We came back to our place, where we put our Amethyst first time in to the sea water. Compare to weather in Prague (Czech), Pula (Croatia) has much enjoyable temperature to live in. Task was to get data on propeller RPM's versus speed. This is needed for internal navigation process. We are using GPS module to get speed with all telemetry recorded to log. This will give us basic output: how fast craft going when X RPM's are applied to the propeller.