Tandem Tow

On April 13th of this year I wrote about catenary of the tow wire. When towing on the ocean you pay out a lot of tow wire to create a non-linear spring function. It means nothing more than that you prefer to have some weight in the water. Should shock load occur, your wire will not break immediately but comes up first. Another aspect you can use from catenary is that you are able to tow a double or tandem tow. The wire of the second barge has much more weight in the water than the first one, while the change in dynamic forces on both wires is the same. They will come up and down simultaneously. If you have enough wire out, the wire of the second tow will have its catenary right under the first barge, without touching it. The word catenary comes from the Latin word 'catena' which means chain. Galileo claimed that the curve of a chain hanging under gravity would be a parabola, but this was disproved by Euler in 1669. How could he know without any Ocean going tugs invented? Here you see the Husky shortening up her tandem tow in order to hand the first barge over to us.