The design of the rowlock has probably occupied more time than any other component. A rowlock's simple pupose is to support an oar, and locate it precisely throughout a rowing stroke – but this is easier said than done.

The picture shows the ROCAT's first, simple rowlock. It actually worked very well and, having been all around the houses in the hunt for the production solution, I have returned to something quite similar to this in the end. On this one, a pin in the oar engaged in the wire side loop to limit axial rotation and render the oar captive.

One of the distinguishing features of the ROCAT rigger is that all the rower's effort is transmitted directly to the centreline of the oar through the footbar/rowlock link. This link is in tension, and there are no torsional loads on the swingarm rigger.