Boatdiesel prop calculator alternative
Now that Boatdiesel is offline.
The Boatdiesel.com calculators have been offline since October 2024. Propbench does the same job in the browser, with engine and gearbox data built in, and adds outboards, sterndrives and saildrives.
Coming from Boatdiesel?
The numbers you used to enter, and where they go
Engine power and rated rpmPick the engine · power, rpm and torque curve from the database
Reduction gear ratioPick the gearbox and ratio
Waterline, displacement, hull typeBoat · length, weight, type
Current prop D × P, bladesYour prop today
Measured full-throttle rpm and speedSea trial · optional, sharpens the verdict
Compare
What is left since Boatdiesel went offline.
| Feature | Propbench | Free calculator sites | Pro desktop software | Maker selectors |
|---|---|---|---|---|
| Where it runs | Browser, phone, tablet | Browser | Installed desktop software | Browser |
| Boat types | Inboard, outboard, sterndrive, saildrive | Any, generic formulas | Prop trade, all types | Outboard and sterndrive |
| Engine and gearbox data | Built in | Enter by hand | [check] | Own engines |
| Which props it recommends | Any brand, neutral maths | No recommendation | Any | Own brand only |
| Price | Free for owners · shops from €99 / mo | Free | Quote-based | Free |
Questions
Straight answers.
Is Boatdiesel coming back?
We don't know. Its calculators have been offline since October 2024.
Will I get the same numbers?
Not exactly; the methods differ. Propbench prints every input and assumption with the result, so you can compare like for like.
Is it free?
Yes for boat owners. The free check, verdict and size ranges need no account.
Which methods does it use?
Wageningen B-series, Gerr and Crouch hull estimates, Keller and Burrill cavitation checks. Methods and accuracy.