Commercial traffic using the lock paid a local toll of 5 cents per gross ton.
All merchant vessels of 500 or more gross tons known or believed to have been lost.
It would turn up the heat on offenders by raising limits of liability to $1,200 per gross ton.
Over seventeen million gross tons of ore went out from 1885 to 1961.
European Union shipbuilders, as a group, were third, producing four million gross tons.
China, a rising competitor, ranked fourth, at 1.6 million gross tons.
The Claymore, built in 1902, 260 tons gross, was an old coastal steamer.
It was built in 1913 at Greenrock and measured 13,405 tons gross.
The Crathie was a steamer of about 475 tons gross and 272 net.
By the end of December 2007, the Society had 6793 ships totaling 152.22 million gross tons under class.