Monsun 31
Masthead Sloop · Long Keel · 1974–1982
A long-keeled masthead sloop with a 45% ballast ratio, built for offshore stability and also marketed as the Rasmus 31
Designed by Olle Enderlein, built by Hallberg-Rassy.
- LOA
- Beam
- Draft (max)
- Displacement
- Ballast
- Hull type
- Long Keel
Is it for you?
Character
Where this design lands on the numbers a shopper trusts — read straight from her own ratios.
Her heavy displacement on a moderate beam gives 27 — a moderate, middle-of-the-road motion.
1.80 — just under the 2.0 offshore line; her beam is modest for her weight.
275 — heavy for her waterline, built to carry stores and ride steadily.
15.1 — moderate power for her weight; steady, all-round performance.
45% of her weight is ballast — stiff, standing up well to her sails.
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.
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.
The family
Related models
The designs closest to hers — usually the rest of the builder's range, sometimes the same hull sold under another name.
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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