Question about a number

[Windy]

Hello All;
Brand new around here
I'd like to ask a question about a number on a plaque attached to the mainbeam in the old Vivacity 24 sailboat I recently purchased here in Canada........

The number goes like this.... (this is not the actual #)

ON123456
Reg tons 3
48/100

Is this a British Registration number and if so where could i obtain more information pertaining to it?

Thanks;
Dave

 

[VicS]

Yes thats the official number and the registered tonnage. Do not know if that is British or not, originally there would have been the port of registration on the transom along with the boats name.

The starting point for enquiries would now be here

 

[FullCircle]

The 3 and 48/100 tons is made up of how many barrels of a particular volume could be fitted I think. Called Thames tonnage?

 

[Windy]

Hello Vic S and thank you for the link....
The orginal name and port have been removed from the transom, the man from whom i purchased the boat, said, he allowed the original keeper to retain the "log book" and related documents.......

He told me the vessels maiden voyage was a circumnavigation of the British Isles........

Here in Canada we have the option of registering a vessel or licenceing the vessel (less complicated)

This boat is licensed in Canada

I enquire because i would like to piece together a history of the boat........

I will follow up on the link provided..........

 

[Windy]

Hello Full Circle and thank you for that info..........
I believe thats what they call it in Canada also.
Being once a colony, many of our forms are taken straight from British sources, particularly ship registration.....
Hey ! "if it ain't broke don't fix it" is our motto /forums/images/graemlins/grin.gif

 

[VicS]

"Thames tonnage" is was originally based on the number of "tun" barrels of wine (252gallons) that could be carried. It is calculated from length and beam according to the formula {(L-B) x B x 1/2B}/94. Dimensions in feet presumably. It is applied to pleasure craft and is also sometimes known as the "Yacht tonnage" but is not to be confused with the Ton rating for racing yachts which is derived from a French tonnage rule of 1892.

The "Registered tonnage" is basically the internal capacity of a vessel, a registered ton being 100 cubic feet. The capacity of other spaces above the "tonnage deck" can be added to give the "Gross tonnage".

The capacity of "non-earning" spaces eg spaces occupied by engines, tanks, stores, crews quarters, navigation space etc can be deducted (if already included in the gross tonnage) to give the "Nett tonnage".

"Displacement tonnage" is the weight of the vessel and is, obviously, equal to the weight of water displaced. The meanings of "Light displacement" and "Loaded displacement" refer to the weight of the vessel and her equipment and to the weight loaded with water, fuel, cargo, stores and passengers respectively. The difference between these two is the "Deadweight tonnage"

I am sure the 3 48/100 figure is the registered tonnage. The words Reg tons rather confirms that IMO, but it may be the Gross registered tonnage (grt)

 

[peterb]

[ QUOTE ]
"Thames tonnage" is was originally based on the number of "tun" barrels of wine (252gallons) that could be carried. It is calculated from length and beam according to the formula {(L-B) x B x 1/2B}/94.

[/ QUOTE ]

Not so. The formula given here was only introduced in the 1850s by the Royal Thames Yacht Club to produce a fairer method of yacht handicapping.

"Tonnage" was first introduced by Edward I in 1303, and controlled both the hire charges and the harbour dues on a cargo vessel. Although it was based on the wine-carrying capacity of a ship, a second tax, known as tunnage, was introduced by Edward III in 1347. Tonnage related to the nominal capacity of the vessel, whilst tunnage was based on the actual amount of wine imported. At three shillings (15p) per tun there was something to be said for the 'grand old days'. (A tun was about 105 gallons, 477 litres.)

Tonnage was originally calculated from length x beam x depth of hold divided by 100. When for legal purposes it became necessary to have a more accurate measurement (in 1694) the same L x B x D formula was used, but divided by 94.

This stayed until 1773, when a formula known as "Builders Old Measurement" (BOM) was introduced. This used [(L - 3/5 B) x B x 1/2 B] / 94, and remained in force until the introduction of iron ships with their much greater length/beam ratios. A new rule called "Moresom's Rule" was then introduced, which made a more accurate calculation of the volume of the ship's hull below the upper deck. At 100 cubic feet to the ton, this became the ship's gross tonnage. A second calculation was made of the 'wasted' capacity (crews quarters, engines, stores, etc.); this was subtracted from the gross tonnage to give net tonnage. Both gross and net tonnages are registered tonnages, since both appear on the ship's registry certificate. In the case of a yacht, all the space is 'wasted', with no usable cargo space, so only the gross tonnage is significant, and that is the one which should be marked on the vessel, together with its 'official number' (ON).

All from "The Oxford Companion to Ships and the Sea".

 

[VicS]

Not entirely wrong then, except for the size of a "tun". Was based on wine carrying capacity but now calculated from the formula for a diffrent purpose.

That's another book to get for the bookshelf!

 

[peterb]

Highly recommended. It's one of those books that you pick up to look for one thing, then put down two hours later having looked at a dozen other things. Looking for tonnage had me looking at ASD tugs, fighting tops, trawls, fish and fisheries, flag etiquette (did you knoe that it is called yacht routine in the USA?) and the history of yachting. One of the best time-wasters I know!