IRC
HWJ – Heavy weather jib. A headsail of area not greater than 13.5%
foretriangle height squared, and without reef points.
MEASUREMENT
J – The longitudinal distance between the intersection of the fore side
of the mast spar, extended as necessary, and the deck including
any superstructure; and the most forward point on the deck, or
a centreline bowsprit spar, to which a headsail may be tacked,
projected if necessary.
LH – Length of Hull.
LL – The luff length of the largest area headsail on board
LLmax – The longest luff length of any headsail on board.
LLY – The longest luff length of any mizzen staysail.
DEFINITIONS
LP – The luff perpendicular of the largest area headsail on board. For a
cutter rig, LP is measured as the shortest distance from the aftmost
clew point of any headsail when set on the centreline of the boat, to
the foremost forestay.
LPY – The longest luff perpendicular of any mizzen staysail.
LWP – Waterline length. (LH – BO – SO).
Measurement Condition – As defined by Rules 17.1 and 17.2.
MHW – The half width of the mainsail.
MTW – The three-quarter width of the mainsail.
MUW – The upper width of the mainsail, the upper point being the
point on the leech equidistant from the three-quarter leech point
and the head point.
P – The distance between the mainsail (in the case of a schooner,
the foremast sail) upper limit mark, which shall be permanently
marked by a 25mm band of contrasting colour, and the top of the
boom when set at right angles to the mast, or the mainsail tack point
whichever is lower, on the mainmast (in the case of a schooner, the
foremast). If there is no band, the measurement shall be taken to the
top bearing surface of the halyard shackle. In the case of a gaff rig,
the upper measurement point is the peak point of the mainsail or
the head point of the topsail if on board.
PY – The distance between the mizzen (in the case of a schooner,
the mainmast sail) upper limit mark which shall be permanently
marked by a 25mm band of contrasting colour, and the top of the
boom when set at right angles to the mast, or the mainsail tack
whichever is lower, on the mizzenmast (in the case of a schooner,
the mainmast). If there is no band, the measurement shall be taken
to the top bearing surface of the halyard shackle.
as a spinnaker) equal to or greater than 75% of foot length and
Rating Authority – As defined in Rule 4.1. without battens.
Rule Authority – As defined in Rule 4.1. STL – The length of the longest spinnaker pole, whisker pole or
bowsprit measured on or near the centreline of the boat from the
RORC – The Royal Ocean Racing Club.
forward face of the mast spar to the extremity of the spinnaker pole,
Series Date – The year in which the first boat of the class or production
whisker pole or bowsprit, or the horizontal length from the forward
series was launched..
face of the mast spar at deck level to the spinnaker tack point on deck
projected vertically as necessary, whichever is the greatest.
SF – The foot length of the largest area spinnaker on board.
Storm Jib – A headsail of area not greater than 5% foretriangle height
SHW – The half width of the largest area spinnaker on board.
squared, luff length not greater than 65% of foretriangle height,

and not containing aromatic polyamides, carbon or similar fibres.
SLE – The leech length of the largest area spinnaker on board.
UNCL – L’Union National pour la Course au Large.
SLU – The luff length of the largest area spinnaker on board.
Wingspan – The maximum horizontal width in any transverse section of
any wings attached to any hull appendage.
SO – The longitudinal distance between the aftmost point on the hull
and the aftmost point of the waterline.
x – The horizontal distance between the waterline and the lowest point
on the stem at a tangent of 45° to the longitudinal axis.
SPA – The maximum permitted spinnaker area.
y – The vertical distance between the aftmost point on the hull and
Spinnaker – RRS 50.4 shall not apply. A spinnaker is defined as a the aftmost point of the waterline. In the case of a counter stern,
sail set forward of the foremost mast with half width (measured projected to the aftmost point of the hull.
51
Measurement Defs.indd 51 26/11/09 16:50:03
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