The Rm 900 is aggressively canvassed for its weight, with a quick, snappy motion best suited to day sailing.
Hull Speed
The theoretical displacement-mode speed limit — determined by waterline length, not engine or sail power.
A displacement hull pushes a bow wave whose speed is limited by the waterline length.
With a waterline of 27.4′, the Rm 900 tops out around 7.0 knots in displacement mode — after that, the bow wave outruns the hull and resistance climbs steeply.
1.34 × √27.4′ LWL = 7.0 kts
Performance Ratios
Racing handicap, sail-carrying power, stability and comfort — and what each one actually tells you about a day on the water.
SA / Displacement
26.0
Performance-oriented — carries a lot of canvas for its weight.
Ballast / Displacement
39.4%
Stiff enough to carry a big genoa comfortably into moderate breeze.
Displacement / Length
158
Moderate — a good balance of speed and load-carrying ability.
Comfort Ratio
15.1
Quick, snappy motion — better for day sails and racing than long passages.
Capsize Screening
2.40
Above the 2.0 offshore threshold — best suited for coastal and protected waters.
Pounds/Inch Immersion
1lbs
Weight needed to sink the hull one inch — loading sensitivity.
Motion & Offshore Suitability
Two ratios that matter most when you're planning passages — how the boat feels in a seaway, and whether the hull geometry is suitable for open ocean.
Comfort Ratio
15.1
Quick, snappy motion — better for day sails and racing than long passages.
Under 20 — Snappy, racing motion
20–30 — Acceptable coastal
30–40 — Good offshore comfort
Over 40 — Very comfortable offshore
Capsize Screening Formula
2.40
Above the 2.0 offshore threshold — best suited for coastal and protected waters.
Under 2.0 — Acceptable for offshore
Over 2.0 — Coastal / protected waters
Estimated Speed by Wind
Rough boat speed estimates at different true wind speeds and points of sail — derived from hull speed, SA/D, and displacement, not measured polars.
| Point of Sail |
6 kts TWS |
10 kts TWS |
15 kts TWS |
20 kts TWS |
| Close-hauled40–50° |
3.3 |
4.2 |
4.7 |
4.9 |
| Close Reach60° |
4.0 |
5.0 |
5.6 |
5.9 |
| Beam Reach90° |
4.9 |
6.2 |
6.9 |
7.5 |
| Broad Reach120–135° |
4.5 |
5.7 |
6.4 |
6.9 |
| Run150–180° |
3.6 |
4.6 |
5.1 |
5.3 |
These are simplified estimates based on hull speed (7.0 kts),
SA/D (26.0), and empirical efficiency curves — not instrument-measured
polars. Real-world speed varies with sea state, bottom condition, sail trim, and current.
Speeds in gold approach hull speed;
bold gold means near or at hull speed.
Wind Range & Comfort Envelope
Estimated wind ranges for comfortable sailing on the Rm 900 — based on sail area, ballast, and displacement characteristics.
Ghost
Sweet Spot
Reef
Heavy
0–5 kts
5–16 kts
16–24 kts
24+ kts
Ghosting
0–5 kts
Light air, motor-sailing likely. Need patience and a light genoa.
Sweet Spot
5–16 kts
Comfortable under full sail. Best speed-to-comfort ratio.
Time to Reef
16–24 kts
Time to shorten sail. Reef the main, swap to a working jib.
Heavy Weather
24+ kts
Storm conditions. Storm jib or bare poles. Seek shelter if coastal.
How It Compares
Side-by-side with the boats most often cross-shopped against the Rm 900.
|
Rm 900 |
Attalia 32 Jeanneau |
Etap 32I |
First 305 Beneteau |
Oceanis 301 Beneteau |
Tempest 31 Westerly |
| Dimensions |
| LOA |
30.6 |
30.5 |
30.7 |
30.5 |
30.5 |
30.6 |
| LWL |
27.4 |
25.9 |
26.3 |
26.8 |
26.3 |
24.5 |
| Beam |
11.6 |
10.8 |
11.2 |
10.5 |
10.8 |
10.8 |
| Displacement |
7 |
7 |
9 |
8 |
8 |
9 |
| Ballast |
2 |
2 |
2 |
2 |
3 |
2 |
| Sail Area |
608 |
410 |
588 |
— |
430 |
400 |
| Performance |
| SA/Disp |
26.0 |
17.2 |
20.7 |
— |
16.1 |
14.8 |
| Bal/Disp |
39.4 |
39.0 |
29.4 |
36.1 |
35.0 |
29.8 |
| Comfort |
15.1 |
17.8 |
21.9 |
— |
— |
22.2 |
| Capsize |
2.40 |
2.22 |
2.10 |
— |
— |
2.08 |
| Hull Speed |
7.0 |
6.8 |
6.9 |
— |
— |
6.6 |