"Peggie Hall" wrote in message
...
Jeff wrote:
* 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.
Tonnage has nothing to do with the weight or displacement of your
boat.
Glenn Ashmore posted an explanation of tonnage a few years ago...I
saved it...here it is:
Tonnage has nothing to do with the weight of your boat. It is a
measure
of how much wine a vessel can carry.
The word "tun" was originally a size of a cask used to ship wine from
Spain & Portugal to England. In 1347 a tax of 3 shillings per tun
was
imposed and this was called "tonnage." A ship's size became known by
the
number of casks it could carry, and the word tonnage started being
used
to describe a ship's size.
It was found that if you took the length x the breadth x the depth of
the hold under the deck and divided by 100 it was close to the number
of
casks. That is where we get the "Measurement ton" of 100 cubic feet
per
ton.
There are several kinds of tonnage: The first two are used by the tax
collector. The next two are used by designers. The fifth and sixth
are
used by freight salesmen and canal operators and the last one is used
by
the USCG for documenting boats.
Gross Tonnage - is the internal volume in cubic feet of the vessel
minus certain spaces above the main or "tonnage" deck, like stacks and
ventilators, which are called "exemptions" .
Net Registered Tonnage - is obtained by deducting from the gross
tonnage
the volume of space that can't be used for paying cargo or
passengers,
that is to say the space occupied by the engines, the crew's quarter,
the stores, etc.
Displacement Tonnage - is the actual weight of the water "displaced"
by
the ship and is usually quoted in long tons of 2240 lbs.
Light Displacement Tonnage - is the weight with nothing in it.
Loaded Displacement Tonnage - is the fully loaded weight to the
maximum
and is on her summer draft in salt water.
Deadweight Tonnage - is the difference between Light and Loaded
Displacement Tonnage....the actual carrying capacity of the vessel.
Panama & Suez Canal Tonnages - these are different from the
internationally
accepted definitions. There used to be a lot of variations between
countries and the
canal owners thought they were being conned, so they came up with
their own definitions.
Simplified Measurement System - The USCG decided that all this was way
too
much for bureaucrats to deal with for yachts so they came up with
their own formula:
Take the horizontal distance between the outboard ends of the boat not
including rudders and bow sprits. Multiply that by the maximum beam
outside to outside.
Multiply that by the distance from the sheer line not including
bulwarks
or cap rails to the outside bottom of the hull not including the keel.
Add the volume of the deck house/cabin top. Multiply by .5 for
sailboats and .67 for power boats.
Divide by 100.
This will give you the "Gross Tonnage". Net tonnage is 90% of gross
for
sailboats and 80% for power boats.
It should be obvious to anyone who's managed to get this far that your
boat's "tonnage" no longer has anything to do with anything real; it
only exists in the mind of some government bureaucrat.
Another bit of maritime trivia: Rummage was the manner in which the
wine casks were stored in the hold of the ship and came to refer to
the whole ship's cargo. after a voyage any unclaimed and damaged cargo
was stacked on the dock beside the boat and offered for sale - a
rummage sale.
yadayadayadayada. yadayadyaydya. enuf. U think we kair whut girlz say.
whut a stoopid kunt. nobuddy cairz whut U poast. shut yore pi hole.
goway.
todd