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Author Topic: displacement of HMY Britannia (1893)  (Read 3345 times)

vwlucas

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displacement of HMY Britannia (1893)
« on: September 10, 2007, 06:33:24 PM »

Hello everybody,

My name is Jacques; i make model ships for about 30 years. I made static models, then RC models, and then a model yacht (32") last year.

I would like to built the model of HMY Britannia (1893), on scale 1/30, with the plan (full of fantasy  ::)) from Nantua.
The problem is I can't find serious information concerning the ship, except

Displacement: 221 tons
Length: 121 ft
Beam: 23 ft 4 in
Height: 164 ft
from the site of Wikipedia.

I need the displacement of the real ship for calculating this of tne model.
Can somebody help me?
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DickyD

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Re: displacement of HMY Britannia (1893)
« Reply #1 on: September 10, 2007, 06:40:57 PM »

Excuse me for pointing this out Jacques but you asked for the displacement of the real ship and you have just given it to us as 221 tons. :-\
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vwlucas

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Re: displacement of HMY Britannia (1893)
« Reply #2 on: September 10, 2007, 07:00:20 PM »

Well DickyD, I doubd over my own information.
Certainly if I compare with the displacement of other yachts from this period:

Vigilant: lenght 106 ft, disp 96 tons
Columbia: lenght 120 ft, disp 102 tons.
Britannia, lenght 121 ft, disp 221 tons? She was not a merchant ship, was she?  ;D

Therefore my question
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DickyD

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Re: displacement of HMY Britannia (1893)
« Reply #3 on: September 10, 2007, 07:25:46 PM »

This might help.
The Clyde was not only famous for producing the greatest and largest vessels afloat, it was also one of the top yacht-building centres.
One of the most famous yachts ever built on the river was HMY Britannia.
She was the creation of yacht designers G.L.Watson, still producing world-class vessels, and she was built at Henderson's yard in Partick.
The cutter was commissioned for The Prince of Wales, later Edward VII, who had a passion for sailing.
She was launched in 1893 and was the last of the great royal sailing yachts.
Britannia weighed more than 200 tonnes and was just under 125ft long.For most of her 40-year career, Britannia was the world's fastest yacht and managed to win more than half the number of competitions she entered.
When Edward VII died in 1910, the yacht was passed on to his son, George V - who was also a keen yachtsman - and Britannia continued her illustrious career.
However, the King's sons did not share his passion for sailing, so he willed that on his death the yacht should be scuttled.
He died in January 1936 and after her gear had been sold she made her final voyage in the summer to the southern tip of the Isle of Wight.
Explosives were fired into her hull and the famous world-class yacht sank.

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vwlucas

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Re: displacement of HMY Britannia (1893)
« Reply #4 on: September 10, 2007, 07:47:03 PM »

Well, Thanks, Richard, this is a good news! O0

The model will be
lenght (hull) 1.16 m
Beam 22.5 cm
Height 1.66 m
Displacement 8.6 Kg.

The scale 1/30 is than suitable!
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gingyer

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Re: displacement of HMY Britannia (1893)
« Reply #5 on: September 10, 2007, 08:11:38 PM »

Hi there
I found this info about the yacht
it is from the recoeds from ships built on the clyde

HMY BRITANNIA
--------------------------------------------------------------------------------
built by D & W Henderson Ltd Glasgow,
Yard No 366

--------------------------------------------------------------------------------
Propulsion: sail
Launched: Thursday, 20 April 1893
Built: 1893
Ship Type: Yacht
Tonnage: 221 grt
Length: 124 feet
Breadth: 23 feet
Owner History:
HRH Prince of Wales
Status: Sunk - 1936

Remarks: Scuttled off St Catherine's Point on the orders of King George V, who inherited it from King Edward VII, he wanted her scuttled after his death. Designed by Glasgow firm GL Watson, the first yacht design studio to be established in the world and still very much in existence today, she was the fastest yacht in the world and won 350 first
prizes in 635 races.

hope this helps

Colin
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malcolmfrary

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Re: displacement of HMY Britannia (1893)
« Reply #6 on: September 10, 2007, 09:10:17 PM »

One of the most important and famous victories of her career was winning the America's Cup the year after her launch.
I would query that bit.  The only winners of the Americas cup until the Australians got it in the 1980s were American yachts.  Perhaps she won the right to challenge?
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vwlucas

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Re: displacement of HMY Britannia (1893)
« Reply #7 on: September 10, 2007, 09:24:20 PM »

Hello,

 ??? Britannia trained with Shamrock (chalenger for the America's cup) in 1899. And she  has never taken part in this competition.
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vwlucas

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Re: displacement of HMY Britannia (1893)
« Reply #8 on: September 11, 2007, 07:44:44 AM »

http://Propulsion: sail
Launched: Thursday, 20 April 1893
Built: 1893
Ship Type: Yacht
Tonnage: 221 grt


Well, well, can somebody translate from Gross tonnage to Metric tons?

I'm a stupid continental (a "barbaros" :D), living in a country applying the metric system since 1806... ;)

Jacques
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Bunkerbarge

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Re: displacement of HMY Britannia (1893)
« Reply #9 on: September 11, 2007, 08:15:13 AM »

I think there is more confusion over the definitions of weight and displacement than in any other area of Naval Architecture.  Gross Registered Tonnage is actually a measurement of volume not weight and so should be refered to in a volumetric unit such as M3.

The definitions below might help to clarify the issue.


Gross Register Tonnage (GRT) represents the total internal volume of a vessel, with some exemptions for non-productive spaces such as crew quarters; 1 gross register ton is equal to a volume of 100 cubic feet (2.83 m). This calculation is complex; a hold can, for instance, be assessed for grain (accounting for all the air space in the hold) or for bales (exempting the spaces between structural frames). Gross register tonnage was replaced by gross tonnage in 1994 under the Tonnage Measurement convention of 1969, but is still a widely used term in the industry.

Net Register Tonnage (NRT) is the volume of cargo the vessel can carry; ie. the Gross Register Tonnage less the volume of spaces that will not hold cargo (e.g. engine compartment, helm station, crew spaces, etc., again with differences depending on which port or country is doing the calculations). It represents the volume of the ship available for transporting freight or passengers. It was replaced by net tonnage in 1994, under the Tonnage Measurement convention of 1969.

Gross Tonnage (GT) refers to the volume of all ship's enclosed spaces (from keel to funnel) measured to the outside of the hull framing. It is always larger than gross register tonnage, though by how much depends on the vessel design. . It was a measurement of the enclosed spaces within a ship expressed in "tons" a unit which was actually equivalent to 100 cubic feet.

Tonnage measurements are now governed by an IMO Convention (International Convention on Tonnage Measurement of Ships, 1969 (London-Rules)), which applies to all ships built after July 1982. In accordance with the Convention, the correct term to use now is GT, which is a function of the moulded volume of all enclosed spaces of the ship.




While not "tonnage" in the proper sense, the following methods of ship measurement are often incorrectly referred to as such:

Displacement is the actual total weight of the vessel. It is often expressed in long tons or in metric tons, and is calculated simply by multiplying the volume of the hull below the waterline (ie. the volume of water it is displacing) by the density of the water. (Note that the density will depend on whether the vessel is in fresh or salt water, or is in the tropics, where water is warmer and hence less dense.) For example, in sea water, first determine the volume of the submerged portion of the hull as follows: Multiply its length by its breadth and the draft, all in feet. Then multiply the product thereby obtained by the block coefficient of the hull to get the hull volume in cubic feet. Then multiply this figure by 64 (the weight of one cubic foot of seawater) to get the weight of the ship in pounds; or divide by 35 to calculate the weight in long tons. Using the SI or metric system : displacement (in tonnes) is volume (in m3) multiplied by the specific gravity of sea water (1.025 nominally).

The word "displacement" arises from the basic physical law, discovered by Archimedes, that the weight of a floating object equates exactly to that of the water which would otherwise occupy the "hole in the water" displaced by the ship.

Lightship measures the actual weight of the ship with no fuel, passengers, cargo, water, etc. on board.

Deadweight (often abbreviated as DWT for deadweight tonnes) is the displacement at any loaded condition minus the lightship weight. It includes the crew, passengers, cargo, fuel, water, and stores. Like Displacement, it is often expressed in long tons or in metric tons.

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DickyD

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Re: displacement of HMY Britannia (1893)
« Reply #10 on: September 11, 2007, 08:48:29 AM »

221 imperial tons = 224.547 metric tonnes. O0
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roycv

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Re: displacement of HMY Britannia (1893)
« Reply #11 on: September 11, 2007, 09:33:50 PM »

Hi all I am beginning to doubt the displacement as being 221 tons.  A figure of 140 - 150 tons seems much more in keeping with the other boats she raced with. 

In 1899 the Americas cup boats were in the same displacement bracket above.  The 10 x "J" class boats ranged from 128 tons to 166 tons and were of a comparable size to Britannia.

Another point is that if one is working a boat up to race condition against a known boat (Britannia) it is not a good comparison if the other boat is only 60% of the displacement of the stalking horse.
I think logic wins out the 221 grt taken as a displacement figure is too much at variance with the other boats.  I think a figure of 140 - 150 tons is more likely.

If our friend has plans perhaps he can calculate the model plans displacement at 1 : 30 scale, using the prismatic coefficient.  ( Area of the underwater centre section X the w/l length X factor of 0.5 or 0.55)

I have a close to scale sailing model of the Endeavour(1934, 143 tons disp.)  The Amati plans look good to me and the model plan displacement at the scale of 1 : 35 came out at 7.6 lbs. (3.45 kgms.)  By simple calculation (35/30 X 7.6 lbs) an increase in scale to 1 :30 comes out at 8.8lbs. (4 kgms)

The 7.6 lbs figure was arrived at by calculation from the plans, if multiplied up by the scale of 1 ; 35 it comes to 145 tons which is pretty close.
 
Perhaps this comparison may help, but good luck and do show us the pictures when you build,
regards to all Roy
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vwlucas

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Re: displacement of HMY Britannia (1893)
« Reply #12 on: September 12, 2007, 07:12:51 AM »

 O0

Of course, it helps!

Thanks a lot.
But, you know, I am hesitating with the construction of a french cotter (pilote du Havre) even from the end of the 19th century.
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tigertiger

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Re: displacement of HMY Britannia (1893)
« Reply #13 on: September 12, 2007, 08:33:10 AM »

I have Marine Modelling plan MAR 2530 for Britannia

They quote.
LOA 45.6m
Draught 4.6m
Beam 7m
Waterline to topsail peak 49.3m (this was her 1926 rig, her tallest gaff rig before her final bermuda rig)
Displacement 156.5 tonnes

Hope this helps.

TT

P.S. Looking at Bunkerbarge's post, I assume that a GRT of 221 is still feasible.
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vwlucas

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Re: displacement of HMY Britannia (1893)
« Reply #14 on: September 12, 2007, 10:03:08 AM »

Hello,

With those informations, I get almost the same results: a displacement of about 5.5 Kg for a model.

With the method of roycv, (prismatic coef. of 0.55) a displacement of 145 Tons, far away from the 221 tons... ::)

Well, roycv, the ratio scale/displacement is not linear, but equal to (scale) exponent 3.
If the displacement of a model 1/35 = 3.45 Kg,
The displacement of the same model on scale 1/30 will be 3.45 Kg x (35/30) = 5.47 Kg

Quote
[I have a close to scale sailing model of the Endeavour(1934, 143 tons disp.)  The Amati plans look good to me and the model plan displacement at the scale of 1 : 35 came out at 7.6 lbs. (3.45 kgms.)  By simple calculation (35/30 X 7.6 lbs) an increase in scale to 1 :30 comes out at 8.8lbs. (4 kgms)
/quote]
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roycv

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Re: displacement of HMY Britannia (1893)
« Reply #15 on: September 12, 2007, 06:41:24 PM »

Hi VW, I agree, silly mistake on my part!
My Endeavour at 1 : 35 scale has an extra thickness of 3mms in hull planking plus an extra thick keel and this takes the displacement to 5kgrms and at this displacement and with a sailing keel (Graupner part I think about 1.5kgms.but as used on Libera Ocean kit) giving a draft of 300 mms.
This performs very well in light airs.  Looks fantastic!!!  I take off the quadrilateral jib when it gets windy and then she sails like a IOM.
regards Roy
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