The Sundeer 56 Sailboat
Specs & Key Performance Indicators

The Sundeer 56, an ultra-light fractional sloop, was designed by Steve Dashew and built in the USA by TPI Composites as a shortened version of the Sundeer 60.

'Scraatch', a Sundeer 56 long-distance cruiser at anchor off Ste Anne, Martinique.

Published Specification for the Sundeer 56

Underwater Profile: Fin keel & spade rudder
Hull Material: GRP (Fibreglass)
Length Overall: 56'11" (17.4m)
Waterline Length: 56'0" (17.1m)
Beam: 13'9" (4.2m)
Draft: 6'0" (1.8m)
Rig Type: Fractional Sloop
Displacement: 34,600lb (15,695kg)
Designer: Steve Dashew
Builder: TPI Composites (USA)
Year First Built: 1994
Year Last Built: 1997
Number Built: 17

Published Design Ratios for the Sundeer 56

1. Sail Area/Displacement Ratio: 15.7

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: 28.9

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

3. Displacement/Length Ratio: 88.0

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

4. Comfort Ratio: 29.1

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

Summary Analysis of the Design Ratios for the Sundeer 56

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1. A Sail Area/Displacement Ratio of almost 16.0 suggests that the Sundeer 56 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 28.9 means that a sailboat like the Sundeer 56 (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 just 88 places her firmly in the ultralight category.

4. Ted Brewer's Comfort Ratio of 29.1 suggests that crew comfort of a Sundeer 56 in a seaway is similar to what you would associate with the motion of a coastal cruiser with moderate stability, which is not encouraging news for anyone prone to seasickness.

5. The Capsize Screening Formula (CSF) of 1.7 tells us that a Sundeer 56 would be a safer choice of sailboat for an ocean passage than one with a CSF of more than 2.0.