The Pearson 365 Ketch
Specs & Key Performance Indicators

The Pearson 365 Ketch, a heavy displacement aft-cockpit cruiser, was designed by William Shaw and built in the USA by Pearson Yachts.

A Pearson 365 Ketch

Published Specification for the Pearson 365 Ketch

Underwater Profile: Fin keel with skeg-hung rudder

Hull Material: GRP (Fibreglass)

Length Overall: 36'5" (11.1m)

Waterline Length: 30'0" (9.1m)

Beam: 11'5" (3.5m)

Draft: 4'6" (1.4m)

Rig Type: Ketch*

Displacement: 17,700lb (8,029kg)

Designer: William Shaw

Builder: Pearson Yachts (USA)

Year First Built: 1976

Year Last Built: 1982

* Also available as a sloop or cutter

Published Design Ratios for the Pearson 365 Ketch

1. Sail Area/Displacement Ratio: 14.5

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: 41.2

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

3. Displacement/Length Ratio: 293

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

4. Comfort Ratio: 33.4

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: 1.8

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 Pearson 365 Ketch

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1. A Sail Area/Displacement Ratio of 14.5 suggests that the Pearson 365 Ketch will 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 41.2 means that the Pearson 365 Ketch will stand up well to her canvas in a blow, helping her to power through the waves.

3. A Displacement/Length Ratio of 293, tells us the Pearson 365 Ketch 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 33.4 suggests that crew comfort of a Pearson 365 Ketch 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 1.8 indicates that a Pearson 365 Ketch would be a safer choice of sailboat for an ocean passage than one with a CSF of more than 2.0.