Peggie,

Thanks for that excellent exposition about a subject I used to be very
involved with professionally.

US regulatory tonnage has got to be the weirdest animal beauracrats ever
came up with. Make a boat less safe and less watertight and you can operate
it with a smaller and less experienced crew and less safety equipment.

A 100 Gross Ton vessel, the largest economic size for most passenger
operations due to other regulations, is under 100 feet long if you just
measure an ordinary vessel. Regulatory tonnage lets you play all sorts of
weird games with the structure and deck openings to make the vessel bigger
while measuring the same. I remember designing passenger boats with six
inch high decks because staterooms on decks above the main deck were
measured differently.

I once figured out how to design a 100 Gross Ton vessel 5000 feet long!

--
Roger Long