The Offshore 45 Tanton is aggressively canvassed for its weight, 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 39.4′, the Offshore 45 Tanton tops out around 8.4 knots in displacement mode — after that, the bow wave outruns the hull and resistance climbs steeply.
1.34 × √39.4′ LWL = 8.4 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
22.3
Performance-oriented — carries a lot of canvas for its weight.
Ballast / Displacement
35.8%
Typical cruising ballast — balanced stability and motion underway.
Displacement / Length
189
Moderate — a good balance of speed and load-carrying ability.
Comfort Ratio
30.0
Acceptable coastal comfort — fine for weekends, notice the chop offshore.
Capsize Screening
1.85
Below the 2.0 offshore threshold — acceptable for ocean passages.
SA/Disp (Calculated)
7.9
Computed from measured I/J/P/E rather than reported sail area.
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
30.0
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
1.85
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 Offshore 45 Tanton sits on the PHRF handicap spectrum — lower numbers mean faster boats.
Racer 0–90
Cruiser/Racer 90–150
Cruiser 150–210
Freedom 45 Cc
99s/nm
Herreshoff 45 Cat Ketch
114s/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° |
3.9 |
4.9 |
5.4 |
5.7 |
| Close Reach60° |
4.7 |
5.9 |
6.6 |
6.9 |
| Beam Reach90° |
5.7 |
7.2 |
8.1 |
8.8 |
| Broad Reach120–135° |
5.3 |
6.7 |
7.5 |
8.1 |
| Run150–180° |
4.2 |
5.3 |
6.0 |
6.2 |
These are simplified estimates based on hull speed (8.4 kts),
SA/D (22.3), 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 Offshore 45 Tanton — 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 Offshore 45 Tanton.
|
Offshore 45 Tanton |
Caliber 45 |
Freedom 45 Cc |
Hans Christian 45 |
Herreshoff 45 Cat Ketch |
Tanton 45 |
| Dimensions |
| LOA |
44.8 |
45.0 |
45.0 |
44.9 |
45.0 |
44.8 |
| LWL |
39.4 |
35.8 |
34.4 |
34.3 |
40.0 |
39.4 |
| Beam |
13.7 |
13.3 |
13.5 |
14.0 |
13.4 |
13.7 |
| Displacement |
25 |
29 |
22 |
37 |
18 |
25 |
| Ballast |
9 |
12 |
9 |
11 |
8 |
9 |
| Sail Area |
1 |
940 |
731 |
952 |
830 |
1 |
| Performance |
| PHRF |
— |
— |
99 |
— |
114 |
— |
| SA/Disp |
22.3 |
16.0 |
14.5 |
13.8 |
19.1 |
22.3 |
| Bal/Disp |
35.8 |
41.4 |
41.3 |
30.5 |
43.2 |
— |
| Comfort |
30.0 |
36.9 |
29.5 |
45.4 |
21.7 |
30.0 |
| Capsize |
1.85 |
1.74 |
1.90 |
1.68 |
2.03 |
1.85 |
| Hull Speed |
8.4 |
8.0 |
7.9 |
7.9 |
8.5 |
8.4 |