Propeller Calc vs BoatAlarm

This calculator can determine pitch, gear ratio, RPM, propeller slip and speed parameters. Enter any four variables, and it will calculate the fifth. Use the toggle switch to choose which field to calculate. Pitch is the theoretical forward movement for one complete turn of the propeller. Every inch of the boat in contact with the water induces drag. Therefore, the distance travelled differs since the propeller is "slipping" behind the theoretical distance it should travel with each rotation. The difference between theory and reality is called slip. Depending on your application, slip typically ranges between 5% and 20%. A lower number is only sometimes what you are after. Slip of a prop changes with operating conditions and is not a direct measure of efficiency. Please consult professionals for guidance. Happy powerboating

BoatAlarm helps you keep track of current reports on the water. On the interactive map, you can see community reports about potential hazards, obstacles and relevant observations nearby. Features: - Community reports on the map - Create your own reports - View reports near you - Forum and exchange with the community - Personalized profile - Speed display with Premium - Top speed display with Premium - Weather information with temperature, wind direction and wind speed with Premium - Waterway name on the map as a Premium beta feature - New Premium design for a more modern app experience - Push notifications for relevant alerts with Premium - Ad-free use with Premium Create your own profile and become part of the community. BoatAlarm is built on users sharing observations and helping each other stay informed. BoatAlarm is not an official warning, emergency, rescue or navigation service. In dangerous situations, please contact the responsible official authorities. BoatAlarm Premium is available as a monthly or yearly subscription. The monthly subscription runs for 1 month, the yearly subscription runs for 1 year. Payment is handled through your Apple Account. The subscription renews automatically unless canceled at least 24 hours before the end of the current period. You can manage or cancel your subscription at any time in your App Store account settings. Privacy policy, terms and conditions, and terms of use are available in the app.