... As anyone familiar with
documentation understands, catamarans are actually rated very high by
the formula. My boat, for example, is rated at 22 Gross Tons, even
though her actual displacement is only 4.5 tons.

That's odd. My 42 foot and substantially heavier cat is only 19 GRT
and 15 NRT on my documentation. I wonder how we got such different
numbers. It's really only mattered in Tonga where we paid harbor dues
based on registered tonnage.

-- Tom.