The Grampian 30 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 25.5′, the Grampian 30 tops out around 6.8 knots in displacement mode — after that, the bow wave outruns the hull and resistance climbs steeply.
1.34 × √25.5′ LWL = 6.8 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
192s/nm
Typical cruiser — designed for comfort and ease, not podium finishes.
SA / Displacement
16.3
Moderate sail power — a capable coastal cruiser, not overpowered.
Ballast / Displacement
45.0%
Race-oriented ballast ratio — very stiff and powerful.
Displacement / Length
232
Moderate — a good balance of speed and load-carrying ability.
Comfort Ratio
24.7
Acceptable coastal comfort — fine for weekends, notice the chop offshore.
Capsize Screening
1.86
Below the 2.0 offshore threshold — acceptable for ocean passages.
SA/Disp (Calculated)
14.9
Computed from measured I/J/P/E rather than reported sail area.
Pounds/Inch Immersion
866lbs
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
24.7
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
1.86
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 Grampian 30 sits on the PHRF handicap spectrum — lower numbers mean faster boats.
Cruiser/Racer 90–150
Cruiser 150–210
Heavy Cruiser 210–300
Seidelmann 30
162s/nm
San Juan 30
168s/nm
Carter 30
174s/nm
Pearson 30
174s/nm
Grampian 30
192s/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 |
3.3 |
3.7 |
3.9 |
| Close Reach60° |
3.2 |
4.0 |
4.5 |
4.7 |
| Beam Reach90° |
3.9 |
4.9 |
5.5 |
5.8 |
| Broad Reach120–135° |
3.6 |
4.6 |
5.1 |
5.3 |
| Run150–180° |
2.9 |
3.7 |
4.1 |
4.3 |
These are simplified estimates based on hull speed (6.8 kts),
SA/D (16.3), 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 Grampian 30 — based on sail area, ballast, and displacement characteristics.
Ghost
Sweet Spot
Reef
Heavy
0–7 kts
7–22 kts
22–32 kts
32+ kts
Ghosting
0–7 kts
Light air, motor-sailing likely. Need patience and a light genoa.
Sweet Spot
7–22 kts
Comfortable under full sail. Best speed-to-comfort ratio.
Time to Reef
22–32 kts
Time to shorten sail. Reef the main, swap to a working jib.
Heavy Weather
32+ 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 Grampian 30.
|
Grampian 30 |
Carter 30 |
Pearson 30 |
San Juan 30 |
Scampi 30 4 |
Seidelmann 30 |
| Dimensions |
| LOA |
29.8 |
29.8 |
29.8 |
29.9 |
29.8 |
29.8 |
| LWL |
25.5 |
23.0 |
25.0 |
23.7 |
23.0 |
25.0 |
| Beam |
9.5 |
10.1 |
9.5 |
10.1 |
9.8 |
12.0 |
| Displacement |
8 |
7 |
8 |
7 |
7 |
9 |
| Ballast |
3 |
2 |
3 |
3 |
2 |
4 |
| Sail Area |
425 |
384 |
445 |
402 |
374 |
— |
| Performance |
| PHRF |
192 |
174 |
174 |
168 |
— |
162 |
| SA/Disp |
16.3 |
16.4 |
17.4 |
17.3 |
16.0 |
— |
| Bal/Disp |
45.0 |
40.8 |
42.8 |
— |
— |
47.9 |
| Comfort |
24.7 |
20.8 |
24.3 |
20.2 |
21.4 |
— |
| Capsize |
1.86 |
2.08 |
1.88 |
2.09 |
2.03 |
— |
| Hull Speed |
6.8 |
6.4 |
6.7 |
6.5 |
6.4 |
— |