Ah !! yes the holes.
Thereby lies a design problem. The oar has to move in a radius motion. The round holes have to allow for provision of the oar moving sideways and up and down.
Therefore to maintain a non clunking and jamming of the oar when moved sideways, the centre has to be maintained whilst the outer edges of the hole have to be an angle like a cone. The oar has to be oblong shape to maintain it's vertical position therefore this oblong is presented to the hole and has to move in a rotary movement.
Mechanically, it is actually a bad design, as during it's lifetime, it will wear away the section it rubs. This also creates friction and drag and 30 of them are causing a load on the motor.
Whilst watching them 'do their thing' and drinking loads of coffee, it became more apparent there is more to this than meets they eye. It is also amusing to watch the oars 'drop out' from the side of the craft whilst in motion as there is no form of 'stopper' at the moment.
When there is, then this point will become the rotational pivot point as well, causing extra problems and loading. Hopefully this has been solved with the rotational clamp slotted fixture to allow for the oarsmen to pivot the oar. I just need 60 pins to stop them sliding out.
It all feels as if I'm doing a 'Doctorate' at the university as computers have been ordered to control this system, and we haven't got around to making them go up and down, let alone pausing at each end of the stroke to raise and lower them.
No wonder the slaves were beaten with sticks to keep them rowing.
more later
ken