The Swan 43 Sailboat
Specs & Key Performance Indicators

The Swan 43, a masthead sloop, was designed by Sparkman & Stephens and built in Finland by Nautor Swan.

'Thistle', a classic S&S designed Swan 43 sailboat from the 1970s.The S&S designed Swan 43

Published Specification for the Swan 43

Underwater Profile: Fin keel with skeg-hung rudder

Hull Material: GRP

Length Overall: 42'9" (13.0m)

Waterline Length: 31'0" (9.5m)

Beam: 11'8" (3.6m)

Draft: 7'2" (2.2m)

Rig Type: Sloop

Displacement: 19,850lb (9,000kg)

Designer: Sparkman & Stephens

Builder: Nautor Swan

Year First Built: 1967

Year Last Built: 1982

Number Built: 67

Owners Association: S&S Swan Association

Published Design Ratios for the Swan 43

1. Sail Area/Displacement Ratio: 18.1

  • 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: 52.4

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

3. Displacement/Length Ratio: 297

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

4. Comfort Ratio: 33.7

  • 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 Swan 43

1. A Sail Area/Displacement Ratio of 18.1 suggests that the Swan 43 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 52.4 means that the Swan 43 will stand up well to her canvas in a blow, helping her to power through the waves.

3. A Displacement/Length Ratio of 297, tells us the Swan 43 is clearly a heavy displacement cruising boat. You can load her down with all your cruising gear and equipment and it will hardly affect her waterline. Not an ideal choice for coastal sailing, but she'll come into her own on an offshore passage in testing conditions.

4. Ted Brewer's Comfort Ratio of 33.7 suggests that crew comfort of a Swan 43 in a seaway is similar to what you would associate with the motion of a moderate bluewater cruising boat - a predictable and acceptable motion for most seasoned sailors.

5. The Capsize Screening Formula (CSF) of 1.7 tells us that a Swan 43 would be a safer choice of sailboat for an ocean passage than one with a CSF of more than 2.0. 

Other sailboats in the Nautor Swan range include:


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