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Jeff

* wrote, On 4/9/2007 11:20 PM:
... 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.

The measurement is greatly affected by certain design features. For
example, faired in keels are part of the depth, fins or daggerboards
are not. The deck house or trunk may or may not be included,
depending on whether its considered "flush deck" for the rule. But
the big difference would be whether you got measured as a catamaran,
or as a monohull under the simplified rule.