The Oceanis 39 Beneteau is moderately powered for comfortable coastal cruising, with acceptable motion comfort for coastal passages.
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 33.3′, the Oceanis 39 Beneteau tops out around 7.7 knots in displacement mode — after that, the bow wave outruns the hull and resistance climbs steeply.
1.34 × √33.3′ LWL = 7.7 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
17.1
Moderate sail power — a capable coastal cruiser, not overpowered.
Ballast / Displacement
36.2%
Typical cruising ballast — balanced stability and motion underway.
Displacement / Length
173
Moderate — a good balance of speed and load-carrying ability.
Comfort Ratio
21.2
Acceptable coastal comfort — fine for weekends, notice the chop offshore.
Capsize Screening
2.11
Above the 2.0 offshore threshold — best suited for coastal and protected waters.
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
21.2
Acceptable coastal comfort — fine for weekends, notice the chop offshore.
Under 20 — Snappy, racing motion
20–30 — Acceptable coastal
30–40 — Good offshore comfort
Over 40 — Very comfortable offshore
Capsize Screening Formula
2.11
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° |
3.1 |
3.9 |
4.4 |
4.5 |
| Close Reach60° |
3.7 |
4.7 |
5.3 |
5.5 |
| Beam Reach90° |
4.6 |
5.8 |
6.5 |
7.0 |
| Broad Reach120–135° |
4.2 |
5.3 |
6.0 |
6.5 |
| Run150–180° |
3.4 |
4.3 |
4.8 |
5.0 |
These are simplified estimates based on hull speed (7.7 kts),
SA/D (17.1), 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 Oceanis 39 Beneteau — based on sail area, ballast, and displacement characteristics.
Ghost
Sweet Spot
Reef
Heavy
0–7 kts
7–20 kts
20–28 kts
28+ kts
Ghosting
0–7 kts
Light air, motor-sailing likely. Need patience and a light genoa.
Sweet Spot
7–20 kts
Comfortable under full sail. Best speed-to-comfort ratio.
Time to Reef
20–28 kts
Time to shorten sail. Reef the main, swap to a working jib.
Heavy Weather
28+ 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 Oceanis 39 Beneteau.
|
Oceanis 39 Beneteau |
Oceanis 381 Beneteau |
Oceanis 393 Beneteau |
Oceanis 400 Beneteau |
Oceanis 440 Beneteau |
| Dimensions |
| LOA |
38.2 |
38.2 |
39.4 |
40.4 |
44.8 |
| LWL |
33.3 |
32.8 |
33.1 |
34.5 |
36.4 |
| Beam |
12.8 |
12.8 |
13.1 |
13.5 |
13.6 |
| Displacement |
14 |
16 |
17 |
19 |
20 |
| Ballast |
5 |
5 |
6 |
6 |
7 |
| Sail Area |
630 |
667 |
720 |
754 |
815 |
| Performance |
| SA/Disp |
17.1 |
16.4 |
17.3 |
16.7 |
17.2 |
| Bal/Disp |
36.2 |
33.3 |
35.3 |
35.2 |
33.7 |
| Comfort |
21.2 |
24.7 |
— |
25.8 |
25.5 |
| Capsize |
2.11 |
2.01 |
— |
2.01 |
1.97 |
| Hull Speed |
7.7 |
7.7 |
— |
7.9 |
8.1 |