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, and remained in production until late 1983.

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

Published Design Ratios for the Moody 33

1. Sail Area/Displacement Ratio: 15.1

2. Ballast/Displacement Ratio: 36.2

3. Displacement/Length Ratio: 303

4. Comfort Ratio: 21.0

5. Capsize Screening Formula: 2.1

Summary Analysis of the Design Ratios for the Moody 33

Based on the above design ratios, the Moody 33 would have the following theoretical sailing characteristics:

Sail Area/Displacement Ratio (15.1): This ratio is slightly below the threshold for good performance (16), suggesting that the Moody 33 might be somewhat underpowered. It may not accelerate as quickly or reach as high a top speed as boats with a higher ratio.

Ballast/Displacement Ratio (36.2): This ratio is close to 40, indicating that the Moody 33 has a reasonable amount of stiffness and power to stand up to the wind. However, as you noted, this ratio doesn't account for the location of the ballast. If the Moody 33 has a shallow draft keel, it might be less stiff than a similar boat with its ballast in a bulb at the foot of its keel.

Displacement/Length Ratio (303): This ratio falls into the Heavy Displacement category, suggesting that the Moody 33 is a relatively heavy boat. It will require more sail area to reach its design hull speed compared to lighter boats.

Comfort Ratio (21.0): This ratio indicates that the Moody 33 is likely to have a motion similar to a coastal cruiser. It should provide a reasonable level of comfort in most conditions, but may not be as comfortable in heavy seas or high winds as boats with a higher comfort ratio.

Capsize Screening Formula (2.1): This value is slightly above the threshold for blue water capability (2.0), suggesting that the Moody 33 might be more suited to coastal cruising than ocean passages.

As mentioned previously, these ratios are theoretical and have their limitations. For example, the Ballast/Displacement Ratio doesn't account for the location of the ballast, which can significantly affect a boat's stiffness and stability.

Similarly, Ted Brewer's Comfort Ratio favors heavy displacement, narrow-beamed vessels with long overhangs.

Today's light-displacement, beamy cruisers with plumb bows may not score well on this ratio, even though they may be quite capable and comfortable in blue water conditions.

It's always important to consider these ratios in context and in conjunction with other factors when assessing a boat's likely performance and comfort.

Your Moody 33 questions answered...

Were alternative versions of the Moody 33 sailboat produced?

Yes, there were alternative versions of the Moody 33 sailboat. From 1979 to 1981, an aft-cockpit version, the 33S, was also offered.

Were there later Mks of the Moody 33 sailboat?

Yes, there were later Mks of the Moody 33 sailboat. The Mk I models were built until 1976, and Mk II from 1976-1981. They have slight variations in internal layout, to the galley, chart table, and saloon. Externally the only obvious difference is that Mk Is have a central hatch to the aft cabin, whilst in Mk IIs this is offset to port.