The Shannon 38 is moderately powered for comfortable coastal cruising, with a steady, comfortable ride offshore, 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 30.8′, the Shannon 38 tops out around 7.4 knots in displacement mode — after that, the bow wave outruns the hull and resistance climbs steeply.
1.34 × √30.8′ LWL = 7.4 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
159s/nm
Typical cruiser — designed for comfort and ease, not podium finishes.
SA / Displacement
16.1
Moderate sail power — a capable coastal cruiser, not overpowered.
Comfort Ratio
33.6
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
33.6
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 38 sits on the PHRF handicap spectrum — lower numbers mean faster boats.
Racer 0–90
Cruiser/Racer 90–150
Cruiser 150–210
Sabre 38
114s/nm
Shannon 38
159s/nm
Typical cruiser — designed for comfort and ease, not podium finishes.
Shannon 37
195s/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° |
2.9 |
3.7 |
4.1 |
4.3 |
| Close Reach60° |
3.5 |
4.4 |
4.9 |
5.1 |
| Beam Reach90° |
4.3 |
5.4 |
6.1 |
6.3 |
| Broad Reach120–135° |
4.0 |
5.0 |
5.6 |
5.8 |
| Run150–180° |
3.2 |
4.0 |
4.5 |
4.7 |
These are simplified estimates based on hull speed (7.4 kts),
SA/D (16.1), 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 38 — 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 38.
|
Shannon 38 |
Bristol Channel Cutter |
Najad 37 |
Pacific 38 |
Sabre 38 |
Shannon 37 |
| Dimensions |
| LOA |
37.8 |
37.8 |
37.7 |
37.7 |
37.8 |
37.8 |
| LWL |
30.8 |
26.3 |
31.8 |
30.5 |
31.2 |
30.8 |
| Beam |
11.5 |
10.1 |
11.5 |
11.1 |
11.5 |
11.5 |
| Displacement |
18 |
14 |
19 |
16 |
15 |
17 |
| Ballast |
6 |
4 |
8 |
7 |
6 |
6 |
| Sail Area |
703 |
673 |
600 |
— |
— |
751 |
| Performance |
| PHRF |
159 |
— |
— |
— |
114 |
195 |
| SA/Disp |
16.1 |
18.6 |
13.2 |
— |
— |
17.9 |
| Bal/Disp |
— |
32.9 |
— |
43.5 |
42.1 |
— |
| Comfort |
33.6 |
33.6 |
35.4 |
— |
— |
31.8 |
| Capsize |
1.74 |
1.68 |
1.70 |
— |
— |
1.78 |
| Hull Speed |
7.4 |
6.9 |
7.6 |
— |
— |
7.4 |