Knot (UK) to Millimeter per Second

The UK knot is a historical variation of the knot based on the British nautical mile (6,080 feet) rather than the international nautical mile (6,076.12 feet).

1 UK knot ≈ 1.853184 km/h = 0.5148 m/s. Slightly faster than the international knot (1.852 km/h).

To international knots: × 1.00064. To km/h: × 1.853. To m/s: × 0.5148.

None in modern use. Only relevant for interpreting historical British naval records.

The difference between UK and international knots is only 0.064% — barely noticeable but important for precise navigation.

Assuming all old British ship logs use the same knot as today — they don't, but the difference is tiny.

Historical only. Effectively identical to modern knot. Only matters for historical maritime research.

Millimeter per second measures distance in millimeters traveled in one second. Used for small-scale movements and precise measurements.

1 mm/s = 0.001 m/s = 0.0036 km/h = 0.06 m/min.

To m/s: ÷ 1,000. To cm/s: ÷ 10. To km/h: × 0.0036.

Vibration measurements (machinery typically 0.1–50 mm/s RMS), small motor speeds, precision linear actuators, and tape/film transport speeds.

Machinery vibration: >10 mm/s indicates problems. Seismic activity: 0.001–100 mm/s. CD/DVD read head: 1.2–1.4 mm/s linear velocity.

Confusing mm/s with cm/s (10× different) or m/s (1000× different).

1,000 mm/s = 1 m/s. Very common in vibration analysis. 10 mm/s RMS is a typical machinery vibration threshold.