App Support

Marine Prop Slip

Marine Prop Slip Calc is a local-first field calculator for prop slip, theoretical speed, required pitch math, and local sea-trial notes.

What does the app calculate?

The app calculates:

prop slip percentage from RPM, gear ratio, pitch, and actual boat speed
theoretical speed from RPM, gear ratio, and pitch
required pitch from RPM, gear ratio, target speed, and assumed slip
local saved setups and sea-trial notes for repeat comparisons

Which inputs does the app use?

Version 1.0 supports:

engine RPM
gear ratio
propeller pitch
actual boat speed
target boat speed
assumed slip percentage
mph, knots, and km/h workflows

What does "prop slip" mean?

Prop slip is the difference between theoretical speed and actual speed. It helps show how far real-world boat performance is from the ideal no-slip calculation.

Does the app use live monitoring or connected engine data?

No. Version 1.0 is manual entry only. It does not connect to onboard engine data or other live monitoring sources.

Does the app recommend a specific propeller or brand?

No. Marine Prop Slip Calc is a math tool, not a prop recommendation engine or brand catalog.

Why are theoretical speed and actual speed different?

Real boats do not run at zero slip. Load, trim, hull condition, prop design, water conditions, tach accuracy, and speed-source accuracy can all change the real result.

Are the results guaranteed?

No. Use the app as a starting point for troubleshooting and planning. Always confirm actual on-water performance before buying or changing hardware.

Are my values synced anywhere?

No. Version 1.0 has no account system and no cloud sync.

Can I keep sea-trial notes in the app?

Yes. Version 1.0 can keep local saves and sea-trial notes on the current device so you can compare repeat runs without exporting data to a server.

Contact

Support email: yangguangwin@icloud.com