretation
END

This interpretation is made by the Measurement Committee in accordance with Rule 3.3 of Version 5.0 of the America’s Cup Class Rule.

Ken McAlpine ACC Technical Director