The Dehler 31 is well-powered with enough sail area to move in light air, with a quick, snappy motion best suited to day sailing, designed for cruising comfort rather than racing.
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 24.3′, the Dehler 31 tops out around 6.6 knots in displacement mode — after that, the bow wave outruns the hull and resistance climbs steeply.
1.34 × √24.3′ LWL = 6.6 kts
Performance Ratios
Racing handicap, sail-carrying power, stability and comfort — and what each one actually tells you about a day on the water.
PHRF Rating
162s/nm
Typical cruiser — designed for comfort and ease, not podium finishes.
SA / Displacement
19.3
Powerful cruiser/racer — quick in light air, reef early when it pipes up.
Comfort Ratio
18.9
Quick, snappy motion — better for day sails and racing than long passages.
Capsize Screening
2.12
Above the 2.0 offshore threshold — best suited for coastal and protected waters.
Pounds/Inch Immersion
882lbs
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
18.9
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
2.12
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
PHRF Fleet Position
Where the Dehler 31 sits on the PHRF handicap spectrum — lower numbers mean faster boats.
Racer 0–90
Cruiser/Racer 90–150
Cruiser 150–210
Noelex 30
119s/nm
Dehler 31
162s/nm
Typical cruiser — designed for comfort and ease, not podium finishes.
Catalina 309
167s/nm
Dufour 31
168s/nm
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° |
2.8 |
3.5 |
4.0 |
4.1 |
| Close Reach60° |
3.4 |
4.3 |
4.8 |
5.0 |
| Beam Reach90° |
4.2 |
5.3 |
5.9 |
6.1 |
| Broad Reach120–135° |
3.8 |
4.9 |
5.4 |
5.7 |
| Run150–180° |
3.1 |
3.9 |
4.3 |
4.5 |
These are simplified estimates based on hull speed (6.6 kts),
SA/D (19.3), 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 Dehler 31 — based on sail area, ballast, and displacement characteristics.
Ghost
Sweet Spot
Reef
Heavy
0–6 kts
6–18 kts
18–26 kts
26+ kts
Ghosting
0–6 kts
Light air, motor-sailing likely. Need patience and a light genoa.
Sweet Spot
6–18 kts
Comfortable under full sail. Best speed-to-comfort ratio.
Time to Reef
18–26 kts
Time to shorten sail. Reef the main, swap to a working jib.
Heavy Weather
26+ 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 Dehler 31.
|
Dehler 31 |
Catalina 309 |
Dufour 31 |
Farr 30 Mumm 30 |
Hallberg Rassy 312 |
Noelex 30 |
| Dimensions |
| LOA |
30.8 |
30.8 |
30.8 |
30.9 |
30.9 |
30.9 |
| LWL |
24.3 |
26.0 |
23.0 |
27.6 |
25.3 |
26.8 |
| Beam |
10.2 |
11.0 |
10.5 |
10.1 |
10.1 |
9.4 |
| Displacement |
7 |
9 |
9 |
4 |
10 |
4 |
| Ballast |
2 |
3 |
3 |
1 |
4 |
1 |
| Sail Area |
443 |
452 |
395 |
504 |
484 |
410 |
| Performance |
| PHRF |
162 |
167 |
168 |
— |
— |
119 |
| SA/Disp |
19.3 |
16.4 |
14.0 |
29.4 |
15.9 |
25.6 |
| Bal/Disp |
— |
41.3 |
38.5 |
43.8 |
— |
31.4 |
| Comfort |
18.9 |
21.1 |
25.5 |
11.3 |
28.5 |
11.5 |
| Capsize |
2.12 |
2.10 |
1.98 |
2.44 |
1.83 |
2.34 |
| Hull Speed |
6.6 |
6.8 |
6.4 |
7.0 |
6.7 |
6.9 |