The Weight

Here you see a part of the approximate 22.000 tons of the empty Western Albertito resting on (and almost crushing) the dockblocks.
Weight in shipping comes in quite some different versions, first of all deadweight which means the weight a ship can carry when loaded to her plimsoll marks. You'll see the DWAT and DWCC version sometimes. AT stands for All Told where CC means Cargo Capacity. All Told is thus the same as the original Deadweight version (DW)
Next is Deplacement, it is the weight of the volume of seawater displaced by the vessel. According to Archimedes you'll have to multiply the volume in m3 by the (metric) density of the displaced water to get her weight. This is the weight of the complete vessel together with cargo, fuel, crew and all.
Finally the old one like Gross Register Tons. It is a volume and goes all the way back to the 13th century when the British imported wine from France in big barrels called "Tuns". That's where the word ton comes from.

At last a complete different version; I am a big fan of the music of The Band. They wrote a song called The Weight, and since I heard this song for the first time in 1977, I have absolutely no clue what they try to tell me with these lyrics. Probably it is all drugs related.
Apparently I am not the only one, it is still a mystery. Check this LINK for yourself. If you know what's it about, I like to hear from you.