This is funny - U166

[Sailor Steve]

Originally Posted by Lible

A 17-ton boat carrying 20 tons of onions?

Not uncommon at all. Ship tonnage ratings are many and varied. Net tonnage is how much the vessel displaces empty. Gross Rated Tonnage is how much it weighs with fuel, crew, provisions and fittings. Deadweight Tonnage is the ship's cargo capacity, which almost always is more than the GRT.

The most famous example of this is the legendary Great Lakes ship Edmund Fitzgerald. The ship's GRT was 13,632 short tons, or 12,367 long tons, and her DWT was 26,660 short tons, or24,190 long tons. (a short ton is the standard imperial measure of 2000 pounds. A long ton, or ship's ton, is 2240 pounds)

So a boat listed at 17 tons carrying 20 tons of cargo is not unusual.

[edit]I see a newbie beat me to it.

WELCOME ABOARD, tigone!