We reserve the right to check submitted measurements against our database of yachts and, where significant differences in
hull dimensions exist, to substitute standard dimensions - unless suitable evidence in support of those submitted is available.
Remember that the principle of VPRS is to rate a boat on its performance potential. Anything that alters this should be reflected
in the measurements and hence the calculated rating. The idea is not to look for, or to exploit, loopholes in the measurement definitions.
This guide (below, and in PDF format, top right) describes the data and measurements required for a rating certificate. VPRS employs standard
Universal Measurement System (UMS) data, abbreviations and methods wherever possible, so data is interchangeable with other rating systems
including IRC and ORC. More information is available in World Sailing's Equipment Rules
of Sailing (ERS).
|
|
Applicability
|
|
The issue of a VPRS rating or certificate shall not constitute any recommendation or warranty and shall not be used to judge
the suitability of a vessel, as rated or otherwise, for operation in any area or in any conditions. The sole purpose of a
VPRS rating is to modify elapsed times recorded in yacht races.
|
|
VPRS data sources and accuracy
|
|
Linear dimensions should be taken to the nearest centimetre.
Weights should be given to the nearest 10 kilograms.
When completing a rating application form, or when amending a revalidation form, you must indicate the
source
of each measurement by choosing one of the following five codes:
|
|
|
|
|
|
A = Authenticated |
measurements made by the rating office or an appointed club measurer,
or taken from an endorsed IRC certificate for the vessel;
or provided by an approved sailmaker (see below).
|
|
|
|
C = Calculated |
for measurements which are directly calculated from others;
(only applies to waterline length on an application or revalidation form).
|
|
|
|
O = Owner measured |
for measurements that you have made. |
|
|
|
P = Published |
measurements taken from published sources, including specifications from designers and manufacturers.
|
|
|
|
S = Sister ship |
Hull measurements which have either been made on,
or taken from authenticated data on a VPRS certificate of;
or taken from an endorsed IRC certificate of;
a vessel of exactly the same type. May not be used for sails.
|
|
|
Data on VPRS rating certificates and revalidation forms may also have the following qualifiers:
|
|
|
|
|
D = Database derived
system use only
|
for data derived from authenticated weights or measurements held against sister ships already
in the VPRS database. |
|
|
|
E = Estimated
system use only
|
for estimates calculated by internal system routines.
Do not estimate any measurements yourself ... if a measurement is not available from any of the above sources,
mark the field with an 'X' on the application form. |
|
|
|
Weight
|
|
Weight is one of the fundamental factors affecting boat performance; accurate weights help to ensure an accurate rating. However, unlike
other measurements, it is hard to check the weight of a competitor. Hence, in the interest of fairness, we generally accept only
two sources of weight data: 'A' and 'P'. Weights verified by weighing are recorded as 'A' and are the first
preference. If a boat has not been weighed we have to rely on published sources, which can be referenced by all users.
However we acknowledge that published weights are often wrong - even those published by manufacturers.
Modern production yachts are usually quite close to their designed weight, but older boats are often (although not always) heavier. Hence it is
likely to be in your interest to get your boat weighed.
We can make an exception to the above rule when we have a number of boats of the same type, of which more than one have been weighed. If the weighed boats
show a consistent deviation from the published weight, we can issue a weight classified as 'D' (database derived). The value will be calculated from
authenticated sister-ship data, both current and expired. The aim is to record a weight which is highly unlikely to exceed that which would have been
obtained by weighing.
For boats with no published weight data, we can estimate something workable from the hull dimensions and an end-on photograph of the hull which shows
the shape of the midship section.
|
|
Please don't hesitate to contact us for advice
- if there is anything that you are unsure about. Weighing yachts is time-consuming and can be costly, so it's important to get a good result.
Ensure that during lifting, insurances for both the vessel and public liability are in place.
When using a load cell to weigh a yacht, please note the following requirements:
|
|
the vessel must be in the 'empty weight' condition - see below
the load cell must have a valid certificate of calibration, and a copy acquired
the load cell calibration error should not exceed +/-0.5% at the measurement point
the load cell should be able to resolve changes of +/-0.25% at the measurement point
if either load-cell tolerance is not met, any measurement error must not exceed 0.75%
the yacht must be hanging freely from a single-point lift
the yacht must be at rest
lifting equipment engines should be shut down
authenticated weights can only be recorded by a VPRS measurer
|
|
|
Weighing can only be undertaken in calm weather. Wind speeds in excess of 10 knots are likely to introduce an offset error
on account of windage. Gusting winds will make the readings unstable.
The aim is to determine the boat weight to within 1%, taking into account errors arising from the conditions as well as
the accumulated load-cell errors.
Finally, remember that having the boat prepared in the 'empty weight' condition gives an ideal opportunity to
measure the bow, stern and topside overhangs, the transom height and the mean freeboard - refer to the measurement guide below.
In addition it is also possible to take a measurement, whilst alongside, which is needed to establish the draught.
The PDF link above captures all the information required for weighing - on a single sheet of A4.
|
|
The following sailmakers are recognised as measuring sails in accordance with this guide:
|
|
Banks Sails
Batt Sails
Dolphin Sails
Doyle Sails
Edge Sails
Elvestrom Sails
Flew Sails
Goacher Sails
HD Sails
Kemp Sails
North Sails
OneSails GBR
Pinnell & Bax
Sail Shape
Sanders Sails
Saturn Sails
Ullman Sails
Ultimate Sails
Westaway Sails
|
|
|
The measurement definitions provided below are arranged in the same groupings and order in which they appear
on an application or revalidation form. Essential* and conditional(*) measurements are identified
at the end of each section. There are also PDF diagrams to illustrate many of the measurements; for convenience
these open in a new window.
Yacht - identification
Most of the information at the top of the application form is self-explanatory. The following items sometimes benefit from clarification.
Club(s) / event(s) Used to control listing on the VPRS web site, so please state which club(s) or event(s)
you plan to race with, whether or not you are a member.
Rig type State the type of mainsail/rig - usually Bermudian or gaff - and whether sloop, ketch, yawl
or schooner, noting in addition if the yacht is a cutter. For example, 'Bermudian Sloop', 'Gaff Ketch', 'Bermudian yawl cutter'.
Design If possible state both the builder and model and any additional information that helps to
differentiate between models with similar names. For example Laser 28, Beneteau First 29, Dehler 36 (00).
Series date The year when the design was first built. So, for example, the Dehler 36 CWS has a series date
of 1988 whereas the Dehler 36 (00) has a series date of 2000.
Build date The year when the yacht to be rated was built.
Hull
Hull length (LH)* The length of the hull excluding the bowsprit and other rigging, stem
and stern fittings, railings, rubbing strakes or any overhanging rudder and rudder hangings.
Bow overhang (BO)* The horizontal distance from the point where the stem cuts the water to the forward limit
of the hull length, with the boat in the empty weight condition.
Stern overhang (SO)* The horizontal distance from the point where the hull meets the water, ignoring any skeg,
to the aft limit of the hull length, with the boat in the empty weight condition. Must either be measured or determined from
the hull length, the bow overhang and the waterline length.
Waterline length (LWL)* The horizontal distance between the point where the stem cuts the water and the point
where the hull meets the water at the stern, ignoring any skeg, with the boat in the empty weight condition. Usually determined by subtracting
the bow and stern overhangs from the hull length.
Stern height (Y)* The vertical height from the surface of the water to the aft-most point on the hull
moulding, with the boat in the empty weight condition. If the aft-most point is underwater, record a stern height of zero. For yachts with
an outward-sloping transom which is out of the water, first drop a vertical line from the aft-most point of the hull. Then project the underside
of the hull and mark the point where it intersects with the vertical line. Measure the vertical height from the water to this point.
Beam (MB)* The maximum width of the hull, measured horizontally with the boat upright and excluding rubbing
strakes, toe rails or other fittings. For a vessel with tumble-home, this will need to be taken between points on the topsides.
Topside overhang (TSO) The horizontal distance from the point where the side of the hull meets the water, to a
point vertically below the point of maximum beam (see above) with the boat upright in the empty weight condition. Best taken as an average of port
and starboard measurements to reduce the error arising from any list. If not submitted, topside overhang will be estimated as a proportion of the
beam. There is a drawing to illustrate this measurement.
Freeboard (FBI) The vertical height of the hull topsides, adjacent to the mast, measured from the surface of
the water to the sheer line (the edge of the deck) with the boat in the empty weight condition. Where any bulwark is a fair continuation of the line
of the topsides, the top point shall be taken at the top of the bulwark. If not submitted, the freeboard will be estimated using a formula
based upon the hull length.
Draught (T)* The maximum depth below the surface, including the keel, with the boat in the empty weight
condition. If the boat has a lifting keel then the draught should be given with the keel fully down.
Empty weight (EW)* The empty weight condition is as follows:
Vessel to be fully rigged (spars, standing rigging, running backstays) and dry: the bilges, any other sumps, any raised sections
of the hull interior structure, and any sinks and toilets, must be empty.
In addition, the empty weight ...
includes: all halyards, main and mizzen sheets, spinnaker pole, bow sprit, engine (installed or on board), batteries,
fixed internal ballast and wash boards. Also includes all permanent fixtures and fittings for the accommodation - which must be in place.
Where any of these items are on board when meeting the empty weight condition, they must also be on board when racing.
excludes: all sails, headsail sheets and guys, spare rigging, the contents of all tanks (including ballast tanks),
anchors and cables, tools and spares. Additionally, all removable equipment (gas bottles, cooking and catering utensils, safety equipment
including life rafts), all clothing and bedding, and personal effects, must be removed from the vessel.
Tankage note: where the capacity is stated, or can be readily determined, tanks may instead be pressed up. In cases where it is
straightforward to determine the volume of the contents, no action need be taken.
The additional weights will be calculated with reference to capacities and specific gravities, and the total will be
subtracted from the recorded weight.
Fixed Ballast weight (KW) The weight of the ballast keel and any internal ballast carried. Distinguish between the two
if possible. If not submitted the ballast weight will be estimated as a standard percentage of the empty weight.
Moveable ballast If the yacht has moveable ballast such as water ballast tanks or a canting keel or both, then this is noted here;
choose either 'None', 'Water', 'Canting keel' or 'Ctg keel & Water'. Please contact the rating office so that the appropriate measurements can be determined.
The additional righting moment available as the vessel heels will be calculated.
Essential hull data: hull length, bow overhang, stern overhang, waterline length, stern height, beam, draught, empty weight.
Appendages & propeller
Keel type* Eight characters (comprising 4 pairs) which specify the form and material of the keel.
The twin-character codes are chosen in sequence from the following four categories: keel planforms, keel sections,
keel materials & 'other discriminating features'. The last category allows lifting/swing fins and additional ballast to be accounted for.
An example: Hustler 35 ... T2P2F5N1; for which keel planform = T2, keel section = P2, keel material = F5 and 'other discriminating features' = N1.
Some others: Contention 33 ... Z2P1L1N1; Beneteau First 260 Spirit ... Z4P1R1S2; Beneteau First 285 ... S1S1R3S1; Elan 410 ... H2H5R2N1; Hanse 320 ... R2R1R2N1.
You will need to refer to the Keel classification drawings
and make a selection from each of the four categories as illustrated above.
Swing fin with Bilge keels: Keel type/depth/chord should describe the swing fin; additional depth & chord measurements will then be needed for the bilge keels.
Note: bilge keel depth should be measured parallel to the keel surface.
Canting keel (& Dagger boards): Keel type/depth/chord should describe the canting keel; additional depth & chord measurements will then be
needed for any dagger boards. Note: dagger board depth should be measured parallel to the dagger board surface. Also see 'Moveable ballast' above.
If your keel configuration cannot be adequately captured in this way, then it may be necessary to record it as an individual design; please contact the rating office.
Keel depth (KD) The vertical distance between the bottom of the hull (canoe body) at its lowest point and the bottom
of the keel at its lowest point. Note that the vertical measurements required are frequently at different fore and aft positions; please
refer to the pdf diagrams. It will almost always be necessary to estimate where the lowest point of the hull would be without the keel.
If not submitted the keel depth will be estimated using a formula which includes the waterline length and beam, and the displacement.
Bilge keels: The keel depth should be measured parallel to the keel surface. Also required is the keel contribution to the draught: this is the vertical
distance between the lowest part of the canoe body and a horizontal plane which intersects the bottoms of the keels (ie height of canoe body above keel blocks).
Keel chord (KC) The horizontal distance from the leading edge of the keel to the trailing edge, measured at half the
keel depth; please refer to diagram. Long keeled yachts with keel-hung rudders should exclude the rudder. If not submitted the keel chord
will be estimated using a formula which includes the keel depth and the sail area.
Rudder type* Description of the rudder(s) including number, form/mounting and whether the rudder is fixed or lifting.
For example, 'spade', 'twin spade', 'skeg hung', 'keel hung', 'transom hung', 'twin transom hung'. The description submitted
will be converted to one of a number of standard phrases on the certificate.
Rudder depth (RD) For rudders that are usually wholly submerged, the vertical distance from the top of the rudder
(and skeg, if any) to its lowest point. For rudders that are partly out of the water (eg transom-hung rudders),
the vertical distance from the waterline to the lowest point of the rudder (and skeg, if any).
Twin rudders: These are usually splayed. Simply imagine that the boat is heeled so that one of the rudders is vertical in the transverse plane, and
measure as described above.
Rudder chord (RC) The horizontal distance from the leading edge of the rudder (and skeg, if any) to the trailing edge,
measured at half the rudder depth. For keel-hung rudders measure the rudder blade only.
Propeller type* Choose either 'None', 'Fixed', 'Feathering' or 'Folding'. Vessels with fully retractable stern gear or
outboard engines that are stowed with the propeller out of the water when sailing should choose 'None'.
Propeller blades (PRN) The number of blades on the propeller.
Propeller diameter (PRD) The diameter of the circle described by the blade tips. For folding or feathering propellers, this
measurement should be given with the blades in the unfolded, working position.
Essential appendage and propeller data: keel type, rudder type, propeller type.
Rig
Spar material The principal material used for the spars, choose either 'Aluminium alloy', 'Timber' or 'Carbon fibre'.
Forestay length (FL)* The length measured from the point at which the forestay is attached to the deck (or bowsprit) and
to the point at which the forestay attaches to the mast, or to the point at which any upwind headsail is attached to the mast, if higher.
Foretriangle base (J)* The horizontal distance from the front face of the mast to the point at which the forestay attaches to the deck (or
bowsprit), or to the point at which any upwind headsail is tacked, if further forward.
Flying headsail tack length (FHTL)* The length from the forward face of the mast to the point where the sail is tacked, on the centreline,
either to the deck or a bow sprit.
Spinnaker pole length (SPL)* The length of the longest spinnaker pole measured on the centre line of the boat from the forward face of the
mast to the extremity of the pole.
Main hoist (P)* The distance from the top of the boom to the top of the main halyard shackle pin, when fully hoisted. Or, from the top of
the boom to the bottom of a fixed 25mm band of contrasting colour towards the top of the mast. The head of the mainsail may not be hoisted above this band. For a gaff rig, the
hoist is measured vertically from the boom to the peak of the mainsail. If a gaff topsail is used, measure to the head of the topsail.
Main outhaul (E)* The distance along the boom from the aft face of the mast to the aftmost face of the clew outhaul shackle pin, when
hauled all the way to the end of the boom. Or, the distance from the aft face of the mast to the inside of a fixed 25mm band of contrasting colour applied towards the end of
the boom. The mainsail clew may not be hauled beyond the band.
Boom above sheer (BAS) The vertical height from the sheer line to the top of the boom, just aft of the mast. If not submitted BAS will
be estimated as a proportion of the main hoist (P). To measure BAS, tie a piece of string between the guard rails just aft of the mast. Measure from the string to the sheer
line (where the deck meets the topsides - ignore the toe rail) on both sides. Take the average of the two measurements. Now measure from the string to the top of the boom.
Add this to the average you just calculated. You now have BAS.
Mizzen hoist (PY)* As for the Main Hoist (see Rig below) but on the mizzen mast.
Mizzen foot (EY)* As for the Main Foot (see Rig below) but on the mizzen boom.
Essential rig measurements: Forestay length, foretriangle base, flying headsail tack length, spinnaker pole length, main hoist, main
outhaul, mizzen hoist, mizzen outhaul.
Mainsail
1/2 width (MHW) The shortest distance between the half leech point and the luff, bridging any hollows in the leech. If not
submitted the half width will be assumed to include a roach and will be estimated from the mainsail foot.
3/4 width (MTW) The shortest distance between the three-quarter leech point and the luff, bridging any hollows in the
leech. If not submitted the three-quarter width will be assumed to include a roach and will be estimated from the mainsail foot.
Upper width (MUW) The shortest distance between the seven-eighth leech point and the luff, bridging any hollows in the leech. If
not submitted the upper width will be assumed to include a roach and will be estimated from the mainsail foot.
Sail construction State either 'Laminated' or 'Woven'. If any mainsail to be set whilst racing is of laminated construction then
choose 'Laminated', otherwise choose 'Woven'. If not submitted, then 'Laminated' will be assumed.
Mainsail reefing State the reefing method, one of 'Slab', 'Roller', 'In-mast' or 'In-boom'.
If not submitted, 'Slab' will be assumed.
Essential mainsail measurements: None.
Mizzen staysail
Staysail luff length (LLY)* The longest luff length of any mizzen staysail, measured in the same way as the upwind headsail luff length.
Staysail luff perpendicular (LPY)* The longest luff perpendicular of any mizzen staysail, measured in the same way as the upwind headsail luff perpendicular.
Essential mizzen staysail measurements: All.
Upwind headsail
An sail set forward of the foremost mast that can be used to sail close to the apparent wind. It may be
attached to a stay or have a loose luff. The working area of the largest sail used for this purpose should be measured with
reference to the shape of the sail when it is set. For cutters, only the luff length and luff perpendicular are required.
Luff length (HLU)* The shortest distance from head to tack when stretched sufficiently to remove creases - placing
one or two flakes along the luff will help considerably. For a cutter, the luff of the sail set on the foremost forestay should be measured.
Luff perpendicular (HLP)* The shortest distance from the clew to the luff or part of the sail that behaves as the luff. For a cutter, the
luff perpendicular is measured as the shortest distance from the foremost forestay to the aftmost clew of the headsails when set on the centre-line of the boat.
1/2 width (HHW)(*) The shortest distance between the half leech point and the luff, bridging any hollows in the leech
of the sail. If not submitted the half width will be estimated from the luff perpendicular.
3/4 width(HTW)(*) The shortest distance between the three-quarter leech point and the luff, bridging any
hollows in the leech of the sail. If not submitted the three-quarter width will be estimated from the luff perpendicular.
Foot height (HFH) When sailing close-hauled, the height of the foot (midway between tack and clew) above the deck.
If it touches the deck then record the measurement as 0m. Where not submitted a value calculated from the other upwind headsail dimensions, applying a degree of
performance advantage, will be used.
Sail construction State either 'Laminated' or 'Woven'.
If any upwind headsail to be set whilst racing is of laminated construction then choose 'Laminated', otherwise choose 'Woven'.
If not submitted, then 'Laminated' will be assumed.
Reefing State the primary reefing method, either 'Change sail' or 'Roller'.
When stating 'Roller' then, with the exception of a storm jib, other upwind headsails may only be used where the
area does not exceed 67% of the rated headsail area; we can check this for you. If not submitted, then 'Change sail' will be assumed.
Essential upwind headsail measurements: luff length and luff perpendicular. For boats where the
luff perpendicular is less than 110% of the foretriangle base, the half width and three-quarter width must also be submitted.
Downwind headsails
Sails set forward of the foremost mast from three corners only. They may be symmetrical or asymmetric. Sails tacked to a spinnaker pole are described as spinnakers.
Sails tacked only on the centreline (whether a fixed bow sprit or the deck) shall be described as flying headsails. Boats may carry either or both. The working area
of the largest spinnaker and largest flying headsail shall be stated, measured with reference to the shapes of the sails when set. Flying headsails with a wire luff
that can be tensioned in the same way as the forestay must be rated as upwind headsails.
Flying Headsail Luff length(*) (FHLU) The luff length of the largest flying headsail, measured with the sail pulled taught from
the tack to the head.
Flying Headsail Leech length(*) (FHLE) The leech length of the largest flying headsail, measured with the sail pulled taught from
the clew to the head.
Flying Headsail 1/2 width(*) (FHHW) The distance between the half leech and half luff points, with the sail held taught between the two.
Flying Headsail Foot width(*) (FHFL) The distance between the tack and clew, with the sail held taught between them.
Spinnaker Luff length(*) (SLU) The luff length of the largest spinnaker, measured with the sail pulled taught from
the tack to the head. For a symmetrical sail the designation of leech and luff is arbitrary, so long as both are measured.
Spinnaker Leech length(*) (SLE) The leech length of the largest spinnaker, measured with the sail pulled taught from
the clew to the head. For a symmetrical sail the designation of leech and luff is arbitrary, so long as both are measured.
Spinnaker 1/2 width(*) (SHW) The distance between the half leech and half luff points, with the sail held taught between the two.
Spinnaker Foot width(*) (FHFL) The distance between the tack and clew, with the sail held taught between them.
Essential downwind headsail measurements: luff length, leech length, half width and foot width for both the largest flying headsail
AND the largest spinnaker.
