 The May 1799 test, above, occurred when a party of investors was aboard the vessel and they nearly suffocated before they could be freed.Work on the second lock was suspended (the third lock had not been started) and early in the following year an inclined plane, to carry boats’ cargoes in wheeled tubs, was built instead.Eventually a flight of nineteen locks on a longer alignment up the slope was constructed, with a Boulton & Watt Steam Pumping Station, capable of lifting 5,000 tons of water in 12 hours, used to recirculate the water.