IRC YEARBOOK 2009
LL – The luff length of the largest area headsail when stretched I
R
sufficiently to remove any creases.
C
LLmax – The longest luff length of any headsail when stretched

M
sufficiently to remove any creases.
E
LLY – The longest luff length of any mizzen staysail, measured as for LL.
A
LOA – The length overall of the hull excluding bowsprit and other rigging
S
if any, stem fittings, stern fittings, pulpits, any overhanging rudder U
and rudder hangings.
R
LP – The luff perpendicular of the largest area headsail measured as the
E
shortest distance from the clew point to the outside of the luff or luff
M
tape. For a cutter rig with more than one forestay, LP is measured as
E
the shortest distance from the aftmost clew point of any jib or headsail
N
when set on the centre line of the boat, to the foremost forestay.
T
LPY – The longest luff perpendicular of any mizzen staysail, measured
D
as for LP.
E
LWP – Length on waterplane in the condition of Empty Weight (see
F
Rule 22.0).
I
N
MHW – The half width of the mainsail, measured as the shortest distance
I
T
between the half leech point and the luff, bridging any hollows in the
I
leech of the sail.
O
N
MTW – The three-quarter width of the mainsail, measured as the
shortest distance between the three-quarter leech point and the luff,
S
bridging any hollows in the leech of the sail.
MUW – The seven eighth width of the mainsail, measured as the shortest
distance between the seven eighth leech point and the luff, bridging
any hollows in the leech of the sail.
Movable Ballast – Lead or other material including water which has no
practical function in the boat other than to increase weight and/or to
influence stability and/or trim and which may be moved transversely
but not varied in weight while a boat is racing.
P – The hoist of the mainsail measured on the mast, from the top of
the boom when set at right angles to the mast, or the mainsail tack
whichever is the lowest, and the bottom of a permanent 25 mm band
of contrasting colour at the top of the mast above which the mainsail
shall not be hoisted. 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 head of the mainsail at
the peak or the head of the topsail if on board.
PY – The hoist of the mizzen sail measured as for P.
Runner – An item of running rigging from the mast below the masthead
in the vicinity of the forestay to the stern of the boat which may be
forward face of the mast tube to the extremity of the spinnaker pole,
adjusted while racing.
whisker pole or bowsprit, or the horizontal length from the forward
face of the mast tube at deck level to the spinnaker tack point on deck
Series Date – The year in which the first boat of the class or production projected vertically as necessary, whichever is the greatest.
series was launched.
Storm Jib – A headsail which complies with Special Regulations
SF – The foot length of the largest area spinnaker on board, measured
Paragraph 4.26: A storm jib of area not greater than 5% height of
between the clew points.
the foretriangle* squared, and luff maximum length 65% height of
the foretriangle. *Vertical height from sheerline abreast the mast to
SHW – The half width of the largest area spinnaker on board, measured
forestay attachment point on mast.
between the half leech points.

Variable Ballast – Water carried for the sole purpose of influencing
SLE – The leech length of the largest area spinnaker on board,
stability and/or trim and which may be varied in weight and/or moved
measured from the clew point to the head point.
while a boat is racing.
SLU – The luff length of the largest area spinnaker on board, measured
Wingspan – The maximum horizontal width in any transverse section of
from the tack point to the head point.
any wing, wings or bulb attached to any appendage.
x – The horizontal distance from the forward point of LWP to the lowest
SO – The horizontal distance from the aft point of LWP to the aft limit of
point on the stem at a tangent of 450 to the horizontal, in the condition
LOA, in the condition of Empty Weight (see Rule 22.0).
of Empty Weight (see Rule 22.0).
SPA – The maximum permitted spinnaker area.
y – The vertical distance above the waterplane of the aftmost point of the
hull on the centreline (in the case of a counter stern projected to the
STL (SPL) – The length of the longest spinnaker pole, whisker pole or
aft end of LOA) in the condition of Empty Weight (see Rule 22.0).
bowsprit measured on or near the centre line of the boat from the
8
45
IRC 09 Meas Defs P44-47_bs 45 1/12/08 09:12:38
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