Paddle boat with spring motor

I`ve adapted the excellent spring engine made by GZUMWALT (Wheelie, http://www.thingiverse.com/thing:452248 ) to create this paddles boat.
I just made some changes to obtain a better adaptation to the water environment;
The spring thickness has been reduced (-0,4mm) in order to have a less powerful engine, not necessary with a boat. This also let an increased autonomy and it’s easier to charge.
The thickness of the gears has been increased, the original version gave me some precision problems, probably due to my printer (actually I mount a 0,5 mm nozzle)
NB. The actual length of the boat is 220mm, and it has been a difficult task to print it on my OrdBot. In a future evolution I will try to reduce this dimension, bearing in mind that the weight of the motor is important.
Floatation tests have been very satisfactory and the boat was really appreciated by my daughter!
Update 14 July 2015: added new reduced hull (lenght 195 mm) tested successfully.

Please check also my new project, the Spring powered Catamaran (http://www.thingiverse.com/thing:1037341). Thanks