|
The A Class Catamaran is controlled by
the rules set down by the ISAF under the “Rules for the Divisions of
Catamarans and The International C Class ” (Last
issued May 1985), which are as follows:
1. A catamaran is defined as a two-hulled
sailing boat with essentially duplicate or mirror image hulls, fixed in
parallel positions.
2. Sail area shall not be more than:
13.94 square metres (150 square feet) Sail area to be measured in
accordance with the ” IYRU Measurement & Calculation of Sail Area
Instructions” (Last issued May 1985)
3 The overall length of the catamaran
shall not be more than: 5.49 metres (18 feet) The length shall be
measured between perpendiculars to the extremities of the hulls with the
catamaran in her normal trim. The measurement shall be taken parallel to
the centre line of the craft and shall
exclude rudder hangings, but if the athwartships width of a rudder
within 153mm (6 inches) of the bottom of the hull is more than 76mm (3
inches), the length shall be taken to the aftermost point of the rudder.
4. The extreme beam shall not be more
than: 2.3 metres (7 ft 6˝ inches) The beam shall be measured at right
angles to the centre line of the craft at the widest point and including
all fixed or adjustable apparatus with the exception of a normally
accepted trapeze or retractable seat.
5. The crew in Division “A” shall be
one person ( helmsperson)
6. Unballasted retractable seat or
trapeze shall be allowed for the helmsperson. When in use the helmperson
at all times shall have at least one foot in contact with the boat.
7. The A Division emblem shall be carried
on the mainsail and shall consist of the letter A over two parallel
horizontal lines over national letters and sail numbers, Sail numbers
shall be allotted by the National Authority or Class Association
appointed by the National Authority. The class emblem, national letters
and distinguishing numbers shall be placed as prescribed in the Yacht
Racing Rules. ( RRS 77 & RRS Appendix H )
8. Hydrofoils are not permitted.
9. Minimum weight in full sailing trim
shall be not less than 75 kilograms.
MEASURER’S GUIDE TO COMPLETION
OF MEASUREMENT FORM.
All A Division Catamarans shall have a
valid measurement form and for all yachts measured after 1st January
1998 it shall be on the latest style form dated 4/97. This form is
composed of four separate areas that are largely selfexplanatory.
The following notes should assist
in their understanding.
Mast & Boom Measurement Form
The purpose of this measurement is to
find half the total area of the mast and any mast base fitting attached.
On a straight section (i.e. not tapered) it is simply the length L x
half the mast girth.
The Measurement and Calculation of Sail
Area instructions defines girth as follows: “The girth measurement
shall be taken as the distance from the centreline round the surface of
the spar to the same point on the centreline. The resultant dimension
shall be divided by two to give the half girth measurement.” Should
mast be tapered extra measurement U1 & T need to be taken and the
formulae on measurement certificate utilised. Black band measurements L1
& L2 play no part in the mast measurement at this stage.
Boom measurement is only utilised if the
profile height of the boom is more than 1.5 of the width.
Hull Measurement
This area is self explanatory with only
two measurements needed i.e. width & length. Things to look for with
overall length are: If the width of a rudder within 153mm (6 inches) of
the bottom of the hull is more than 76mm (3inches) the length
measurement needs to go to the aftermost point of the rudder. With the
width, measurement is at the widest point of the hulls, this may be at
some point down the sides of the hulls, especially if hulls are angled.
It may also be possible that the maximum width is at bottom of
centreboards when fully down.
Sail Measurement Form
When undertaking the sail measurement the
following points should be noted. Sail to be measured on a flat surface
and laid out in terms of IYRU Measurement & Calculation of Sail Area
Instructions. i.e. “With battens set in their pockets the sail shall
be pegged out on a flat surface with just sufficient tension to remove
waves or wrinkles from the edge rounds and to spread the sail, as far as
possible, substantially flat. Once the sail has been pegged out in this
way all the required measurements shall be taken and no alterations
tothe tensions shall be made.”
Luff length A is the maximum distance
from the head to the tack of the sail. It is taken on the inside of the
boltrope, which is not included in any measurement.
Base length P is a measurement from the
clew to a point at 90 degrees to A.Measurements M, F, K, D & H are
all made at 90 degrees to their respective lines.
All are to be the maximum distance that can be
taken.
General Calculation Form
This form brings all the measurements
together and all that is required is to transpose measurements from the
other forms. On this page it allows you to calculate the theoretical
Black Band distance that will allow a maximum sail area of 13.94 square
metres for each sail that the boat may have. It should be noted that
black bands should be on the mast and form part of the measurement
requirements.
The weight of the boat and any correcting
weights are also listed on this page. The weight of the boat consists of
all items associated with the boat in full sailing trim. It does not
include such things as shackle keys, water bottles, spare rope etc.
The boat must be weighed in a dry
condition and any weights attached to bring the boat to a minimum weight
of 75 kilograms must be permanently affixed and their weight duly noted
on this page.
|
