The Oyster 745 is well-powered with enough sail area to move in light air, with a gentle bluewater motion.
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 65.7′, the Oyster 745 tops out around 10.9 knots in displacement mode — after that, the bow wave outruns the hull and resistance climbs steeply.
1.34 × √65.7′ LWL = 10.9 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
19.9
Powerful cruiser/racer — quick in light air, reef early when it pipes up.
Comfort Ratio
51.9
Very comfortable in a seaway — a genuine bluewater motion.
Capsize Screening
1.58
Below the 2.0 offshore threshold — acceptable for ocean passages.
Pounds/Inch Immersion
4lbs
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
51.9
Very comfortable in a seaway — a genuine bluewater motion.
Under 20 — Snappy, racing motion
20–30 — Acceptable coastal
30–40 — Good offshore comfort
Over 40 — Very comfortable offshore
Capsize Screening Formula
1.58
Below the 2.0 offshore threshold — acceptable for ocean passages.
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° |
4.7 |
5.9 |
6.6 |
6.9 |
| Close Reach60° |
5.7 |
7.2 |
8.0 |
8.3 |
| Beam Reach90° |
7.0 |
8.8 |
9.8 |
10.2 |
| Broad Reach120–135° |
6.4 |
8.1 |
9.1 |
9.5 |
| Run150–180° |
5.1 |
6.5 |
7.3 |
7.6 |
These are simplified estimates based on hull speed (10.9 kts),
SA/D (19.9), 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 Oyster 745 — 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 Oyster 745.
|
Oyster 745 |
Baltic 73 |
Cnb 78 |
Hallberg Rassy 69 |
Oyster 675 |
Swan 80 2 S |
| Dimensions |
| LOA |
74.6 |
73.2 |
78.5 |
72.9 |
69.1 |
82.3 |
| LWL |
65.7 |
60.7 |
72.8 |
64.6 |
60.1 |
72.8 |
| Beam |
19.4 |
18.0 |
20.0 |
19.3 |
18.5 |
20.0 |
| Displacement |
118 |
77 |
105 |
102 |
82 |
79 |
| Ballast |
— |
29 |
27 |
39 |
— |
39 |
| Sail Area |
3 |
2 |
3 |
2 |
— |
3 |
| Performance |
| SA/Disp |
19.9 |
22.0 |
23.6 |
17.7 |
— |
28.9 |
| Bal/Disp |
— |
38.6 |
26.3 |
38.9 |
— |
— |
| Comfort |
51.9 |
39.3 |
40.5 |
45.8 |
— |
30.1 |
| Capsize |
1.58 |
1.70 |
1.70 |
1.66 |
— |
1.86 |
| Hull Speed |
10.9 |
10.4 |
11.4 |
10.8 |
— |
11.4 |