Measurement and Safety Guides

The priority of the 29er Class Association is to organise great racing on the water for everyone. But to help us ensure that racing is safe and fair, there are just a few rules and guidelines that all sailors must comply with. Remember that 29er class rules are “closed rules” so if anything is not specifically mentioned it is not permitted. Friendly info and guidance is freely available – please click here to contact our Class Measurer.

Please note, this page has been compiled in good faith, but no responsibility can be taken for any error and if there is any unintentional conflict with the Class Rules then, the Class Rules will apply.


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Safety Rules Mast Floats Measurement Modification



Buoyancy Aid

Class Rules (CR) state that all sailors must be equipped with an approved Buoyancy Aid (CR C.3.1) which is in good condition.

Trapeze Harness

When you are buying a new harness, please bear in mind that the 2021-2024 edition of the Racing Rules of Sailng state that from 1 January 2023, "a trapeze harness worn by the competitor on a trapeze shall be of the quick release variety complying with ISO10862 which allows the competitor to detach from the hook or other method of attachment at any time". 

29/12/2022 ADDITIONAL NOTE :  At this point, no trapeze quick release device meets the standards of ISO10862.  Consequently, the 29er International Class Association has amended the Class Rules to permit types which do not have a quick release device fitted.  Presumably in the event that some suitable devices are invented and become widely available this may change again in future.


Each competitor must carry a SOLAS Approved Whistle (CR C.3.1). These are essential if you get split from the fleet in fog, or as a way to quickly alert a safety boat if there is an emergency.  The International Class is very hot on this issue.  At the 2021 Worlds in Valencia, all the local chandleries ran out of SOLAS whistles which was a big hassle for competitors who found themselves without one.  Tie your whistle to your buoyancy aid and keep it in the front pocket.

Other Guidance

Many sailors carry a Folding Rescue Knife tied to their buoyancy aid and kept in the front pocket.  Rescue knives are yellow and have a rounded blade end so there is no risk of an accidental stab injury.  It is good practice to carry a knife like this on the water to help yourself or others should the need arise.  It is far better to carry a rescue knife and never use it, rather than one day finding that you, or a fellow sailor, is snagged but you have no way to deal with the problem.

If you look after it (and oil it occasionally) and only use it in the event of an emergency, you might only buy one rescue knife in your whole sailing career, so you might as well buy a good one!

Finally, never tie loops at the end of control lines.  They are a snagging risk.  Ideally use round plastic bobbles instead.


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Mast Floats

Q - During an event, can we add / remove a mast float?  Or do we have to sail all races either with or without a float?
A - Use of a mast float is optional in all UK events, sailors are allowed to use a mast float on one day of the event, but remove it for another day. Mast floats are not allowed at major international events.

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Quick FAQs on Equipment Rules

Q - Where can I get some quick info on 29er measurement?
A - Quick Measurement Checklist.


Q - Where is my boat’s measurement certificate?

A -

No written certification is required for 29ers.

All 29er hulls and equipment are supplied by licenced manufacturers and comply with Class Rules.  If you look closely you can see that the parts of each boat have a sticker or label with a unique number shown to identify it.  This includes, hull, spars, foils and sails.  At major events these numbers are noted down by the Race Committee to ensure that equipment used for racing is not changed without permission.   

Sometimes the serial number stickers can fall off. Don't worry the part will be given a new sticker at the next event where it is measured.


Q - What measurement is done at Grand Prix events?

A -

All racing sailors know that to keep racing fun and fair it is very important that everyone complies with the rules. Measurement compliance problems in the 29er fleet are very rare.

As a result of this, at our GP events, there is no formal measurement, sailors must not change any equipment used without permission of the Race Committee.  The Race Committee can, of course, inspect any boat at any time if it wants to.

In the event of non-compliance of any boat arriving at an event, the UK 29er Class Association will always make best endeavours to get every sailor racing on the water, but competitors need to make some effort in advance to check that their boat is compliant.


Q - What measurement is there for RYA Youth Nationals, 29er Nationals, Europeans and Worlds?

A -

At these events the measurement checks include:

  • Hull weight
  • Forestay length
  • Distance from mast to stem fitting
  • Equipment serial numbers noted 
  • Inspection of manufacturer’s fittings and sails to ensure not modified
  • Length of wire section of trapeze
  • Check to ensure no unauthorised equipment is being used

For reference, please see 2019 RYA Youth Champs Measurement info here and 2019 29er Worlds Measurement form here.

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29er Modifications

What modifications from the standard boat are allowed?

If you are thinking of modifying your boat or fittings, you should consult the Class Rules here.

The list below covers the most common questions:

  • Remember, if something isn't specifically mentioned in the class rules then it is not permitted.
  • Any block can be replaced with a block with same number of sheaves of similar or greater diameter.
  • The purchase on the jib sheet can be configured up to a maximum of 4:1.  This rule was changed in 2015.  Any arrangement of blocks or low friction rings / thimbles is permitted, but the maximum sheave diameter is 32mm.
  • 29er specific fittings, like spreaders, bow fitting, rudder fittings can only be replaced by the same model
  • Non-slip tape can be added to the deck
  • Thimbles, clip rings, balls etc may be added to control lines and shock cord take ups.


You can also: 

  • use wedges under the mast foot, but they can't be altered or removed during an event.
  • make some 'fittings' from a flexible material forward of the chainplates to retain spinnaker sheets on board.
  • add a compass or timing device bracket, GoPros are allowed as long as permitted by NOR & SIs.
  • use tape or bungee as long as the function of any fitting isn't changed.

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