Sigma 33 Ood Information, Review, Specs

Sailing Performance & Handling

The Sigma 33 OOD is renowned for its "stiff" and powerful feel, a direct result of its high ballast ratio, which exceeds 45%. With a displacement of approximately 4,173 kg (9,200 lbs) and nearly 1,900 kg of that located in the deep fin keel, the boat stands up well to its canvas and handles heavy weather with a composure that inspired confidence during the 1979 Fastnet race, which two Sigmas successfully survived. The rig is a deck-stepped fractional sloop, a choice that allows for significant control over mast bend and sail shape—vital for the close-quarters racing the class is known for.

Under sail, the boat typically tracks well with a responsive tiller that provides excellent feedback. While critics in the early 1980s jokingly referred to it as the "six knots up, six knots down" boat, this was more a testament to its consistency across conditions than a lack of speed. In reality, the 33 OOD is a surprisingly quick passage maker. Owners report that the boat feels balanced and predictable upwind, though like many designs of its era with narrower stern sections, it requires an attentive hand on the helm when carrying a large spinnaker in a following sea to prevent rhythmic rolling.

Interior Comfort & Variations

Unlike many dedicated racing machines of the late 1970s, the Sigma 33 OOD was designed with a "proper" cruising interior. The layout is a traditional British arrangement: a V-berth in the forecabin, a heads compartment to port with a hanging locker opposite, and a main saloon with two settee berths (plus pilot berths on some models). Headroom is generous for a boat of this vintage, standing at approximately 6ft 1in (1.85m). The galley is located to starboard, featuring a twin burner hob and oven, while a dedicated chart table sits to port, followed by a large quarter berth.

The most significant variation of this hull is the Sigma 33C (Cruising). The 33C was "de-tuned" to make it more manageable for short-handed crews. It features a shorter masthead rig, which lacks the high-tension running backstays often found on racing-tuned OOD models, and a shallower but heavier keel to maintain stability. While the 33C is less common on the second-hand market than the OOD, it is highly sought after by dedicated cruisers who prioritize ease of handling over class racing potential.

Popular Mentions & Media

The Sigma 33 OOD remains a staple of the UK racing scene, frequently fielding one of the largest one-design fleets at major regattas like Cowes Week and the West Highland Yachting Week. Its reputation as a "bulletproof" offshore vessel was further cemented by sailors like Will Sayer, who famously refitted an older Sigma 33 and competed in the OSTAR (Original Single-handed Transatlantic Race). The class's longevity is sustained by a vibrant and organized community that continues to hold annual National Championships across the UK and Ireland.

Known Issues & Buyer’s Checklist

Prospective buyers should approach a Sigma 33 with a focus on its structural history, as many have been raced hard for decades.

• Keel-to-Hull Joint: The cast iron keel is flanged and fits into a recess in the hull. Grounding at speed can cause "compression" at the trailing edge of the keel, leading to hull distortion or beam fracture in the bilge.
• Chainplates and Rigging: Due to the high rig tensions required for competitive racing, leaking chainplates are a common "gotcha." These leaks can lead to moisture in the bulkheads if not addressed. Additionally, the availability of the original mast extrusion has become an issue, leading the Sigma 33 Class Association to source its own custom extrusions for replacements.
• Steel Fuel Tanks: The original mild steel fuel tanks are prone to internal corrosion. Many owners have replaced these with stainless steel or plastic units to prevent engine failure.
• Engine Maintenance: Many original boats were fitted with the Volvo Penta MD2002 or 2003. These are aging, and buyers should check for exhaust elbow blockages and cooling system scale, though many examples have since been re-engined with modern Yanmar or Nanni units.
• Rudder Bearings: Play in the spade rudder bearings is common. Removal of the rudder for bearing replacement usually requires digging a pit or lifting the boat significantly high, which adds to maintenance costs.

Community & Resources

The boat is supported by the Sigma 33 Class Association, one of the most active owner groups in Europe. They maintain the official class rules, organize national championships, and provide a vital technical wiki for owners looking to source spare parts or advice on rig tuning.

The Verdict

The Sigma 33 OOD is perhaps the definitive example of a boat that does everything well. It is fast enough to win trophies, tough enough to cross oceans, and comfortable enough for a family of four to spend a fortnight aboard.

Pros:

• Exceptional value for money in the 33-foot market.
• Strong one-design racing fleet ensures the boat retains its resale value.
• High ballast ratio provides a "big boat" feel and excellent stability.
• The interior is practical and genuinely usable at sea.

Cons:

• Many examples on the market are "tired" from years of racing.
• The iron keel requires constant maintenance to prevent rust blooms.
• The fractional rig and running backstays (on OOD models) can be complex for novice cruisers.