Like all vessels sharing our common architecture, the OpenCat consists of five modules, or components. The catamaran has two hulls instead of one, and these hulls need special connections (the fifth component).
The Open Waterbike 'prototype 0' functions as an architectural model for us. It has the structure typical for our boats, and we are developing from here onward.
Forward Tube Connection
The distinctive architectural element of the Open Waterbike 'prototype 0' is that the drive unit is mounted on the forward cross tube. This architecture can easily be adopted also for drive systems with a flexible shaft (flex-shaft drive).
It is simple and easy to build. In tests, it showed excellent results.
The forward cross tube, at the same time as carrying the vessel's propulsion system, also has a function as a structural (stabilizing) part, necessary with multihull boats. In the case of compact drive units sitting on the cross tube, a special feature is that the rider can swivel them up or down by foot (kick-up). The short video (upper right corner) will demonstrate this.
The forward cross tube is conveniently positioned, clear of feet and pedals, but far enough from the aft cross tube to provide a strong and stiff connection of the hulls. The image below shows the geometrical dimensions; a dwg file can also be downloaded.
These are the fundamental and derived measures for the Open Waterbike drive unit geometric interface; the geometry is described in detail in the linked drawing.