Making a forward splash
John Stevenson explains the thinking behind his ‘double-knuckle rowing linkage’
The idea of rowing a boat is as old as time: however, the basic technique of rowing has not changed. I had one of my daft ideas recently, based on the notion that if you could comfortably (and efficiently) row a boat facing forwards, why would you want to face backwards?
Therefore, I armed myself with several lengths of scrap timber – formerly the framework of my sons’ redundant built-in wardrobes – and a selection of roofing bolts, at minimal cost. My brother already had a suitable dinghy to modify, in the name of science. Fortunately, it was already fitted with two positions for rowlocks, so we used the existing rowlock mounts and set to work constructing our rowing linkage.
The idea initially worked, but it was obvious that the dummy oars needed to be brought further inboard, so we drilled two more holes. On the second attempt a connector bolt sheared under the severe leverage loading, so we drilled two more holes and changed the 6mm bolts for 8mm bolts – and on the third sea trial, it all worked a treat.
I guesstimate that by rowing conventionally, I could row at a speed of about 2.5 knots: with the forwards rowing arrangement I could probably row at about 1-1.5 knots, but if the arrangement was properly engineered the difference between the two would diminish considerably. The original rowlock positions on the dinghy we used were not in an ideal position, and the seat was a fender, but this was all good enough for trialling purposes.
Hire boats on rivers and park lakes often seem to be occupied by folk who are not entirely sure which end is ‘the front’ – and in a way, they pioneered the concept of the ‘double-knuckle rowing linkage’. A conventional oar has a single fulcrum point, known as a thole pin, which is a simple vertical pin around which drops a metal loop attached to the oar – or, alternatively, a ‘crutch’ which is a U-shaped oar support. The use of this inevitably means that a pull forwards on the oar handle results in a force applied backwards on the oar and its blade. To harness the best position and utilise the rower’s strength, it is necessary for the rower to sit facing the stern of the boat. Consequently, a single rower has very poor forward vision.
The concept of the doubleknuckle oar provides a very simple solution. For each oar, there are two fulcrum points: one supports a ‘dummy’ oar, which projects into the boat only, and in addition to the dummy there is also a conventional oar positioned either ahead or astern of the dummy, projecting outboard only. The oar and dummy are linked by a swivelling connector running from inside the boat to outside it: this ensures that a stroke of the dummy oar is mimicked by the oar itself.
Full forward vision
Consequently, a rower facing forwards can exert his full strength backwards, pulling the oar itself backwards and propelling the boat forwards. This would enable the rower to benefit from full forward vision – ideal for, say, someone who wanted to quietly creep along a shoreline looking for otters, herons or other wildlife. To achieve maximum advantage, the outboard swivelling point could be adjustable, effectively giving an ‘easy’ or ‘fast’ rowing option. As in conventional rowing, a footrest would be required.