Sail area / displacement
How much sail the boat carries for its weight — its power in light air.
- 24.4· Racing
How it is worked out
sail area (ft²) ÷ (displacement as ft³ of seawater)^⅔
published upwind sail area

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Photographe-La-Rochelle-Sylvie-Curty-BD-2259 — Sylvie Curty (via RM Yachts)
* A standard reference image, not the actual boat — shown to help visualise this model's published dimensions.
From the published figures: hull length 13.3 m · upwind 110 m²
Tags are derived from certified class, length, sail area, accommodation and tankage using the criteria described on the Sources page; an editor may add or remove one.
Classic yacht-design ratios worked out from the builder's published figures, each shown against the bands designers read it by.
How much sail the boat carries for its weight — its power in light air.
sail area (ft²) ÷ (displacement as ft³ of seawater)^⅔
published upwind sail area
How heavy the boat is for its waterline length. Lower is lighter and quicker; higher is steadier and roomier.
displacement (long tons) ÷ (0.01 × waterline length in ft)³
The share of the weight carried in the keel — a rough guide to stiffness, though how deep that weight sits matters as much.
ballast ÷ displacement × 100
Ted Brewer's measure of how gently a boat moves in a seaway. Higher means a slower, easier motion.
displacement (lb) ÷ (0.65 × (0.7 × LWL + 0.3 × LOA) × beam^1.333), lengths in ft
A guide from the inquiry after the 1979 Fastnet race: below 2 was taken as suited to ocean passages. It ignores hull shape and where the ballast sits.
beam (ft) ÷ (displacement as ft³ of seawater)^⅓
Roughly the speed a displacement hull reaches before it has to climb its own bow wave.
1.34 × √(waterline length in ft), in knots
Most builders publish a light displacement. The ratios were defined on a loaded boat, so every boat here reads a little lighter than a surveyor's figure would — all alike, which keeps them comparable.
What the builder publishes about how fast, how strong and how much the boat carries.
Fuel and water on one scale: a tank twice the height holds twice as much.
Figures read fromrm-yachts.com/en/rm-1380-45-foot-sailboat/· Technical specificationsread 9/13/2026
Semi-custom
French builder of plywood-epoxy performance cruising yachts from 30 to 45 feet — the RM 890+, 980, 1080, 1180 and 1380, all drawn by Marc Lombard — building at La Rochelle since 1989, with more than 600 boats sailing.
RM has been building since 1989, and the yard's own archive of every model it has made since then counts more than 600 RM sailing today, around the world.
Visit brand pageEvery model RM Yachts publishes, by length — where this one sits in the range.
Boats this boat's designers also drew, for other builders too. Credits are grouped only where the names clearly agree, however each builder spelled them; an unclear one is left out.