Multihull Rating Rule
CSA Multihull Rating Rule belongs to the Caribbean Sailing
Association (CSA). This Rule shall not be used, copied or otherwise
distributed without the permission of the owner.
of the rule
- The CSA will appoint a Chief Measurer, Senior Measurers,
Measurers and Trainee Measurers to administer this rule. In order
to obtain a Rating under this Rule a yacht’s owner or captain can
contact one of the Measurers listed on the Caribbean Rule Website
WWW.CARIBBEAN-SAILING.COM and arrange to have the yacht measured.
In addition to measuring yachts Measurers provide the services
The intent of this Rule is to handicap fairly the broad variety of
multihull yachts which race within the Caribbean region. The rule
will compute a RATING for each yacht which is intended to be
representative of its true speed potential.
on Time Handicapping
- This Rule is a “Time on Time” rule – Each yachts RATING
will be converted to a TIME CORRECTION FACTOR (TCF) which will be
used to convert her Elapsed Time (ET) for the Race to a Corrected
Time (CT). (CT = ET x TCF). Hereinafter the terms “Rating” and
“TCF” shall mean one and the same thing.
standard TCF shall be applied, by default, to all races taking
place under normal Caribbean conditions. The
light TCF can be applied when the forecast conditions for a race
indicate that wind speeds are expected to be consistently below 12
knots for the expected duration of the race.
the Light TCF is to be applied, competitors should be advised no
later than 5 minutes before the warning signal for their class.
decision to apply the Light TCF will be taken at the sole
discresion of the Race Committee.
of the rule
- The measurements used, formulae and calculations are the property
of the CSA. The CSA may change these at any time.
- The rule is based on actual measurements. Formulae
used to calculate the rating will
be applied ‘across the board’ and not to a particular
individual yacht in isolation.
a Development Rule
- This rule is not a development rule and it is not anticipated
that owners or designers will deliberately seek to exploit the rule
so as to artificially reduce the yacht’s rating relative to her
true speed potential. Where this appears to have been done, the
Chief Measurer will take appropriate action to negate any unfair
- The CSA does not offer safety guidelines.
- This Rule is a ‘paperless rule’ and a yacht’s only official
TCF can be found on the latest computer database. Any paper issued
to the yacht is purely a measurement record.
The CSA Multihull Rule comprises an “in the water” measurement
part as well as the requirement for a certified displacement.
Inspection of the underwater appendages may be required, especially
in the case of foils that are designed to provide vertical lift.
- Any regatta using the CSA RULE may, in consultation with the CSA
Chief Measurer (CM), appoint and bear the cost of a CSA Measurer as
Regatta Measurer to
serve on the Technical Committee. Duties
the Organising Authority and Race Committee on class assignment.
ratings of all entered boats and notify the owner, organizers and the
Protest Committee of any errors found.
c) Be the
“authority responsible” referred to in RRS 64.3 and perform any
services required under this article from such an authority, provided
that the CM has issued the necessary permission for the Regatta
Measurer to perform this role.
errors found as permitted under the CSA RULE and as agreed by the
and submit a detailed Measurer’s Report on the regatta.
other duties requested by the Organisers that are appropriate to be
done by a Regatta Measurer.
Ratings during Regatta
is satisfied that there is a technical
error (i.e. typographical, calculation, measuring error, incorrect
TCF /sail combination, etc.) in a boat’s current rating at any time
during the regatta, the Technical
shall notify the relevant authorities including the protest
committee. If the protest committee is satisfied that the rating is
in error, the Measurer shall make the necessary corrections and the
scoring shall be adjusted to the new TCF for all races in the regatta
including those already sailed.
rating protest is submitted to the protest committee that committee
will be responsible to ensure that both the protesting and the
protested yachts deposit measurement fees as described under CSA Rule
3.1 (see below). RRS 64.3(d) shall be used to determine which party
will pay any measurement fees incurred and which party shall have the
measurement fee refunded.
result of a protest on rating, or as a requirement from the race
committee a yacht is re-measured to confirm her rating handicap, the
following tolerances to confirm her TCF shall apply.
protest is solely in relation to the use of incorrect sails, then
only the sails need to be measured. If as a result of this
measurement the TCF of the yacht changes by ‘more’ than +/-
0.001 then the protest is considered to be upheld and then yacht’s
TCF will be adjusted accordingly.
protest is of a more general nature and the entire yacht requires to
be re-measured then the protest shall be considered to be upheld if
the yacht’s TCF differs by ‘more’ than +/- 0.003 from the
current TCF and the database will record the new rating.
Chief Measurer is the final authority for interpretation of this
resolving disputes the CM will be guided by the intention of the rule
(to provide a fair TCF as stated in para A1.2 above) rather than by
the precise wording of any clause or statement. This authority can be
delegated to a Regatta Measurer or other senior Measurer if
yacht, arriving at a regatta to race, cannot be given a measurement
rating because of some abnormality in its dimensions which results in
the calculated rating being inapplicable, or which has essential
equipment which is not allowed under the rule, the matter shall be
referred to the Regatta Measurer (if there is no regatta Measurer
this shall be referred to the Chief Measurer). The RM/CM shall use
his best efforts to arrive at a fair rating for the yacht and may
suggest to the regatta organizer that this yacht be given a
provisional rating (for this regatta only) to allow it to race.
The RM/CM shall have the authority to alter the rating of the yacht
during the regatta if, in his subsequent opinion, the initial rating
allocated does not truly represent the speed of the yacht.
common classes may be given standarised hull and rig dimensions which
are recorded in the database as an average of many measurements for
that particular type of yacht. In this case only the sails, factors,
and miscellaneous information, need to be recorded uniquely in the
database, the hull and rig dimensions being the standards. If the
Measurer suspects that the boat may not be a substantially standard
production version, (for example if it has been modified, or stripped
out, etc.) he shall measure the boat in the normal way and it will
race with the TCF for that specific yacht rather than the TCF
assigned to the class.
shall determine which designs may have standard measurements. The
CM’s approval is required for all boats with standard dimensions.
From time to time the standard measurements may be modified as more
information is collected.
Design Class Rating
classes may be designated as ”one-design” and each yacht in the
class can be given the same CSA rating after it is determined that
the yacht is ‘Class Legal’ by a Measurer who is qualified to
determine this for that class of yacht. The CM shall determine which
Measurers can issue one design certificates and the TCF for each
Organisers have the right to stipulate minimum sizes of yacht which
will be accepted into the class and regatta as a whole. Establishment
and control of these minimums is outside the scope of this rule.
Measurer shall advise on preparing the yacht to be measured, advise
on how to obtain an optimal rating, measure the yacht and enter the
data into the rating program. This program will compute the rating
of the yacht and also compute several TCFs for varying sail
combinations. The Measurer shall charge a fee for this service.
measurement fee is made up of two parts: (a) a fee for the
administration of this Rule and, (b) a fee to reimburse the measure
for the service provided. These fees are charged based on the
overall length of the yacht. Fees will be collected as specified by
the CSA from time to time and may be collected by the individual
Measurer who Measures the yacht and who will pass on the
administrative portion of the fee to the CSA.
for year 2017
(a) US$ 2
per ft t plus (b) US$ 2.00
(a) US$ 2.00
per ft plus (b) Measurer’s hourly rate.
involving no measurement (a) US$ 2.00
per ft (b) US$ 25 flat rate.
Measurer’s hourly rate may differ according to which island he/she
is based in.
measurements taken for the yacht shall be entered in the CSA
Multihull Rating Program. The TCFs shown by this software is the
current Rating for the yacht. A yacht may only have one current
and Measurement Validation
for one complete calendar year Jan/01 – Dec/31 (Note – Yachts
which carry out a first measurement or a change update after
01/Dec of any year will consider to have been measured / certified
in the next full calendar year), unless this rating becomes
invalid as indicated below.
for five calendar years from first measurement – including the
year of measurement - unless they become invalid as detailed in
3.3.3 below. Invalid measurements result in an invalid rating.
become invalid when
is sold to a new owner
calendar years elapse, including the year of first measurement
is significantly modified since last measured
acquires new sails
If the CM
determines that a Rating is invalid
Rating Rule is changed to require different measurements or different
ways of measuring
When a Rating becomes invalid the owner or agent shall request a
re-measurement of the yacht. When requested to do this a Measurer
shall carry out such checks or re-measurement as necessary and
shall update the database as appropriate.
to update a rating a Measurer shall carry out whatever checks – up
to and including a full re-measurement – that he/she think are
appropriate to comply with 1.2. There is an obligation on the yacht’s
owner / captain to point out any modifications made or other reason
why the boat’s rating should not be automatically updated.
Deliberate failure to do so may result in the yacht’s Rating being
invalidated by the CM.
rating may be updated at any time to accommodate changes made to the
yacht, but its rating shall not be updated more than three times in a
calendar year without approval from the CM.
Changes Prior to an Event
several alternate TCF’s (for different sail combinations) for each
rated yacht. A yacht may elect to race with any one of these TCF’s,
but must declare which TCF/sail combination it intends to use by the
deadline set by the Regatta Organizers. The TCF elected to be used
cannot then be changed during that specific regatta.
request to alter a rating immediately prior to a regatta, after that
yacht’s initial registration but before close of registration,
shall be put to the RM/CM who shall adjudicate on this matter. Late
measurement changes are to be discouraged.
re-measurement of a yacht shall be undertaken every 5 years or if the
current measurements become invalid for any reason (See .3.4 and .3.5
also be done at the request of the CM if he/she suspects that the
rating may be incorrect, It may also be done at the request of a
protest committee as a result of a valid protest.
of the yacht may not request re-measurement by a different Measurer
in a different territory within the existing rating’s measurements
validity period (5 years) without specific reason being given and the
specific approval of the CM obtained. (i.e. ‘shopping around’
for best measurement is not allowed.)
ratings may be issued only for a single regatta and only and as a
last resort. The Measurer must be confident that the rating so
issued will stand up to a measurement protest. The rating must be
clearly marked as “TEMPORARY” in the database and should include
the circumstances requiring its issue in the notes. A Temporary
Rating cannot be updated without a full measurement of the yacht.
racing under the CSA Multihull Rule may use power assisted winches
and may use power activated auto steering systems, if they wish.
This changes ISAF RRS 52.
– Measurer Responsibilities
OWNER shall be responsible for presenting his yacht for
measurement as specified in 3.13 and in a location (Note – a
location at a dock is normally preferable) where the water is
sufficiently calm to ensure an accurate measurement. The Owner
(or his agent) must be in attendance to assist as necessary. The
Owner must ensure that there is a suitable dinghy available. The
Owner must make available all sails requiring measurement – or
provide appropriate certified data for these sails (from a
reputable sailmaker or another internationally recognized
MEASURER shall ensure the yacht is in a proper condition for
measurement as specified below. The yacht is to be measured Empty
so the Measurer shall personally check the whole boat from stem to
stern including sounding all tanks and bilges to ensure the
conditions for Empty are adhered to. Shortcomings shall be
brought to the attention of the owner who shall remove, relocate,
or fix all items as required by the Measurer in accordance with
of a Yacht for Measurement
- A yacht will be presented for measuring in an empty state as
items needed for racing may be left on board, including racing
sails, sheets and halyards and racing anchor. In addition, all
normal furnishings may be left in place, including drawers, doors,
tables, cabin soles and bunk mattresses.
other items such as food, drinks, stores, tools, safety equipment,
additional lines and personal belongings must be removed and all
bilges must be empty.
tanks will be empty, except for the fuel tank, which may contain a
measured amount of fuel.
underwater surfaces must be clean and free of marine growth.
- The following information must be readily available for the
Name and Address
(or ship’s) Email address
Class or Type
Draft – from ship’s plans or other recognized data sheet
Draft – for yacht equipped with daggerboards
drawings showing underwater profile of yacht and any foils that may
/ drive – number and type
any existing rating certificates, from any recognized rating
authority, including the CSA.
- To ensure accuracy of measurement, yachts shall move into a
sheltered location as designated by the Measurer with minimal wind
and water disturbance (and a clear space all around the yacht of
- The Owner, Captain, or their representative shall be in
attendance to give assistance as needed.
- The Owner, Captain or their representative shall provide a small
tender or dinghy for the Measurer to take the Freeboard and
and mizzen measurement - the
owner must have available the main and mizzen sails that he
intends to use for racing.
- the Owner must have available the largest area headsail he
proposes to use for racing. He must be aware that he cannot race
with a larger headsail than that declared. If he has stamped and
signed sails from a previous measurement these markings must be
available for scrutiny.
– the Owner must have available all spinnakers and screachers
that he intends to use for racing.
– sails will be measured in accordance with the current
measurer's guidelines. If a measurement certificate from a
recogised sail loft or other institution exists, these
measurements may be used in place of physical measurements where
– the owner must provide a recent weight certificate for his
yacht. The certificate must be prepared from measurements taken
from a direct single point load cell or from multiple load cells
on a travel lift that have been calibrated to eliminate the
horizontal load component. The yacht must be weighed in measuring
– in some cases, where it is impractical to weigh the yacht, a
specified displacement from the manufacturer may be allowed in
place of the measured displacement. The lightest published
displacement for the particular model will be used.
– Measurements defined as follows will be taken in order to
calculate a particular yacht’s rating:
displacement of boat
displacement of boat
overhang – 0 for plumb or reverse bow
freeboard – enter 1 for plumb or reverse bow
overhang – 0 unless aft most point occurs more than 2% of LOA
freeboard – enter 1 unless aft most point occurs more than 2%
of LOA above waterline
correction factor - none = 1, One fold = 0.98, One fixed = 0.97,
Two Fold = 0.975, Two fixed = 0.964
to underside of hull or fixed keel if present
type – Catamaran = C, Trimaran = T
type – None=N, Standard=S, Asymmetric=A, C-Board=C, L or
2, 3, 4 Board /Foil 1, 2, 3, 4 maximum exposed vertical length
2, 3, 4 Board /Foil 1, 2, 3, 4 maximum exposed horizontal length
2, 3, 4 Board/Foil 1, 2, 3, 4 maximum cord
control – Rotating = R, Fixed = F
control – Canting = C, fixed = F
of rotating mast
of rotating mizzen mast
distance between the top of the mainsail hoist and the clew
+/- Vertical distance of mainsail clew above or below tack
outhaul distance perpendicular to mast
declared area (for info only, not to be used in rating
/ 2nd main
+/- Vertical distance of mizzen clew below or above tack
outhaul distance perpendicular to mast
declared area (for info only, not to be used in rating
(Most forward sail flown from a fixed stay)
distance from clew to luff
headsail area (for info only, not to be used in rating
of spinnaker luff
of spinnaker leach
of spinnaker foot
between mid points of spinnaker luff
spinnaker area (for info only, not to be used in rating
between mid points of screacher
screacher area (for info only, not to be used in rating