The Westerly Ocean 33 Sailboat
Specs & Key Performance Indicators

The Westerly Ocean 33, an aft-cockpit fractional sloop, was designed by Ed Dubois and built in the UK by Westerly Marine Ltd.

A Westerly Ocean 33 moored on the River Tamar near Plymouth UK

The Westerly Ocean 33 was the final model to be built by Westerly Marine in the UK

Published Specification for the Westerly Ocean 33

Underwater Profile: Fin keel & spade rudder*

Hull Material: GRP (Fibreglass)

Length Overall: 33'4" (10.2m)

Waterline Length: 28'3" (8.6m)

Beam: 11'2" (3.4m)

Draft: 5'6" (1.7m)*

Rig Type: Fractional sloop

Displacement: 11,023lb (5,000kg)

Designer: Ed Dubois

Builder: Westerly Marine Ltd (UK)

Year First Built: 1997

Year Last Built: 2000

Number Built: 33

* A bilge keel version was also produced, with a draft of 4'0" (1.2)

Published Design Ratios for the Westerly Ocean 33

1. Sail Area/Displacement Ratio: Not published

Less than 16 would be considered under-powered;
16 to 20 would indicate reasonably good performance;
Over 20 suggests relatively high performance.

2. Ballast/Displacement Ratio: 40.4

Under 40: less stiff, less powerful
Over 40: stiffer, more powerful

3. Displacement/Length Ratio: 218

Under 100: Ultralight
100 to 200: Light
200 to 275: Moderate
275 to 350: Heavy
Over 350: Ultraheavy

4. Comfort Ratio: 23.0

Under 20 indicates a lightweight racing boat
20 to 30 indicates a coastal cruiser
30 to 40 indicates a moderate offshore cruising boat
40 to 50 indicates a heavy offshore boat
Over 50 indicates an extremely heavy offshore boat

5. Capsize Screening Formula: 2.0

Under 2.0 (the lower the better): Better suited for ocean passages
Over 2.0: Less suited for ocean passages

Summary Analysis of the Design Ratios for the Westerly Ocean 33

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1. In the absence of any published Sail Area/Displacement Ratio data, we are unable to make any assessment of the Westerly Ocean 33's power under sail.

2. A Ballast/Displacement Ratio of 40.4 means that the Westerly Ocean 33 will stand up well to her canvas in a blow, helping her to power through the waves.

3. A Displacement/Length Ratio of 218, tells us the Westerly Ocean 33 is a moderate displacement cruiser, which means she'll carry all your cruising gear without it having a dramatic effect on her performance. Most of today's sailboats intended for offshore cruising fall into this displacement category.

4. Ted Brewer's Comfort Ratio of 23.0 suggests that crew comfort of a Westerly Ocean 33 in a seaway is similar to what you would associate with the motion of a coastal cruiser with moderate stability, which is not encouraging news for anyone prone to seasickness.

5. The Capsize Screening Formula of 2.0 tells us that a Westerly Ocean 33 would not be as good a choice of sailboat for ocean passage-making, owing to the increased risk of capsize in strong winds and heavy seas when compared to a sailboat with a CSF of less than 2.0.