15″ Pitch × 14″ Diameter at 3000 RPM
This page evaluates a 15-inch pitch, 14-inch diameter propeller turning at 3000 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 | 24.69 knots |
| Theoretical speed at half throttle | 12.34 knots |
| Pitch-to-diameter ratio | 1.07 (15/14) |
| Assumed gear ratio | 1.50:1 |
| Expected slip (light load, hp-matched) | 12.0% |
| Expected slip (heavy load / over-pitched) | 22.0% |
At 3000 RPM the 24.69-knot theoretical top end places this combination in the planing regime. The speed-biased (light runabout, RIB, performance fishing) pitch profile, paired with the mid-rev efficient band, suits it best for the use cases above. If your boat tops out far below 24.69 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.