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Welcome to the Sigma 33OOD

The Sigma 33 OOD (Offshore One Design) was designed by David Thomas, and introduced in 1978, becoming an immediate success. The original Sigma 33 OOD has a deep fin keel and a fractional rig.

From 1981 onwards a 'detuned' cruising version was also produced, with less sail area on a shorter masthead rig, and a shallower but heavier fin keel. Although still moderately fast yachts, and excellent boats, these were never as popular as the original OOD versions, which were equally capable as cruising and racing yachts.

About 410 of the two types were built, until production ended in the early 1990s. 'Practical Boat Owner' describe the design as ".... an excellent fast cruiser", and 'Sailing Today' said the design was ".... fast, stable, and of course, a pleasure to sail". Despite being an old design, Sigma 33s still turn up doing well in almost every major offshore event's race results, and have made long passages as pure cruisers - at least one has circumnavigated and several have crossed the Atlantic. Their heavy weather ability was proved early on as two survived the 1979 Fastnet race.

The class is still very active as a one design class with annual Class Championships around the UK and Ireland, as well as one design starts at the Scottish Series, Dun Laoghaire Regatta and Cowes. It is also very competitive under IRC with a OOD class handicap of just 0.912. 

The Fleets

There are active Sigma 33 fleets in:

  • Solent

  • South West 

  • North East

  • Clyde (Scotland)

  • Belfast Lough (Northern Ireland)

  • Pwheli and Aberscoch (Wales)

  • Dublin Bay and Irish Sea

  • Holland (International)

Class Championships

Held annually, a chance for Sigma 33s  across the world to compete against each other for the Class Championship Trophy. The Class Championships/Nationals are held annually at a different location each year :

 Bangor 2022, Dun Laoghaire 2021, Dartmouth 2019, Helensburgh 2018, Bangor 2016, Cowes 2015, Abersoch 2014, Helensburgh 2013, Dublin Bay (2012), Bangor (2011), Cowes (2010), Tarbert (2009), Dublin Bay (2008), Yarmouth, Isle of Wight (2007), Belfast (2006), Torquay (2005), Cork (2004), Dublin Bay (2003), Clyde (2002), Falmouth (2001), Cork (2000).


The AGM is hosted during the Class Championships with the chance to elect or join the new committee, discuss any issues and agree any proposed rule changes.

Class Measurement Rules

The latest 2022 Class Measurement Rules are available in Documents

The Sigma 33 OOD - about the boat

• Designed by David Thomas, well-known for cruiser / racer designs such as Sonata, Impala, Sigma 33 and 38, as well as the Hunter 707.

• The original concept was to design a 35 footer to compete for acceptance at the Royal Ocean Racing Club’s 1978 Offshore One-design Conference, which was to select three one-designs to promote in substitution for the then-prevalent IOR system. The three chosen were the Impala, the 101 (designed by Jan Kjaerulff) and Jeremy Rodgers’ OOD 34. Sensing that the 33 foot 101 was too Scandinavian for British tastes, David Thomas decided to scale down to 33 feet. His intention was to design a moderate displacement yacht that would look racy and be competitive under IOR, but be tractable and easy to sail to near optimum speed.

• Initially the class was named the Skua 33, but when a Scottish fleet advised that they were already called Skuas, the name was changed to Sigma 33.

• Built by Marine Projects (Plymouth) Limited in Devon. (Tel:01752-203888)

• Total number built - 364
Starting in December 1978 with hull no. A3001
Ending in December 1991 with hull no. A3364.
(In addition, approximately 44 Sigma 33Cs were built between November 1981 and April 1985, with hull numbers between A4001 and A4212. These have a shorter, masthead rig and a longer, shallower draft keel.)

• Builder’s Dimensions:
L.O.A. 32’ 6” 9.88m
L.W.L. 26’ 3” 8.00m
Beam 10’ 6” 3.20m
Draft 5’ 9” 1.75m
Displacement 9,200lbs 4,182kg

• Construction is straightforward GRP with foam-cored floors and integral bulkheads. Early boats had off-white hull gel coats with either blue or cream decks; later ones had white hulls and decks plus aluminium window frames and go-faster stripes along the coachroof. The interior joinery was also altered.

• Class sails are by Elstrom Sails, HYS, Port Hamble, Hamble, Southampton, Hampshire SO31 4NN. Tel: 023 8045 0430. The class has adopted relatively high-tech Genesis Platinum sails which incorporate kevlar fibres.

• Price when new in 1979 was £16,790 plus VAT. By 1990 this had risen to £37,475 plus VAT.


Jeff Worboys


Saling Area - Solent

Sigma 33 - Workout

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Tony Gorman

South Coast Rep

Sigma 33 - Stan the Boat

Our Committee

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Toby Claridge

South West Coast Rep

Sigma 33 - Excelle


Dan Lewis

Irish Sea Rep

Sigma 33 - Partisan

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Stephen Mulanney

Dublin Bay Rep

Sigma 33 - Insider


Paul Prentice

Northern Ireland Rep

Sigma 33 - Squawk

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Alan Lennox

Scotland Rep

Sigma 33 - Miss Behavin

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James Miller

Scotland Rep

Sigma 33 - Mayrise

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