The Clipper Marine 21 is well-powered with enough sail area to move in light air, with a quick, snappy motion best suited to day sailing.
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 16.7′, the Clipper Marine 21 tops out around 5.5 knots in displacement mode — after that, the bow wave outruns the hull and resistance climbs steeply.
1.34 × √16.7′ LWL = 5.5 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
270s/nm
Heavy or slow cruiser — all about the journey, not the elapsed time.
SA / Displacement
20.8
Powerful cruiser/racer — quick in light air, reef early when it pipes up.
Ballast / Displacement
22.8%
Light ballast — tends to be tender; reef earlier than the numbers suggest.
Displacement / Length
173
Moderate — a good balance of speed and load-carrying ability.
Comfort Ratio
11.1
Quick, snappy motion — better for day sails and racing than long passages.
Capsize Screening
2.39
Above the 2.0 offshore threshold — best suited for coastal and protected waters.
Pounds/Inch Immersion
432lbs
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
11.1
Quick, snappy motion — better for day sails and racing than long passages.
Under 20 — Snappy, racing motion
20–30 — Acceptable coastal
30–40 — Good offshore comfort
Over 40 — Very comfortable offshore
Capsize Screening Formula
2.39
Above the 2.0 offshore threshold — best suited for coastal and protected waters.
Under 2.0 — Acceptable for offshore
Over 2.0 — Coastal / protected waters
PHRF Fleet Position
Where the Clipper Marine 21 sits on the PHRF handicap spectrum — lower numbers mean faster boats.
Cruiser 150–210
Heavy Cruiser 210–300
Precision 21
243s/nm
Venture 21
252s/nm
Macgregor 21
263s/nm
Aquarius 21
267s/nm
Clipper Marine 21
270s/nm
Heavy or slow cruiser — all about the journey, not the elapsed time.
Islander 21
279s/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° |
2.4 |
3.1 |
3.4 |
3.6 |
| Close Reach60° |
2.9 |
3.7 |
4.1 |
4.3 |
| Beam Reach90° |
3.6 |
4.5 |
5.1 |
5.5 |
| Broad Reach120–135° |
3.3 |
4.2 |
4.7 |
5.1 |
| Run150–180° |
2.6 |
3.3 |
3.7 |
3.9 |
These are simplified estimates based on hull speed (5.5 kts),
SA/D (20.8), 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 Clipper Marine 21 — based on sail area, ballast, and displacement characteristics.
Ghost
Sweet Spot
Reef
Heavy
0–6 kts
6–16 kts
16–24 kts
24+ kts
Ghosting
0–6 kts
Light air, motor-sailing likely. Need patience and a light genoa.
Sweet Spot
6–16 kts
Comfortable under full sail. Best speed-to-comfort ratio.
Time to Reef
16–24 kts
Time to shorten sail. Reef the main, swap to a working jib.
Heavy Weather
24+ 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 Clipper Marine 21.
|
Clipper Marine 21 |
Aquarius 21 |
Islander 21 |
Macgregor 21 |
Precision 21 |
Venture 21 |
| Dimensions |
| LOA |
20.9 |
21.0 |
20.8 |
21.0 |
20.8 |
21.0 |
| LWL |
16.7 |
18.3 |
18.0 |
18.5 |
17.5 |
18.5 |
| Beam |
7.3 |
7.8 |
7.8 |
6.8 |
8.3 |
6.8 |
| Displacement |
1 |
1 |
1 |
1 |
1 |
1 |
| Ballast |
410 |
665 |
1 |
400 |
600 |
400 |
| Sail Area |
192 |
163 |
215 |
— |
203 |
— |
| Performance |
| PHRF |
270 |
267 |
279 |
263 |
243 |
252 |
| SA/Disp |
20.8 |
17.0 |
22.1 |
— |
21.4 |
— |
| Bal/Disp |
22.8 |
35.0 |
51.3 |
34.0 |
32.0 |
26.7 |
| Comfort |
11.1 |
9.9 |
10.3 |
— |
9.4 |
— |
| Capsize |
2.39 |
2.53 |
2.51 |
— |
2.68 |
— |
| Hull Speed |
5.5 |
5.7 |
5.7 |
— |
5.6 |
— |