The Jongert 21S Sailboat
Specs & Key Performance Indicators
The Jongert 21S, a steel hulled ketch, was designed by Doug Peterson and Peter Sijm and built in the Netherlands by Jongert.
A Jongert 21S
Published Specification for the Jongert 21S
- Underwater Profile: Fin keel & Skeg-hung rudder
- Hull Material: Steel
- Length Overall: 72'0" (22.0m)
- Waterline Length: 51'0" (15.5m)
- Beam: 18'7" (5.7m)
- Draft: 10'2" (3.1m)
- Rig Type: Masthead Ketch
- Displacement: 110,400lb (49,895kg)
- Designer: Doug Peterson & Peter Sijm
- Builder: Jongert (Netherlands)
- Year First Built: 1981
Published Design Ratios for the Jongert 21S
1. Sail Area/Displacement Ratio: Not published
- 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: 18.2
- Under 40: less stiff, less powerful
- Over 40: stiffer, more powerful
3. Displacement/Length Ratio: 370
- Under 100: Ultralight
- 100 to 200: Light
- 200 to 275: Moderate
- 275 to 350: Heavy
- Over 350: Ultraheavy
4. Comfort Ratio: 60.6
- 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: 1.6
- 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 Jongert 21S
1. The Sail Area/Displacement Ratio of the Jongert 21S is not possible, hence we are unable to comment on this boat's predicted performance.
2. A Ballast/Displacement Ratio of 18.2 means that the
is likely to benefit from being reefed early to keep her sailing upright in a moderate breeze.
3. A Displacement/Length Ratio of 370, tells us the xxxxx is firmly in the ultra-heavy displacement category. Load her up as much as you like and her performance will be hardly affected. Few if any sailboats are built to this displacement category these days - but they remain popular with some long-distance sailors.
4. Ted Brewer's Comfort Ratio of 60.6 suggests that crew comfort of a xxxx in a seaway is similar to what you would associate with the motion of an extremely heavy bluewater boat - and that's as comfortable as life ever gets on a sailing boat!
5. The Capsize Screening Formula (CSF) of 1.6 tells us that a xxxx would be a safer choice of sailboat for an ocean passage than one with a CSF of more than 2.0.
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