The Csy 51 is moderately powered for comfortable coastal cruising, with a steady, comfortable ride offshore, and respectable in club 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 42.3′, the Csy 51 tops out around 8.7 knots in displacement mode — after that, the bow wave outruns the hull and resistance climbs steeply.
1.34 × √42.3′ LWL = 8.7 kts
Performance Ratios
Racing handicap, sail-carrying power, stability and comfort — and what each one actually tells you about a day on the water.
PHRF Rating
108s/nm
Cruiser/racer — competitive in club racing, comfortable cruising.
SA / Displacement
16.2
Moderate sail power — a capable coastal cruiser, not overpowered.
Ballast / Displacement
46.6%
Race-oriented ballast ratio — very stiff and powerful.
Displacement / Length
207
Moderate — a good balance of speed and load-carrying ability.
Comfort Ratio
32.7
Good offshore comfort — steady enough for multi-day passages.
Capsize Screening
1.84
Below the 2.0 offshore threshold — acceptable for ocean passages.
Pounds/Inch Immersion
2lbs
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
32.7
Good offshore comfort — steady enough for multi-day passages.
Under 20 — Snappy, racing motion
20–30 — Acceptable coastal
30–40 — Good offshore comfort
Over 40 — Very comfortable offshore
Capsize Screening Formula
1.84
Below the 2.0 offshore threshold — acceptable for ocean passages.
Under 2.0 — Acceptable for offshore
Over 2.0 — Coastal / protected waters
PHRF Fleet Position
Where the Csy 51 sits on the PHRF handicap spectrum — lower numbers mean faster boats.
Racer 0–90
Cruiser/Racer 90–150
Cruiser 150–210
Bristol 51
69s/nm
Endeavour 51
75s/nm
Valiant 50
102s/nm
Csy 51
108s/nm
Cruiser/racer — competitive in club racing, comfortable cruising.
Shannon 50
117s/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° |
3.4 |
4.3 |
4.8 |
5.0 |
| Close Reach60° |
4.1 |
5.2 |
5.8 |
6.0 |
| Beam Reach90° |
5.0 |
6.4 |
7.1 |
7.4 |
| Broad Reach120–135° |
4.6 |
5.9 |
6.6 |
6.8 |
| Run150–180° |
3.7 |
4.7 |
5.2 |
5.5 |
These are simplified estimates based on hull speed (8.7 kts),
SA/D (16.2), 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 Csy 51 — based on sail area, ballast, and displacement characteristics.
Ghost
Sweet Spot
Reef
Heavy
0–7 kts
7–22 kts
22–32 kts
32+ kts
Ghosting
0–7 kts
Light air, motor-sailing likely. Need patience and a light genoa.
Sweet Spot
7–22 kts
Comfortable under full sail. Best speed-to-comfort ratio.
Time to Reef
22–32 kts
Time to shorten sail. Reef the main, swap to a working jib.
Heavy Weather
32+ 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 Csy 51.
|
Csy 51 |
Bristol 51 |
Endeavour 51 |
Little Harbor 51 |
Shannon 50 |
Valiant 50 |
| Dimensions |
| LOA |
51.0 |
51.1 |
51.0 |
50.6 |
50.9 |
50.7 |
| LWL |
42.3 |
42.0 |
42.3 |
41.0 |
42.8 |
40.3 |
| Beam |
15.0 |
15.2 |
15.0 |
15.3 |
14.3 |
13.8 |
| Displacement |
35 |
43 |
37 |
45 |
39 |
35 |
| Ballast |
16 |
19 |
17 |
18 |
15 |
11 |
| Sail Area |
1 |
1,200 |
1,078 |
1 |
1 |
— |
| Performance |
| PHRF |
108 |
69 |
75 |
— |
117 |
102 |
| SA/Disp |
16.2 |
15.5 |
15.6 |
15.3 |
17.1 |
— |
| Bal/Disp |
46.6 |
43.5 |
46.8 |
— |
39.7 |
31.0 |
| Comfort |
32.7 |
40.4 |
34.6 |
42.8 |
38.8 |
— |
| Capsize |
1.84 |
1.73 |
1.80 |
1.71 |
1.68 |
— |
| Hull Speed |
8.7 |
8.7 |
8.7 |
8.6 |
8.8 |
— |