The Oyster 39 Sailboat
Specs & Key Performance Indicators

The Oyster 39, a centre-cockpit ketch, was designed by Donald Pye and built in the UK by Oyster Marine Ltd.

An Oyster 39

Published Specification for the Oyster 39

Underwater Profile: Fin keel with skeg-hung rudder

Hull Material: GRP (Fibreglass)

Length Overall: 40'8" (12.4m)

Waterline Length: 33'4" (10.2m)

Beam: 12'11" (3.9m)

Draft: 5'8" (1.7m)

Rig Type: Ketch

Displacement: 19,498 lb (8,844 kg)

Designer: Donald Pye

Builder: Oyster Marine Ltd (UK)

Year First Built: 1978

Year Last Built: 1984

Number Built: 43

Published Design Ratios for the Oyster 39

1. Sail Area/Displacement Ratio: Not available

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: 40.1

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

3. Displacement/Length Ratio: 235

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

4. Comfort Ratio: 28.2

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: 1.9

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 Oyster 39

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1. The Sail Area/Displacement Ratio of the Oyster 39 is not published; hence we are unable to comment on this aspect of the yacht's performance.

2. A Ballast/Displacement Ratio of 40.1 means that the Oyster 39 should stand up well to her canvas in a blow, helping her to power through the waves.

3. A Displacement/Length Ratio of 235, tells us the Oyster 39 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 28.2 suggests that crew comfort of a Oyster 39 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 (CSF) of 1.9 tells us that a Oyster 39 would be a safer choice of sailboat for an ocean passage than one with a CSF of more than 2.0.