The idea behind the Tugboat was to create a functional mechanism with a certain spice that would make it both down-to-earth and interesting. The Tugboat is driven by a rubber-band motor powered by the tension of the rubber connected with a bearing. The reduction gear transfers energy to the drive wheel and further to the asymmetrical wheel pair. The pendulum slows and evens the motion of the tugboat. The asymmetry of the wheel pair grants the model its unique way of moving, imitating a boat rocking on the waves, while the working pendulum creates a specific noise similar to one produced by the real-life diesel motor many boats are equipped with.
The winding key on the drive wheel is blocked by a ratchet gear. There are two control levers, one of which stops the mechanism and the other launches it – stop and start lever correspondingly. Use two ropes with hooks to hook up and transport small freight – wheeled models or a paper boat. Your Tugboat will run from 1.5 to 3 meters (5-10 ft) depending on the type of surface.
Like all other Ugears models, this mechanical model kit comes with step-by-step, full-color, truly easy to follow instructions and requires neither glue nor special tools to be fully assembled into functional Tugboat.

Ugears "Tugboat Kit" I DIY Self-Assembly Mechanical Kits For Teens and Adults