BoatsSeamaster Sailer 23

Seamaster Sailer 23

Masthead Sloop · Fin w/transom Hung Rudder · 1969–1975

A Laurent Giles-designed masthead sloop built for versatility, offering three keel options and a choice of engine types

Designed by Laurent Giles & Jack Laurent Giles.

LOA
Beam
Draft (max)
Displacement
Ballast
Hull type
Fin w/transom Hung Rudder

Is it for you?

Character

Where this design lands on the numbers a shopper trusts — read straight from her own ratios.

Shoal draughtDraws 1.07 m, board up where she has one — creeks, sandbars and thin anchorages most keels have to stay out of.
LivelySea-kindly

Her heavy displacement on a beamy beam gives 22 — a moderate, middle-of-the-road motion.

Comfort ratio 22
CoastalBluewater

1.94 — just under the 2.0 offshore line; her beam is modest for her weight.

Capsize screening 1.94
LightHeavy

287 — heavy for her waterline, built to carry stores and ride steadily.

Displacement / length 287
EasygoingPowered-up

12.7 — modest power for her weight; easygoing rather than lively, and happier with a breeze.

Sail area / displacement 12.7
TenderStiff

40% of her weight is ballast — moderately stiff, a middle-of-the-road stability.

Ballast 40%

A capable cruiser that sits just inside the offshore line — coastal work with real passages in her.

The record

Full specifications

The complete reference set — tap any figure to switch between metric and imperial.

Dimensions
Weights
Ballast / displacement
40.3%
Rig & sail area
Rig
Masthead Sloop
Ratios
SA / displacement
12.7
Displacement / length
287.4
Comfort ratio
22.2
Capsize screening
1.94
Hull speed
6.0 kn
Pounds / inch immersion
582
Hull
Hull type
Fin w/transom hung rudder
Construction
Fiberglass
Production
Years built
1969–1975
Designer
Laurent Giles, Jack Laurent Giles
Builder
Seamaster Ltd

Boats like this, on the water

Nobody has filmed this one — but these are close.

Comparable boats the fleet has on camera: same type, within a quarter of her length. Open the boat, or watch the video — a timestamp means she only appears in passing.

Jeanneau Sun Odyssey 267.47 mSame hull family0.5 m longerA Philippe Briand-designed fractional sloop built for coastal cruising with a stiff, stable hull form
Galion 226.71 mSame hull family0.3 m shorterDesigned by Ian Hannay, this fractional sloop proved her mettle by winning both the Round the Island and JOG races in 1968
Hurley 226.71 mSame hull family0.3 m shorterA long-running Ian Anderson design with a heavy ballast ratio, produced by multiple builders over three decades
Comet 7707.70 mSame hull family0.7 m longerA Jean-Marie Finot-designed IOR quarter-tonner with a high sail-area-to-displacement ratio for spirited club racing
Cal 257.62 mSame hull family0.6 m longerA flush-deck masthead sloop featuring a pop-top companionway that became one of the most popular models in the fleet
Martinique 257.70 mSame hull family0.7 m longerA Brazilian-built masthead sloop with a 44% ballast ratio, offering a stiff and stable platform for coastal cruising

The family

Boats like this

Nearby designs by size, type, and era — worth a look alongside her.

Keep looking

Nothing filmed of this one yet

Two ways to keep looking — both search what the fleet has actually recorded.

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