Hi Gabo thanks for the comprehensive reply Will try all this out. Instead of reversing RPM some sort of gear/clutch system to control direction of prop/thrust, jet planes use reverse thrust to slow down, and some large prop planes use this to reverse the a/c, maybe something for future ver. Thanks will test, although maneuvering a two engine tug might require a third hand . My aim is to be able to control having a joystick per engine. Agreed, this is using particles to generate rope, does not seem to affect performance that much. Cant get the wooden boat to react when I click on the buttons just moves forward. In any case I have not looked into this that much as I am using my own script for bow thrusters. Thanks will try this. So sectionheight would = the ships waterline? Maybe some sort of ILS at runways to create some sort of curve/spline which an a/c can follow as a glide path. Thanks for your help.