The Shannon 28 is moderately powered for comfortable coastal cruising, with acceptable motion comfort for coastal passages, 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 22.9′, the Shannon 28 tops out around 6.4 knots in displacement mode — after that, the bow wave outruns the hull and resistance climbs steeply.
1.34 × √22.9′ LWL = 6.4 kts
Performance Ratios
Racing handicap, sail-carrying power, stability and comfort — and what each one actually tells you about a day on the water.
PHRF Rating
204s/nm
Typical cruiser — designed for comfort and ease, not podium finishes.
SA / Displacement
17.1
Moderate sail power — a capable coastal cruiser, not overpowered.
Comfort Ratio
29.3
Acceptable coastal comfort — fine for weekends, notice the chop offshore.
Capsize Screening
1.81
Below the 2.0 offshore threshold — acceptable for ocean passages.
Pounds/Inch Immersion
778lbs
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
29.3
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
1.81
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 28 sits on the PHRF handicap spectrum — lower numbers mean faster boats.
Cruiser/Racer 90–150
Cruiser 150–210
Heavy Cruiser 210–300
Ranger 28
185s/nm
Sabre 28 1
186s/nm
Grampian 28
198s/nm
Shannon 28
204s/nm
Typical cruiser — designed for comfort and ease, not podium finishes.
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° |
2.6 |
3.2 |
3.6 |
3.8 |
| Close Reach60° |
3.1 |
3.9 |
4.4 |
4.6 |
| Beam Reach90° |
3.8 |
4.8 |
5.4 |
5.6 |
| Broad Reach120–135° |
3.5 |
4.4 |
5.0 |
5.2 |
| Run150–180° |
2.8 |
3.5 |
4.0 |
4.1 |
These are simplified estimates based on hull speed (6.4 kts),
SA/D (17.1), 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 28 — 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 28.
|
Shannon 28 |
Ericson 28 2 |
Grampian 28 |
Pearson 28 1975 80 |
Ranger 28 |
Sabre 28 1 |
| Dimensions |
| LOA |
28.0 |
28.0 |
28.0 |
28.0 |
28.0 |
28.0 |
| LWL |
22.9 |
23.3 |
24.5 |
24.0 |
21.7 |
22.8 |
| Beam |
9.5 |
10.0 |
9.5 |
9.3 |
9.6 |
9.0 |
| Displacement |
9 |
7 |
6 |
7 |
5 |
6 |
| Ballast |
3 |
3 |
3 |
3 |
2 |
2 |
| Sail Area |
470 |
411 |
— |
395 |
— |
391 |
| Performance |
| PHRF |
204 |
— |
198 |
— |
185 |
186 |
| SA/Disp |
17.1 |
17.2 |
— |
16.1 |
— |
17.3 |
| Bal/Disp |
— |
— |
44.4 |
45.0 |
55.0 |
42.0 |
| Comfort |
29.3 |
21.8 |
— |
24.9 |
— |
23.4 |
| Capsize |
1.81 |
2.05 |
— |
1.86 |
— |
1.89 |
| Hull Speed |
6.4 |
6.5 |
— |
6.6 |
— |
6.4 |