The confusion is a simple old versus new spelling issue. If we look at a
number of text on who called what what, we'll find some conflicting info.
Your basic statement regarding "cask" is correct regarding weight versus
volume.
BTW, the statement which was still taught in my day for cask was "bung up
and bilge free".

otn

"Ellen MacArthur" wrote in message
reenews.net...

"otnmbrd" wrote
| Gross and net tonnage are volume tonnages and have nothing to do with
| weights.


My teacher told us way back in the old days of wind shipping they had
"tuns". These were like big barrels or casks. If ten could fit inside the
cargo
hold the ship was a ten-tuner. Deck cargo didn't count. Later it got
spelled "ton"
and that's were the confusion comes from. It started out being a volume
thing.
If the tuns were filled with gold they'd be much heavier than filled with
silk
cloth.


Cheers,
Ellen