Published Design Ratios for the Bowman 57
1. Sail Area/Displacement Ratio: 17.1
- 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: 38.1
- Under 40: less stiff, less powerful
- Over 40: stiffer, more powerful
3. Displacement/Length Ratio: 220
- Under 100: Ultralight
- 100 to 200: Light
- 200 to 275: Moderate
- 275 to 350: Heavy
- Over 350: Ultraheavy
4. Comfort Ratio: 37.6
- 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: 1.7
- 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 Bowman 57
1. A Sail Area/Displacement Ratio of 17.1 suggests that the Bowman 57 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 38.1 means that a sailboat like the Bowman 57 (which doesn't have its ballast concentrated in a bulb at the foot of a deep keel), is likely to benefit from being reefed early to keep her sailing upright in a moderate breeze.
3. A Displacement/Length Ratio of 220, tells us the Bowman 57 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 37.6 suggests that crew comfort of a Bowman 57 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 Bowman 57 would be a safer choice of sailboat for an ocean passage than one with a CSF of more than 2.0.