The Grand Soleil 343 Sailboat
Specs & Key Performance Indicators

The Grand Soleil 343, a light-displacement sloop, was designed by Alain Jezequel and built in Italy by Grand Soleil.

A Grand Soleil 343 sailboat moored on the River Tamar in southwest EnglandA Grand Soleil 343 Sailboat

Published Specification for the Grand Soleil 343

Underwater Profile: Fin keel & spade rudder

Hull Material: GRP (Fibreglass)

Length Overall: 34'2" (10.4m)

Waterline Length: 28'9" (8.8m)

Beam: 11'3" (3.4m)

Draft: 5'11" (1.8m)

Rig Type: Masthead sloop

Displacement: 10,251lb (4,650kg)

Ballast: 3,858lb (1,750kg)

Designer: Alain Jezequel

Builder: Grand Soleil (Italy)

Year First Built: 1985


Published Design Ratios for the Grand Soleil 343

1. Sail Area/Displacement Ratio: 22.8

  • 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: 37.6

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

3. Displacement/Length Ratio: 193

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

4. Comfort Ratio: 20.9

  • 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 Grand Soleil 343

1. A Sail Area/Displacement Ratio of 22.8 suggests that, in the right hands, the Grand Soleil 343 will have enough performance to leave most other sailboats of similar waterline length well astern. 

2. A Ballast/Displacement Ratio of 37.6 means that a sailboat like the Grand Soleil 343 (which doesn't have a stiffness-enhancing bulb keel), is likely to benefit from being reefed early to keep her sailing upright in a moderate breeze.

3. A Displacement/Length Ratio of 193, tells us the Grand Soleil 343 is clearly a light 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 20.9 suggests that crew comfort of a Grand Soleil 343 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 Grand Soleil 343 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.

Other sailboats in the Grand Soleil range include:


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