The Alpha 48 is moderately powered for comfortable coastal cruising, with a gentle bluewater motion.
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 37.0′, the Alpha 48 tops out around 8.2 knots in displacement mode — after that, the bow wave outruns the hull and resistance climbs steeply.
1.34 × √37.0′ LWL = 8.2 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
15.7
Moderate sail power — a capable coastal cruiser, not overpowered.
Ballast / Displacement
27.9%
Light ballast — tends to be tender; reef earlier than the numbers suggest.
Displacement / Length
379
Heavy displacement — a slow, steady, seakindly hull.
Comfort Ratio
51.1
Very comfortable in a seaway — a genuine bluewater motion.
Capsize Screening
1.55
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
51.1
Very comfortable in a seaway — a genuine bluewater motion.
Under 20 — Snappy, racing motion
20–30 — Acceptable coastal
30–40 — Good offshore comfort
Over 40 — Very comfortable offshore
Capsize Screening Formula
1.55
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 Alpha 48 sits on the PHRF handicap spectrum — lower numbers mean faster boats.
Racer 0–90
Cruiser/Racer 90–150
Oyster 48 Lightwave
62s/nm
Swan 48 Ss
72s/nm
Tartan 48
80s/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° |
3.1 |
3.9 |
4.4 |
4.6 |
| Close Reach60° |
3.8 |
4.8 |
5.3 |
5.6 |
| Beam Reach90° |
4.6 |
5.9 |
6.5 |
6.8 |
| Broad Reach120–135° |
4.3 |
5.4 |
6.1 |
6.3 |
| Run150–180° |
3.4 |
4.3 |
4.8 |
5.0 |
These are simplified estimates based on hull speed (8.2 kts),
SA/D (15.7), 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 Alpha 48 — based on sail area, ballast, and displacement characteristics.
Ghost
Sweet Spot
Reef
Heavy
0–7 kts
7–18 kts
18–26 kts
26+ kts
Ghosting
0–7 kts
Light air, motor-sailing likely. Need patience and a light genoa.
Sweet Spot
7–18 kts
Comfortable under full sail. Best speed-to-comfort ratio.
Time to Reef
18–26 kts
Time to shorten sail. Reef the main, swap to a working jib.
Heavy Weather
26+ 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 Alpha 48.
|
Alpha 48 |
Christina 48 Hans Christian |
Clipper 48 Ketch Cheoy Lee |
Oyster 48 Lightwave |
Swan 48 Ss |
Tartan 48 |
| Dimensions |
| LOA |
48.0 |
47.9 |
47.9 |
48.0 |
47.9 |
48.0 |
| LWL |
37.0 |
40.3 |
34.0 |
41.7 |
37.3 |
36.0 |
| Beam |
13.6 |
13.5 |
13.0 |
14.3 |
13.6 |
14.0 |
| Displacement |
43 |
29 |
31 |
27 |
36 |
28 |
| Ballast |
12 |
11 |
13 |
11 |
14 |
— |
| Sail Area |
1 |
960 |
1 |
1 |
1 |
— |
| Performance |
| PHRF |
— |
— |
— |
62 |
72 |
80 |
| SA/Disp |
15.7 |
16.0 |
19.2 |
18.9 |
15.2 |
— |
| Bal/Disp |
27.9 |
— |
— |
— |
39.2 |
— |
| Comfort |
51.1 |
33.9 |
41.2 |
27.6 |
42.5 |
— |
| Capsize |
1.55 |
1.74 |
1.66 |
1.91 |
1.65 |
— |
| Hull Speed |
8.2 |
8.5 |
7.8 |
8.7 |
8.2 |
— |