The Kirby 30 is aggressively canvassed for its weight, with a quick, snappy motion best suited to day sailing, and respectable in club 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 23.5′, the Kirby 30 tops out around 6.5 knots in displacement mode — after that, the bow wave outruns the hull and resistance climbs steeply.
1.34 × √23.5′ LWL = 6.5 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
135s/nm
Cruiser/racer — competitive in club racing, comfortable cruising.
SA / Displacement
22.8
Performance-oriented — carries a lot of canvas for its weight.
Comfort Ratio
14.7
Quick, snappy motion — better for day sails and racing than long passages.
Capsize Screening
2.35
Above the 2.0 offshore threshold — best suited for coastal and protected waters.
Pounds/Inch Immersion
861lbs
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
14.7
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
2.35
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 Kirby 30 sits on the PHRF handicap spectrum — lower numbers mean faster boats.
Racer 0–90
Cruiser/Racer 90–150
Cruiser 150–210
Olson 29
99s/nm
Davidson 29
117s/nm
Kirby 30
135s/nm
Cruiser/racer — competitive in club racing, comfortable cruising.
X 302
146s/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° |
3.0 |
3.8 |
4.3 |
4.4 |
| Close Reach60° |
3.6 |
4.6 |
5.1 |
5.4 |
| Beam Reach90° |
4.5 |
5.7 |
6.3 |
6.5 |
| Broad Reach120–135° |
4.1 |
5.2 |
5.8 |
6.1 |
| Run150–180° |
3.3 |
4.2 |
4.7 |
4.9 |
These are simplified estimates based on hull speed (6.5 kts),
SA/D (22.8), 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 Kirby 30 — based on sail area, ballast, and displacement characteristics.
Ghost
Sweet Spot
Reef
Heavy
0–5 kts
5–16 kts
16–24 kts
24+ kts
Ghosting
0–5 kts
Light air, motor-sailing likely. Need patience and a light genoa.
Sweet Spot
5–16 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 Kirby 30.
|
Kirby 30 |
Cc 29 |
Davidson 29 |
First 29 Beneteau |
Olson 29 |
X 302 |
| Dimensions |
| LOA |
29.7 |
29.6 |
29.8 |
29.7 |
29.7 |
29.8 |
| LWL |
23.5 |
23.6 |
26.3 |
26.2 |
27.5 |
26.4 |
| Beam |
10.3 |
10.3 |
11.3 |
9.8 |
9.3 |
9.8 |
| Displacement |
5 |
7 |
7 |
7 |
3 |
7 |
| Ballast |
2 |
2 |
2 |
2 |
1 |
3 |
| Sail Area |
434 |
422 |
500 |
388 |
365 |
— |
| Performance |
| PHRF |
135 |
— |
117 |
— |
99 |
146 |
| SA/Disp |
22.8 |
17.7 |
21.7 |
17.0 |
24.9 |
— |
| Bal/Disp |
— |
36.0 |
33.8 |
31.4 |
— |
41.7 |
| Comfort |
14.7 |
20.4 |
16.0 |
19.2 |
10.1 |
— |
| Capsize |
2.35 |
2.11 |
2.34 |
2.04 |
2.44 |
— |
| Hull Speed |
6.5 |
6.5 |
6.9 |
6.9 |
7.0 |
— |