Pembroke Haven Yacht Club

Hobbs Point, Pembroke Dock

PHYC policy on use of the Byron James Handicapping System (BJ)

Version 7.2



This policy and document is controlled by the PHYC sailing Captain and Sailing sub-committee.



The following is the essence of the club policy


  • We use BJ and agree to its determinations of handicaps from supplied data
  • As a norm, all boats are to submit specific data and pass on received determinations (certificates) to the sailing captain
  • Certificates to be updated as detailed below
  • Sailing captain to collect and file returned certificates from BJ. These state handicap number plus the submitted detailed data from which it was derived
  • These certificates to be made openly available to competitors for scrutiny in cases of dispute including club-club via sailing captains

BJ Handicapping system

This system is carried out by the Byron James organisation based on measurements supplied by owners of yachts and uses proprietary formulae to determine a boat’s theoretical hull speed and racing handicap number. It is a simple-to-operate and cost-effective system compared with alternative measurement-based systems, encouraging its widespread use in club racing. The BJ organisation issues an extensive but not necessarily complete list of boats that have been handicapped on its website. The list is updated every April and numbers refer to an average of the upper quartile of numbers for each class of boat, effectively meaning boats in race condition, that may have selective (non-Roller) high-tech sails, folding props, not carry cruising equipment etc .  Thus there is advantage for more cruising-oriented boats in obtaining a specific handicap for the boat as set up, and this is now(2023) mandatory for all club boats taking part in racing.

Registering BJ numbers

All boats taking part in club racing shall obtain individual BJ handicap numbers by submission of the boat’s detailed data to the BJ organisation. Although nominally free, a small ‘donation’ fee is normal to obtain results in a short timescale.  When submitting the form owners should request handicaps for no-spinnaker and no-pole racing so that BJ calculated figures can be used rather than the traditional 4% percentage allowance. This request can be made in the ‘notes:’ box at the end of the form.

In some circumstances a sailing captain may allow a boat to race under a BJ listed or assumed number if a very similar boat already has a listed handicap number, but this situation will only be temporary and for individual races such as regattas.


The update synchronisation will be set by Sailing Skippers meeting, at the start of a year. A global update was ordered for the 2023 season and it is expected that this will be repeated yearly.

Collation of numbers

The sailing captain shall obtain and file copies of emails from the BJ organisation advising owners of handicap numbers. These emails act as ‘certificates’ and also list the detailed data that was submitted and used to calculate the number. Ideally, and for all new submissions, a copy email should be requested to be sent to the sailing captain directly to maximise the certificate’s authenticity.

The sailing captain shall be responsible for loading and updating of numbers onto the club website  list of boats and handicap numbers, and by extension to any shared lists between clubs.

Review of numbers and data

The sailing captain shall make a brief ‘sanity check’ review of numbers and data to ensure no obvious mistakes have been made. In the case of disputes, the sailing captain may request and must be granted permission to physically check detailed measurements either him/herself or by engaging an independent measurer.

General Access to certificates

The certificates shall be held on an open-access basis so that any club skipper involved in racing can ask the sailing captain for a copy of any club boat’s certificate. This policy can be extended to competitors from other clubs via the clubs’ sailing captains subject to reciprocal rights.

Sailing under the BJ system

Sailing fleets can be split into divisions according to BJ number. Boats should normally race within their division. Variations of up to 2% may exceptionally be allowed by the sailing captain or day race officer if a good reason is given.

It should be noted that the BJ form now has several options for foresail roller-reefing, in particular one allowing use of smaller headsails to suit conditions. This should be selected if such use is planned, however, those having older certificates where the only options were roller reefing: yes/no must always use the certificate’s stated foresail.  Bending on of smaller headsails in strong wind conditions is then not allowed, with the exception of dedicated storm jibs having a maximum area of 25% foretriangle (TBC) .

White sails allowances are now calculated on an individual basis by the BJ organisation. It is our policy to use these wherever possible and for series racing, however a race officer may decide to give a greater allowance such as the traditional 4% if downwind conditions dictate, e.g. Tenby Passage Race or return from west end of the Haven with a westerly wind.

Sailing under white sails rating must be declared before the start sequence begins, either on an entry form or by VHF.

In races where divisions are organised with a specific division for white-sails only, BJ base numbers will be used for the division. This also applies to the Thorn Island Time Trial.