Train takes the strain – underwater

Towing a line of oil or gas tanks beneath the waves, instead of building expensive pipelines or filling conventional tankers that lumber over the surface, could deliver substantial cost and energy savings. A ‘Sea Train’ should have minimal water resistance, because of its small frontal cross section. And although it would have to be strong enough to withstand depth pressure, it should not need any of the robustness required by surface vessels to resist storm conditions. It could fill up sub-sea, doing away with much of the cost of oil platforms and should be relatively immune to threats of either war or terrorism. The idea of towing a series of containers sub-sea is the brainchild of Ian Holmes, a joiner based in Ore, near Hastings, who originally conceived of the idea to transport passengers at lower cost and in greater comfort than is possible in either airliners or ferries. The notion of using submarines to dock with undersea oil wells and carry crude oil was originally put forward by now-retired UK naval architect Charles Gonzalves in the 1970s. But it seems nobody has patented – or even considered – the idea of having a whole series of submarine oil tanks or containers for goods or people strung together like a train. This has enabled Holmes to obtain a US patent. While the basic idea is simple enough, getting it to work would mean applying technologies that were not generally available until recently. “There may be changes of water density or temperature which can be quite localised and which cause following submarines to move up or down, or the water may become shallow,” Holmes accepts. “Also, there may be occasions where the submarine needs to dive deeper under some kind of floating obstruction. As the lead submarine dives below the obstruction, it is essential for the following submarines to follow the same path.” Similarly, if the train is to get safely in and out of harbour, it is necessary to make the following tanks or containers move along the same path as the lead submarine. This means that each element of the train must have its own navigation system and at least some means of steering itself with individual fins and hydroplanes, if not thrusters as well. And if the whole train is not to multi-jacknife when it stops, there will have to be some form of braking mechanism on each element. The developers suggest nuclear power as a propulsion mechanism, though Canadian engineers have pioneered submarine propulsion systems that use fuel cells made by Ballard Power to provide sufficient endurance to go under the Arctic ice. Design speed is 60-70 knots, assisted by rubber fairings over the joints between elements to reduce drag. Optimum running depth would be about 150 feet (50m) – deep enough to be below wave action, yet not so low as to require massive engineering to resist depth pressure. The development is still at the concept stage, although there has already been keen commercial interest. Ideas mooted include toys and a kind of underwater train that could run in a pipe. Pointers * Concept consists of having a front submarine towing a series of submarine tanks or containers * System could transport, oil, gas, cargo or passengers * Advantages would include low water resistance, owing to small frontal cross section, avoidance of surface waves and storms, and improved security * It would be necessary for each towed element to have at least steering fins, hydroplanes and water brakes, plus a navigation system to ensure that it followed the same path as the towing submarine, both laterally and vertically