Tonnage

My understanding on this refers to port and canal charges.
Am I right in saying that net tonnage is used in some instances when using canals, and in port a different charge based on gross tonnage.
Port fees vary between ports in the same country at times and can greatly vary between countries.

There are all sorts of different charges John, the Suez Canal had its own tonnage certificate for the fees for transiting the Canal , which as said years ago when some were complaining about having to clear out the focsle head space , this was assumed to be a void space on the Suez Canal certificate and could have invoked extra charges as could be considered cargo. So think of it as earning a few extra Bob for the shipowner. JS

John
I remember the bosun on my first ship explaining why we had to empty the forecastle on my first trip through the Suez, all the ropes, and rag bags etc.
Boy, this site is realy preventing me from getting Altimeters.
Des

Altimeters/Alzheimers not much different Des. As long as it’s not depth sounders / canvas shrouds. JS