The Twister 28 Sailboat
Specs & Key Performance Indicators

The Twister 28, a long-keeled sloop, was designed by Kim Holman and built in the UK by Tyler Boat Co Ltd and Uphams Ltd.

A Twister 28 moored alongside the Tamar River Sailing Club in Plymouth UK, with Isambard Kingdom Brunel's famous railway bridge in the background.

Published Specification for the Twister 28

Underwater Configuration: Long keel with transom-hung rudder

Hull Material: GRP (Fiberglass)

Length Overall: 28' 3" / 8.6m

Waterline Length: 21' 6" / 6.6m

Beam: 8' 1" / 2.5m

Draft: 5' 0" / 1.5m

Rig Type: Masthead sloop

Displacement: 9,968lb / 4,521kg

Designer: Kim Holman

Builder: Uphams (UK) and Tyler (UK)

Year First Built: 1964

Year Last Built: 1983

Number Built: 200

Owners Association: Twister Class Association

A wooden Twister 28

Published Design Ratios for the Twister 28

1. Sail Area/Displacement Ratio: 12.1

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: 46.4

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

3. Displacement/Length Ratio: 448

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

4. Comfort Ratio: 40.5

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: 1.5

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 Twister 28

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1. A Sail Area/Displacement Ratio of just 12.1 suggests that she'll need a stiff breeze to get her going. In light conditions, unless you've got plenty of time on your hands, motor-sailing may be the way to go.

2. A Ballast/Displacement Ratio of 46.4 means that she'll stand up well to her canvas in a blow, helping her to power through the waves.

3. A Displacement/Length Ratio of 448, tells us she's firmly in the ultra-heavy displacement category. Load her up as much as you like and her performance will be hardly affected, not that it was ever startling. 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 40.5 suggests that crew comfort in a seaway is similar to what you would associate with the motion of a heavy bluewater cruising boat. Pitching and rolling will be well damped - your cup of coffee on the salon table stands a good chance of staying there in reasonable conditions.

5. Her Capsize Screening Formula (CSF) of 1.5 tells us that she would be a safer choice of sailboat an ocean passage than one with a CSF of more than 2.0.