The Hms 18 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 16.8′, the Hms 18 tops out around 5.5 knots in displacement mode — after that, the bow wave outruns the hull and resistance climbs steeply.
1.34 × √16.8′ 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.
SA / Displacement
18.5
Powerful cruiser/racer — quick in light air, reef early when it pipes up.
Ballast / Displacement
30.2%
Typical cruising ballast — balanced stability and motion underway.
Displacement / Length
116
Ultralight — responsive and fast, but carries less stores.
Comfort Ratio
7.5
Quick, snappy motion — better for day sails and racing than long passages.
Capsize Screening
2.81
Above the 2.0 offshore threshold — best suited for coastal and protected waters.
Pounds/Inch Immersion
449lbs
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
7.5
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
2.81
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 Hms 18 sits on the PHRF handicap spectrum — lower numbers mean faster boats.
Cruiser 150–210
Heavy Cruiser 210–300
Oday 19
220s/nm
Starwind 19
288s/nm
Windrose 18
288s/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° |
2.3 |
2.9 |
3.2 |
3.3 |
| Close Reach60° |
2.8 |
3.5 |
3.9 |
4.1 |
| Beam Reach90° |
3.4 |
4.3 |
4.8 |
5.2 |
| Broad Reach120–135° |
3.1 |
3.9 |
4.4 |
4.8 |
| Run150–180° |
2.5 |
3.2 |
3.5 |
3.7 |
These are simplified estimates based on hull speed (5.5 kts),
SA/D (18.5), 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 Hms 18 — based on sail area, ballast, and displacement characteristics.
Ghost
Sweet Spot
Reef
Heavy
0–6 kts
6–18 kts
18–26 kts
26+ kts
Ghosting
0–6 kts
Light air, motor-sailing likely. Need patience and a light genoa.
Sweet Spot
6–18 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 Hms 18.
|
Hms 18 |
Com Pac 19 |
Oday 19 |
Starwind 19 |
Typhoon 18 Daysailer |
Windrose 18 |
| Dimensions |
| LOA |
18.8 |
19.0 |
19.0 |
18.6 |
18.5 |
18.5 |
| LWL |
16.8 |
16.3 |
16.7 |
15.6 |
13.5 |
15.8 |
| Beam |
7.5 |
7.0 |
7.8 |
7.5 |
6.3 |
7.0 |
| Displacement |
1 |
2 |
2 |
1 |
2 |
1 |
| Ballast |
370 |
800 |
300 |
395 |
900 |
400 |
| Sail Area |
132 |
145 |
179 |
— |
156 |
— |
| Performance |
| PHRF |
— |
— |
220 |
288 |
— |
288 |
| SA/Disp |
18.5 |
14.7 |
17.9 |
— |
15.8 |
— |
| Bal/Disp |
30.2 |
40.0 |
— |
29.3 |
— |
26.7 |
| Comfort |
7.5 |
13.5 |
11.9 |
— |
17.8 |
— |
| Capsize |
2.81 |
2.22 |
2.45 |
— |
2.00 |
— |
| Hull Speed |
5.5 |
5.4 |
5.5 |
— |
4.9 |
— |