The Moody 33 Sailboat
Specs & Key Performance Indicators

The Moody 33 is a classic cruising sailboat designed by Angus Primrose and built by Marine Projects Ltd in the UK .

The boat features a centre-cockpit layout with a separate aft cabin, a fin keel with a skeg-hung rudder, and a masthead sloop rig and is known for its solid construction, spacious interior, and seaworthy performance.

The centre-cockpit Moody 33 has a separate aft cabin

The Moody 33 was first introduced in 1973 and was the first Moody design specifically aimed at mass production rather than semi-custom designs, and rapidly became very popular.

The Moody 33 went through several minor revisions during its production run. The Mk I models were built until 1976, and Mk II models were produced from 1976 to 1981. The Mk II had slight variations in internal layout, including changes to the galley, chart table, and saloon. Externally, the only obvious difference was that Mk Is had a central hatch to the aft cabin, while Mk IIs had an offset hatch to port .

From 1979 to 1981, an aft-cockpit version called the Moody 33S was available.

Published Specification for the Moody 33

Underwater Profile: Fin & Skeg
Hull Material: GRP (Fibreglass)
Length Overall: 33'0" (10.1m)
Waterline Length: 28'6" (8.7m)
Beam: 11'6" (3.5m)
Draft: 4'5" (1.35m)
Rig Type: Masthead sloop
Displacement: 10,523lb (4,773kg)
Designer: Angus Primrose
Builder: Marine Projects (UK)
Owners Association: Moody Owners Association

Summary Analysis of the Design Ratios for the Moody 33

The Sail Area/Displacement Ratio of 15.1 suggests that it is somewhat underpowered, as it falls just below the threshold for reasonably good performance, which starts at 16. This implies that the boat might not be as swift as others with higher ratios, especially in lighter winds.

With a Ballast/Displacement Ratio of 36.2, the Moody 33 is reasonably adept at maintaining stability in winds but does not reach the level often associated with stiffer, more powerful boats typically marked by ratios of 40 or more. The effectiveness of this ratio is limited by not considering the distribution of ballast; a deeper keel could potentially enhance performance and stability further.

The Displacement/Length Ratio of 303 places the Moody 33 firmly within the heavy displacement category. This indicates a vessel more capable of handling rougher waters with a slightly reduced speed potential, requiring more sail area to reach its hull speed compared to lighter vessels.

The Comfort Ratio of 21.0 suggests that the Moody 33 would offer a motion comfort level typical of a coastal cruiser, capable of managing moderate sea conditions while providing a relatively stable and comfortable ride. This metric, however, leans towards favoring traditional heavy displacement designs, and as a result might not accurately reflect the comfort of modern, beamier cruisers.

Lastly, a Capsize Screening Formula score of 2.1 indicates that while the Moody 33 is capable of coastal cruising, it slightly exceeds the ideal maximum for bluewater sailing, measured at 2.0 or lower. This suggests adequate stability for ocean passages but warrants caution, especially in severe conditions.

Overall, these ratios offer a guideline and are inherently theoretical, including the limitations such as the static nature of ballast placement in computing the Ballast/Displacement Ratio, and the potential discrepancies in the Comfort Ratio, which might not always correspond to real-world comfort perceptions in modern yacht designs.

This article was written with the assistance of Gemini, a large language model developed by Google. Gemini was used to gather information, summarize research findings, and provide suggestions for the content and structure of the article.