ship-measure-msg – 11/6/05
Measuring period ship sizes. tonnage, tun, cargoes.
NOTE: See also the files: ships-msg, ships-bib, med-ships-art, boat-building-msg, nav-inst-msg, Seakeeping-p1-art, rope-msg, hemp-msg, stockfish-msg.
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This file is a collection of various messages having a common theme that I have collected from my reading of the various computer networks. Some messages date back to 1989, some may be as recent as yesterday.
This file is part of a collection of files called Stefan's Florilegium. These files are available on the Internet at: http://www.florilegium.org
I have done a limited amount of editing. Messages having to do with separate topics were sometimes split into different files and sometimes extraneous information was removed. For instance, the message IDs were removed to save space and remove clutter.
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Thank you,
Mark S. Harris AKA: THLord Stefan li Rous
Stefan at florilegium.org
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Subject: Re: [Sca-cooks] OT-knots and medieval boats
To: sca-cooks at ansteorra.org
From: Jeff.Gedney at Dictaphone.com
Date: Mon, 30 Dec 2002 11:43:49 -0500
Stefan asked:
> > Patron of the East Kingdom Nautical Guild of St Erasmus
> > Master of ye Wycked Bitche, a 49 tonne lugger, plying the coaster trade
> > out of Yarmouth in East Anglia.
>
> Okay, landlubber question. Exactly what is the "49 tonne" referring to
> here? Weight of the vessel? Displacement? Maybe those two are the same?
> Or the wieght of the cargo it can carry? What does that work out to
> in size measurments? (other than rather small, although you did say
> "coaster").
OK, here goes:
In period, as a general rule, ships were rated by the amount of cargo they
could carry, this was not measured in weight, but in the number of tun
barrels of liquid she could carry. The Tun was generally 252 gallons,
usually, though the Spanish tun varied rather a lot, and could be as little
as 125 gallons- which made any Spanish estimate of the size of ships rather
suspect.
This should not be confused with the modern measurement of Tons, which is
actually the weight of water she would displace, when full. As any student
of Archimedes will tell you, this also happens to correspond to the total
weight of the ship, crew cargo and supplies.
This was one common period measure of ships capacity, another is the number
of "Chaldrons" of Coal, Bales of cloth, or bushels of grain she could
carry. All were used rather interchangeably, and all referred to the only
measurement that really mattered to a merchant seaman, how much bulk cargo
could she carry.
"Tonnage" was actually an estimate - based not on actual usage, but on the
ships dimensions, according to a formula recorded by Master Matthew Baker,
a famous ( perhaps the most famous ) Elizabethan shipwright.
The formula used by Baker is recorded as : (LOA x W x D)/100 ( - length
overall (in feet) x maximum width (in feet) x total depth of hull(feet)
divided by 100 )
Because it required nothing more than the gross overall dimensions,
measurement in Tonnes became the generally accepted standard, and the other
measurements are infrequently used, except the Chaldron. That measurement
was generally limited to the traffic moving through NewCastle on Tyne or
the port of Tynesmouth, where "NewCastle coal" or "sea coal" (because it
originally was gathered up as it washed ashore after a storm) was mined and
shipped all over England, and to France. Coal was a staple of the
"coasting" Trade, along with Salt, Salted Herring, "raw" cloth, and Grain.
"Coasting" is basically short range shipping practiced along the coasts and
waterways of England. [The above info is from: Williams, N.J., Maritime Trade of the East Anglian ports; 1550–1590, New York: Oxford University Press 1988. Info given to Stefan by Capt Elias on 11/05]
Since Tonnage was based on an estimate, it was not a firm measure.
Depending on how she is packed, the size of the hold as constructed, and
what other gear she carries, a ship of 49 tonnes may be able to carry
anywhere from 30 to 52 tonnes worth of cargo.
49 tonnes in 1594 (the period of the Bitche) is a mid sized craft, though
100 years earlier she would have been considered quite large. She works out
to about 35 feet long, 14 feet wide, and 10 feet deep, - 4 foot below water
(or "draft"), 6 foot above the waterline (or "freeboard"), though fully
loaded those may values reverse. Pretty "beamy" (wide compared to length) -
like most merchant ships of the day, rather a lot like a bath tub.
OBFood content (to Make Papa Gunthar happy):
The primary cargoes carried by coasters of the East Anglian region are
Grain and Salted herring, with salt, coal, wine and cloth stuffs. the salt
and wine were generally carried from France, and were generally traded for
in exchange for Salt Herring, and grain. The French appetite for salt
herring was the foundation of many a Tudor era fortune.
Personally I can't understand why. The stuff makes me gag.
Brandu/Elias
Sources:
Friel, Ian, "The Good Ship: Ships, Shipbuilding and Technology in England,
1200-1520", British Museum Press, London, 1995
Gjessing, Gutorm, "The Viking Ship Finds", J. Petlitz Boktrykkeri Oslo,
Norway, 1955
Tryckare, Tre., "The Lore of Ships", Crescent Books, 1972
Williams, N. J. The Maritime Trade of the East Anglian Ports, 1550-1590.
Oxford: Clarendon Press, 1988.
From: "Decker, Terry D." <TerryD at Health.State.OK.US>
To: "'sca-cooks at ansteorra.org'" <sca-cooks at ansteorra.org>
Subject: Re: [Sca-cooks] OT-knots and medieval boats
Date: Mon, 30 Dec 2002 14:29:03 -0600
A very nice exposition, Brandu. Please allow me to add a few comments.
> > Okay, landlubber question. Exactly what is the "49 tonne" referring to
> > here? Weight of the vessel? Displacement? Maybe those two are the same?
> > Or the wieght of the cargo it can carry? What does that work out to
> > in size measurments? (other than rather small, although you did say
> > "coaster").
>
> OK, here goes:
> In period, as a general rule, ships were rated by the amount of cargo they
> could carry, this was not measured in weight, but in the number of tun
> barrels of liquid she could carry. The Tun was generally 252 gallons,
> usually, though the Spanish tun varied rather a lot, and could be as little
> as 125 gallons- which made any Spanish estimate of the size of ships rather
> suspect.
"Tun barrel" is redundant. By definition, a "tun" is a barrel to hold
liquids and appears in Old English as "tonne." There are related words in
the various languages over the Celtic range, so it is believed the origin
may be Celtic (defined in this context as a group of related cultures and
languages spread from Asia Minor to Ireland).
The tun of 252 U.S. gallons (the same as the Elizabethean wine gallon) is an
English measure of approximately 2 butts or 4 hogsheads or 8 barrels
(Elizabethean wine measure).
The Danish "tonde" is about 139 liters, which makes it roughly equivalent to
the English wine barrel (119.24 liters). It is related to one of the
meanings of the German "Tonne" meaning "barrel" (a usage for which I have
been unable to determine any specific measure).
The "tonelada" is a traditional Spanish and Portuguese weight measure
standardized from their "tuns." The Spanish "tonelada" is 2000 Spanish
"libras" (about 919.9 kg). The Portuguese "tonelada" is 1728 Portuguese
"libras" or "arratels" (about 793.15 kg). Variations between Spanish,
Portuguese, Genoese (there were several colonies in Spain and engaged in
trade) and Moorish measures may be part of the problem with the wide
variation in Spanish measures of the period. A number of Spanish measures
(especially land measures) were standardized in 1568, but the old measures
continued to be used.
> This should not be confused with the modern measurement of Tons, which is
> actually the weight of water she would displace, when full. As any student
> of Archimedes will tell you, this also happens to correspond to the total
> weight of the ship, crew cargo and supplies.
Tons displacement is commonly used to measure warships, although it is
sometimes on other craft ("register tons" are more common for merchant ships
covered a little later). A ton of sea water is about 35 cubic feet, so
every 35 cubic feet of water a ship displaces is a ton displacement.
Although there is no real correspondence, the English "tun" is about 33.7
cubic feet.
> This was one common period measure of ships capacity, another is the number
> of "Chaldrons" of Coal, Bales of cloth, or bushels of grain she could
> carry. All were used rather interchangeably, and all referred to the only
> measurement that really mattered to a merchant seaman, how much bulk cargo
> could she carry.
"Chaldrons" (AKA chalder or cauldron) are worth a look. Deriving from the
French for "large kettle," it is an English measure for dry commodities
(coal, lime, etc.) standardized at 36 bushels. More modernly, as a measure
for coal, a chaldron is 1/8 keel (a keel being 21.5 metric tons and
approximately the cargo capacity of a Tyne river barge in 1695).
Bales of different goods produce different measures. A bale of paper is ten
reams. A bale of cotton is 500 US pounds or (Egyptian cotton bale) 720
British pounds (down from an original 750 pounds).
> "Tonnage" was actually an estimate - based not on actual usage, but on the
> ships dimensions, according to a formula recorded by Master Matthew Baker,
> a famous ( perhaps the most famous ) Elizabethan shipwright.
> The formula used by Baker is recorded as : (LOA x W x D)/100 ( - length
> overall (in feet) x maximum width (in feet) x total depth of hull(feet)
> divided by 100 )
>
> Because it required nothing more than the gross overall dimensions,
> measurement in Tonnes became the generally accepted standard, and the other
> measurements are infrequently used, except the Chaldron.
>
> Brandu/Elias
These are usually referred to as "register tons" because this is the method
used to gauge ship capacities in most ship registries. A register (or
merchant marine) ton is 100 cubic feet.
If you come across any information on standardization of any of these
measurements, please let me know. I'm trying to chase down some of the
history to clarify precisely when some of these changes occurred.
Bear
<the end>