classic RC motor launch boat, 723mm

thingiverse

Radio controlled motor launch, based on plans of a 1926 motor launch by John Hacker, scaled down for printing in six sections. The original boat was a 25 feet motor boat powered by a 150 HP engine. To replicate this design, the model is 723 mm long and requires a 140W motor (2830 750Kv brushless), 1.8Ah 3S battery, and a low profile servo for the rudder. With this power combination, it achieves scale speed on the water. Watch it in action: https://vimeo.com/251072600 Scaling up or down would be possible but tricky due to hard-coded scripts that rely on specific dimensions. Important variables are located at the top of each script, but their precedence isn't always logical. Due to file type restrictions on Thingiverse, not all files can be uploaded. The ribs and keel line were created using minimal free plans available, then smoothed with X-splines taken from a mathematical manuscript. These curves were converted into a solid 3D object using a custom gawk script. Continuous rib+keel points allowed for more continuous curves from bow to stern, which were stitched together to form an initial hull shape. The full build description and all original scripts can be found on my project page: http://abatis.org.uk/boatpage. After four days of testing on the water, various rudder sizes and propeller sizes have been tried. With this power combination, it's about as fast as it can go. I've also concluded that there are no major design flaws, but printing it with fewer than three perimeters is recommended for optimal performance.