The Hunter 31 Sailboat
Specs & Key Performance Indicators

Published Specification for the Hunter 31

Underwater Profile: Fin keel & spade rudder

Hull Material: GRP (Fibreglass)

Length Overall: 31'4" (9.6m)

Waterline Length: 26'3" (8.0m)

Beam: 10'11" (3.4m)

Draft: 5'3" (1.6m)

Rig Type: B&R

Displacement: 9,700lb (4,400kg)

Ballast: 4,000lb (1,814kg)

Designer: Cortland Steck

Builder: Hunter Marine (USA)

Year First Built: 1983

Year Last Built: 1987

Published Design Ratios for the Hunter 31

1. Sail Area/Displacement Ratio: 16.2

• 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: 41.2

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

3. Displacement/Length Ratio: 239

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

4. Comfort Ratio: 22.4

• 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: 2.1

• 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 Hunter 31

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1. A Sail Area/Displacement Ratio of 16.2 suggests that the Hunter 31 will, in the right conditions, approach her maximum hull speed readily and satisfy the sailing performance expectations of most cruising sailors.

2. A Ballast/Displacement Ratio of 41.2 means that the Hunter 31 will stand up well to her canvas in a blow, helping her to power through the waves.

3. A Displacement/Length Ratio of 239, tells us the Hunter 31 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 22.4 suggests that crew comfort of a Hunter 31 in a seaway is similar to what you would associate with the motion of a coastal cruiser with moderate stability, which is not the best of news for anyone prone to seasickness. 

5. The Capsize Screening Formula of 2.1 tells us that a Hunter 31 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.