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IDUNA's Official Canadian Register states 7.73 net tons. I do not know if this is a calculated number or actual tonnage. IDUNA's interior is solid teak and Alaskan yellow cedar. Our engine weighs 443 lb. (200 kg). We believe IDUNA's gross tonnage is higher than that of a Sam L. Morris Co. built boat.
Sorry I can not be of more help.
Rod
S/V IDUNA
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— In bcc@yahoogroups.com , “Rod Bruckdorfer” <seagypsy@a…> wrote:
IDUNA’s Official Canadian Register states 7.73 net tons. I do not
know if this is a calculated number or actual tonnage. IDUNA’s
interior is solid teak and Alaskan yellow cedar. Our engine weighs
443 lb. (200 kg). We believe IDUNA’s gross tonnage is higher than
that of a Sam L. Morris Co. built boat.Sorry I can not be of more help.
Rod
S/V IDUNA
Tonnage is a volume measurement (100 cu ft) rather than a weight.
Gross is all space belowdecks, net subracts the machinery spaces and
tanks. All BCC’s should have the same actual tonnage, but in reality
it is calculated using formulae. I think the term deadweight tons
may be a displacement measurement. If you get USCG documentation,
you send them the dimensions (LOA, beam, hull depth), they calculate
the tonnage. I think my document shows 6 net tons. Have to be at
least 5 net tons to be documented. Do not think USCG does decimals,
but other countries do and may use different formulae for the
calculations. The Brits refer to yachts by their tons of
displacement. These are long tons, so the BCC is about 6 1/2 tons.
John Churchill
My BCC #064 (built by the Sam L. Morse Company) was surveyed at 6.58 net
tons when I registered it in Canada.
-----Original Message-----
From: jcskua <jchurchill@erols.com > [mailto:jchurchill@erols.com ]
Sent: Friday, January 10, 2003 2:21 PM
To: bcc@yahoogroups.com
Subject: [bcc] Re: Gross Tonnage
— In bcc@yahoogroups.com , “Rod Bruckdorfer” <seagypsy@a…> wrote:
IDUNA’s Official Canadian Register states 7.73 net tons. I do not
know if this is a calculated number or actual tonnage. IDUNA’s
interior is solid teak and Alaskan yellow cedar. Our engine weighs
443 lb. (200 kg). We believe IDUNA’s gross tonnage is higher than
that of a Sam L. Morris Co. built boat.Sorry I can not be of more help.
Rod
S/V IDUNA
Tonnage is a volume measurement (100 cu ft) rather than a weight.
Gross is all space belowdecks, net subracts the machinery spaces and
tanks. All BCC’s should have the same actual tonnage, but in reality
it is calculated using formulae. I think the term deadweight tons
may be a displacement measurement. If you get USCG documentation,
you send them the dimensions (LOA, beam, hull depth), they calculate
the tonnage. I think my document shows 6 net tons. Have to be at
least 5 net tons to be documented. Do not think USCG does decimals,
but other countries do and may use different formulae for the
calculations. The Brits refer to yachts by their tons of
displacement. These are long tons, so the BCC is about 6 1/2 tons.
John Churchill
BRISTOL CHANNEL CUTTER OWNERS ASSOCIATION
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I believe John is entirely correct. For more info on tonnage, here are some terms
from the glossary of a book “Naval Architecture for Non-Naval Architects” by
Prof. Emeritus Harry Benford and published by the Society of Naval Architects
and Marine Engineers (SNAME), copyright 1991, ISBN 0-030773-08-2
Ton: A unit of weight, usually a long ton of 2240 pounds, or a metric ton of about
2205 pounds.
Tonne: A metric ton. [which is 1000 kilograms]
Tonnage, gross: An approximate measure of a vessel’s total volume. Under vessel
measurement rules of various nations, the Panama Canal and the Suez
Canal, a measure of the internal volume of spaces within a vessel in which
1 ton is equivalent to 2.83 cubic meters or 100 cu ft. Under the International
Convention of Tonnage Measurement of Ships (ICTM) 1969, a standardized
numerical value that is a logarithmic function of spaces wihin a vessel. Gross
tonnage according to ICTM is GT=K1 x V [the 1 is supposed to be a subscript
but I don’t know how to make a subscript] in which V is the total molded volume
of all enclosed spaces of the ship in cubic meters [molded is a term that refers to
the surface defined by the inside of the hull shell rather than the outside] and K1 is
0.2 + 0.02 log10V [log10V is the log base 10 of V, enough to cause a headache].
Tonnage, net: An approximation to a vessel’s money-earning volume. Net tonnage according to
canal rules is derived from gross tonnage by deducting an allowance for the propelling
machinery space and certain other spaces. Net tonnage according to ICTM is a
logarithmic function of the volume of cargo space, the draft-to-depth ratio, the number
of passengers to be accommodated, and the gross tonnage.
Deadweight: The carrying capacity of a ship at any draft and water density. Includes weight of
cargo, dunnage, fuel, lubricating oil, fresh water in tanks, stores, passengers and baggage,
crew and their effects.
And, for some considerably more interesting reading, here’s this:
http://old.sailingworld.com/forums/arch_067/index.pl?read=283087
You can bet that the Coast Guard has greatly simplified their calculations for yacht tonnage in the
interest of expediting their work, no need to sweat bullets at the thought of having to recall how
to do logarithms.
However, if you are a glutton for punishment (or else are having trouble getting
to sleep) then you can always read the Code of Federal Regulations:
http://www.access.gpo.gov/nara/cfr/waisidx_98/46cfr69_98.html
Enjoy,
Tod