The Shannon 43 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 36.6′, the Shannon 43 tops out around 8.1 knots in displacement mode — after that, the bow wave outruns the hull and resistance climbs steeply.
1.34 × √36.6′ LWL = 8.1 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
141s/nm
Cruiser/racer — competitive in club racing, comfortable cruising.
SA / Displacement
16.2
Moderate sail power — a capable coastal cruiser, not overpowered.
Ballast / Displacement
37.0%
Typical cruising ballast — balanced stability and motion underway.
Displacement / Length
246
Moderate — a good balance of speed and load-carrying ability.
Comfort Ratio
35.4
Good offshore comfort — steady enough for multi-day passages.
Capsize Screening
1.74
Below the 2.0 offshore threshold — acceptable for ocean passages.
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
35.4
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
1.74
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 Shannon 43 sits on the PHRF handicap spectrum — lower numbers mean faster boats.
Racer 0–90
Cruiser/Racer 90–150
Cruiser 150–210
Ct 44
120s/nm
Shannon 43
141s/nm
Cruiser/racer — competitive in club racing, comfortable cruising.
Mason 43
146s/nm
Mason 44
146s/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° |
3.2 |
4.0 |
4.5 |
4.6 |
| Close Reach60° |
3.8 |
4.8 |
5.4 |
5.6 |
| Beam Reach90° |
4.7 |
5.9 |
6.6 |
6.9 |
| Broad Reach120–135° |
4.3 |
5.5 |
6.1 |
6.4 |
| Run150–180° |
3.5 |
4.4 |
4.9 |
5.1 |
These are simplified estimates based on hull speed (8.1 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 Shannon 43 — 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 Shannon 43.
|
Shannon 43 |
Ct 44 |
Hinckley 43 Mccurdy Rhodes |
Mason 43 |
Mason 44 |
Peterson 44 Cutter |
| Dimensions |
| LOA |
43.8 |
43.9 |
43.9 |
43.8 |
43.9 |
43.8 |
| LWL |
36.6 |
37.6 |
31.3 |
31.3 |
31.8 |
38.7 |
| Beam |
13.0 |
13.1 |
12.5 |
12.3 |
12.3 |
12.9 |
| Displacement |
27 |
20 |
24 |
25 |
27 |
30 |
| Ballast |
10 |
9 |
8 |
8 |
9 |
10 |
| Sail Area |
910 |
873 |
818 |
771 |
— |
865 |
| Performance |
| PHRF |
141 |
120 |
— |
146 |
146 |
— |
| SA/Disp |
16.2 |
18.9 |
15.8 |
14.5 |
— |
14.4 |
| Bal/Disp |
37.0 |
45.8 |
35.4 |
33.6 |
34.3 |
33.3 |
| Comfort |
35.4 |
25.7 |
36.6 |
39.2 |
— |
38.2 |
| Capsize |
1.74 |
1.93 |
1.74 |
1.68 |
— |
1.67 |
| Hull Speed |
8.1 |
8.2 |
7.5 |
7.5 |
— |
8.3 |