19″ Pitch × 16″ Diameter at 4000 RPM
This page evaluates a 19-inch pitch, 16-inch diameter propeller turning at 4000 RPM. Theoretical speed comes from the standard propulsion formula (pitch × RPM) ÷ (gear ratio × 1215.2). Slip ranges are empirical estimates that scale with the pitch-to-diameter ratio: over-pitched propellers slip more under heavy load, under-pitched propellers over-rev and waste fuel. Treat the numbers as a sizing checkpoint, then confirm with on-water WOT trials.
| Metric | Value |
|---|---|
| Theoretical speed at WOT | 41.69 knots |
| Theoretical speed at half throttle | 20.85 knots |
| Pitch-to-diameter ratio | 1.19 (19/16) |
| Assumed gear ratio | 1.50:1 |
| Expected slip (light load, hp-matched) | 12.0% |
| Expected slip (heavy load / over-pitched) | 22.0% |
At 4000 RPM the 41.69-knot theoretical top end places this combination in the high-performance / racing regime. The speed-biased (light runabout, RIB, performance fishing) pitch profile, paired with the high-rev WOT band, suits it best for the use cases above. If your boat tops out far below 41.69 knots at WOT, expect slip closer to the heavy-load figure or worse.
Notes & assumptions: gear ratio fixed at 1.5:1 — re-run with your actual ratio if it differs. Slip estimates assume a clean bottom, a hp-matched engine, and steady-state load; cavitation, fouling, or over-loading will push slip higher. Half-throttle speeds are linear projections, not measured curves.