Spesifikasi Baling-Baling 15" × 15"
Rasio pitch 1.00: kecepatan teoritis pada 1.000–4.000 RPM
Overview
A 15-inch diameter by 15-inch pitch propeller produces a pitch-to-diameter ratio of 1.00, which falls into the speed-biased, high-revving bracket. The diameter sets the disc area that converts engine torque into thrust, while the pitch sets the theoretical distance the propeller advances per revolution. At 2,500 RPM through a 1.5:1 gearbox this combination posts a theoretical no-slip speed of 20.6 knots; at the 4,000 RPM upper trace the same prop reaches 32.9 knots, with real-world slip pulling those numbers down by 10–20 percent depending on hull loading and bottom condition.
Spesifikasi baling-baling
| Diameter | 15" |
|---|---|
| Pitch | 15" |
| Rasio pitch | 1.00 |
Kecepatan teoritis per RPM
| RPM | Kecepatan (slip 0%) | Kecepatan (slip 15%) |
|---|---|---|
| 1,000 | 8.2 | 7.0 |
| 1,500 | 12.3 | 10.5 |
| 2,000 | 16.5 | 14.0 |
| 2,500 | 20.6 | 17.5 |
| 3,000 | 24.7 | 21.0 |
| 3,500 | 28.8 | 24.5 |
| 4,000 | 32.9 | 28.0 |
Typical applications
The 15"×15" size is most commonly fitted to family runabouts, walkarounds, and 75–150 hp center consoles, where the speed-biased, high-revving pitch profile matches the planing performance window. Boats inside this class generally cruise between 20.6 and 32.9 knots on the speed chart above. High-RPM, high-pitch combinations are characteristic of light, planing hulls and performance fishing rigs. If your boat tops out far below the 32.9-knot theoretical figure, the propeller is over-pitched for your loaded weight and slip will climb toward the 15-percent column; if you over-rev past the engine's WOT range, the propeller is under-pitched and you should step up one or two inches of pitch.
Compared with adjacent sizes
Holding diameter at 15" and dropping pitch by two inches yields a lower top speed but quicker hole-shot and better load-carrying behaviour, which is why 15"×13" propellers are popular for heavy or family-loaded boats. Raising pitch by two inches to 15"×17" trades acceleration for roughly 2.7 knots of additional theoretical speed at the same RPM. Holding pitch at 15" and changing diameter shifts thrust area: a 14"×15" prop spins up easier on small engines, while 16"×15" needs a stiffer driveline but bites harder under load.
Sizing notes and assumptions
The speed table assumes a 1.5:1 gear reduction and the standard propulsion identity (pitch × RPM) ÷ (gear ratio × 1,215.2) to convert inches-per-minute into knots. Slip estimates of 0 percent (theoretical) and 15 percent (realistic cruising) bracket most clean-bottom planing hulls; expect higher slip on displacement vessels, fouled bottoms, or when towing. Always confirm propeller choice against the engine manufacturer's recommended WOT RPM window — landing inside the band protects the powerhead from lugging or over-revving and is the single biggest factor in long-term engine life.