The Discovery 79 Grampian is moderately powered for comfortable coastal cruising, 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 21.8′, the Discovery 79 Grampian tops out around 6.3 knots in displacement mode — after that, the bow wave outruns the hull and resistance climbs steeply.
1.34 × √21.8′ LWL = 6.2 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
17.2
Moderate sail power — a capable coastal cruiser, not overpowered.
Ballast / Displacement
45.1%
Race-oriented ballast ratio — very stiff and powerful.
Displacement / Length
221
Moderate — a good balance of speed and load-carrying ability.
Comfort Ratio
20.3
Acceptable coastal comfort — fine for weekends, notice the chop offshore.
Capsize Screening
1.94
Below the 2.0 offshore threshold — acceptable for ocean passages.
Pounds/Inch Immersion
647lbs
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
20.3
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
1.94
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 Discovery 79 Grampian sits on the PHRF handicap spectrum — lower numbers mean faster boats.
Cruiser 150–210
Heavy Cruiser 210–300
Capri 26 Catalina
213s/nm
Yankee 26
228s/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° |
2.5 |
3.2 |
3.5 |
3.7 |
| Close Reach60° |
3.0 |
3.8 |
4.3 |
4.5 |
| Beam Reach90° |
3.7 |
4.7 |
5.2 |
5.5 |
| Broad Reach120–135° |
3.4 |
4.3 |
4.8 |
5.1 |
| Run150–180° |
2.7 |
3.5 |
3.9 |
4.0 |
These are simplified estimates based on hull speed (6.3 kts),
SA/D (17.2), 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 Discovery 79 Grampian — 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 Discovery 79 Grampian.
|
Discovery 79 Grampian |
Capri 26 Catalina |
Centaur 26 Westerly |
Chrysler 26 Fk |
S2 80 B |
Yankee 26 |
| Dimensions |
| LOA |
26.0 |
26.0 |
26.0 |
26.0 |
26.0 |
26.0 |
| LWL |
21.8 |
22.5 |
21.3 |
22.0 |
21.4 |
20.7 |
| Beam |
8.3 |
9.1 |
8.4 |
8.0 |
8.0 |
8.7 |
| Displacement |
5 |
4 |
6 |
5 |
4 |
5 |
| Ballast |
2 |
1 |
2 |
2 |
1 |
2 |
| Sail Area |
318 |
268 |
324 |
257 |
282 |
— |
| Performance |
| PHRF |
— |
213 |
— |
— |
— |
228 |
| SA/Disp |
17.2 |
16.0 |
14.6 |
13.2 |
16.4 |
— |
| Bal/Disp |
45.1 |
37.5 |
41.8 |
43.6 |
— |
40.3 |
| Comfort |
20.3 |
15.2 |
26.7 |
23.0 |
19.5 |
— |
| Capsize |
1.94 |
2.22 |
1.79 |
1.82 |
1.93 |
— |
| Hull Speed |
6.3 |
6.4 |
6.2 |
6.3 |
6.2 |
— |