The Oyster 575 Sailboat
Specs & Key Performance Indicators

Published Specification for the Oyster 575

Underwater Profile: Fin keel and spade rudder

Hull Material: GRP (Fibreglass)

Length Overall: 58'8" (17.9m)

Waterline Length: 51'6" (15.7m)

Beam: 16'5" (5.0m)

Draft: 8'10" (2.7m)*

Rig Type: Cutter

Displacement: 58,422lb (26,500kg)

Designer: Rob Humphreys

Builder: Oyster Marine (UK)

Year First Built: 2010

* A shoal draft and a centreboard version are also available.

Published Design Ratios for the Oyster 575

1. Sail Area/Displacement Ratio: 22.4

• 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: 30.6

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

3. Displacement/Length Ratio: 191

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

4. Comfort Ratio: 40.5

• 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: 1.7

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

Read more about these Key Performance Indicators...

Summary Analysis of the Design Ratios for the Oyster 575

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1. A Sail Area/Displacement Ratio of 22.4 suggests that, in the right hands, the Oyster 575 will have enough performance to leave most other sailboats of similar waterline length well astern. 

2. A Ballast/Displacement Ratio of 30.6 would usually mean that the Oyster 575 would have a tendency to heel uncomfortably in a gust, and need to be reefed early to keep her sailing upright in a moderate breeze.

However, as she has much of her ballast concentrated in a bulb at the foot of her keel, she's likely to be considerably stiffer than her published Ballast/Displacement Ratio might suggest.

3. A Displacement/Length Ratio of 191, tells us the Oyster 575 is a light-to-moderate displacement sailboat. If she's loaded with too much heavy cruising gear her performance will suffer to a degree.

4. Ted Brewer's Comfort Ratio of 40.5 suggests that crew comfort of an Oyster 575 in a seaway is similar to what you would associate with the motion of a heavy bluewater cruising boat. Pitching and rolling will be well damped - your cup of coffee on the salon table stands a reasonable chance of staying there in most conditions.

5. The Capsize Screening Formula (CSF) of 1.7 tells us that an Oyster 575 would be a safer choice of sailboat for an ocean passage than one with a CSF of more than 2.0.