- further to Peter Bick's useful information in the Winter issue, here is a little more, primarily related to inland oars

I have several rowing boats on Coniston Water, and my interest was originally caught when I made a clinker built dinghy, and found the information on oars in the books quite inadequate. I measured and weighed as many oars as I could get my hands on, thus accidentally collecting a quantity of information. I knew Eric McKee quite well, because my inland knowledge complemented his seagoing knowledge, and I helped him in his work on the reconstruction of the Greek Trireme.

As I see it the situation for an inland, non-racing, boat with fixed seats is as follows. The width between rowlocks depends on the size of the human body, and about 5'1" to 5'3" seems the best. This is more than the beam of many small boats, hence the use of short steel outriggers. Oar handles don't normally overlap, about 1" gap is allowed so you don't smash your thumbs, should you put them over the end of the oar.

The ratio between the inboard length and the outboard length is the 'gearing'. You can either measure to the end of the oar, or to its centre of pressure, and the centre of the handle. It makes little difference but you should be consistent. A gearing of 1:2 is very low, and 1:3 is very high, usually you are around 1:1.5 to 1:1.75 or so. Fast boats have high gearing, but boats that need fierce acceleration need low gearing, so racing boats are geared relatively low.

The area of the oar blade is about one square foot, related to the strength of the oarsman. The shaft usually finishes to just over 2" diameter, again related to strength. The wood should be a softwood, i.e. faultless Sitka, as this is less flexible than a hardwood shaft of the same strength. Flexibility feels uncomfortable but the energy used in bending the shaft is not lost.

At rest the oar blade should be covered by the water. This needs the centre of gravity to be so placed that the oar blade will drop if released. And it means that a downwards force needs to be applied to the handle to raise the blade from the water. This force on the handle should be about 4 lbs for a normal single-handed oar (i.e. scull) and double that for a two-handed oar. 2 lbs is better for a child. 8 lbs is almost too heavy to use at all.

This fixed handle pressure combined with the inboard length of the oar will give you a position for the centre of gravity, and a maximum length and weight for the outboard part of the oar. To get a gearing as high as 1:3 you have to have extremely fine construction for the blade. So for a more knock-about oar, a lower gearing is likely to be necessary. (If you have a boat with very high freeboard and have to have unusually high gearing the handle pressure may be too high and the loom of the oar then has to be weighted with a slab of lead or something. Not desirable but it makes it workable.)

If you want to measure an existing, oar you can suspend it by a spring balance from its centre of gravity. This gives the total weight as well as the position of the CG. And you take the overall length and the rowlock position. You can then calculate the handle pressure.

I must emphasise that you start with the 4 lb handle pressure and the width between the rowlocks. Everything else follows as the night follows day. Needless to say you have to take into account things like the weather in your district, i.e. height of waves, the boat's freeboard etc., and the weight and shape of the boat. But given this ideal design, you can try and find, or alter, an oar to suit. The closer you can get to the ideal the better it will work, the easier the boat will be to row, and the faster it will go.