What is 40 foot long and floats?

Plenty of characters to name - taken around 1980 when the market had not long introduced plastic boxes - aluminium 'kits' can be seen - they held 10 stones (around 65kg) of fish and were used for ling, cod, ray, skate, gurnards and dogs......
although there were notices (and still are) on the market wall about not spitting, it was common practice for the buyers (and anyone else) to walk all over the boxes of fish during a sale.....
up early in the morning after a gale of wind, Fern skipper Alan Goddard looked out of his front room window overlooking Mounts Bay and on the horizon spotted an unusual shape. Reaching for the glasses he recognised the shape to be a floating container - a quick call to son Steve and they soon had the Fern steaming out across the Bay in search of their floating treasure. After securing the 40' container with a line they towed her back to Newlyn and half the village turned out to see what riches lay within - of course, it might have crossed their minds at some time that containers will only float if what lays within is buoyant enough to support all that steel - so when the container doors were finally opened it came as no great surprise to find the treasure was nothing more than several hundred thousand corks - of all shapes and sizes!