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Author Topic: Thames Barge  (Read 21112 times)

wideawake

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Re: Thames Barge
« Reply #25 on: October 23, 2008, 02:28:54 PM »

I agree on the scaling issues with the leeboards, and the need for a drop keel.

and are maybe relying on the hatch coamings to keep them afloat. I would imagine that in the pre-regulated days of river haulage, similar practices were common on the Thames.

Did the full size barges heel, or was this something that the skipper would try his hardest to prevent; assuming payload was more valued than speed.

Any insights would be greatly recieved.


I think you're right, that payload was the important thing and that fully loaded they were fairly "stiff".  I guess that they would be trimmed and sailed differently during the famous Thames Barge Races and would certainly have heeled a fair amount then when driven hard.

As I've mentioned before, there's a lot of interesting and useful info on Ivor Bittle's website regarding the way full-size barges were worked and how to best achieve a simlar sailing style in a model.  http://www.ivorbittle.co.uk

I think it would be fair to say that Ivor believes that the object should be to build a barge which looks as close to scale as possible both in terms of fittings, sailing characteristics and presence on the water but that invisible materials are not important, whereas some of the racing model barges are "stand-off scale" with fittings and rigging compromised to improve racing performance.
Both valid PoV but leading to very different appproaches.

Cheers

Guy
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Tom@Crewe

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Re: Thames Barge
« Reply #26 on: October 23, 2008, 02:54:40 PM »

thanks for the help and pictures.

I have not fitted a motor or working leeboards or any detailing as its a test piece, if I like sailing it i will go for something more scale, if I don't like sailing it was just a cheap test.

but I am looking forward to getting it to the lake.


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papa

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Re: Thames Barge
« Reply #27 on: October 23, 2008, 07:27:27 PM »

My greeting for everybody :-)

I would like to build this ark with my sons, but I would have a question.
It is possible to see the motive servo of the vitorlázat on one of the pictures, but there is an electric motor beside it.
Its role is unclear.
In the deficiency of edge motorcyclist drive?

With a greeting Elf Daddy ok2
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andrewh

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Re: Thames Barge
« Reply #28 on: October 24, 2008, 06:39:00 AM »

hello elf daddy

The motor in the picture drives a propellor to bring the boat home if it is needed! 
It operates from another channel of the radio, but when sailing it is always "off"

This would be a good boat to build with your sons; many people, including Tom@crewe have built it in plywood.  Mine is made out of styrene

andrew
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Tom@Crewe

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Re: Thames Barge
« Reply #29 on: October 26, 2008, 09:25:23 AM »

My next question. Having increased the length of the model, the buoyancy has increased as well, therefore the keel needs to be heavier.

The waterline is not on the plan but looking at other models and the real thing I'm looking a half way from the bottom of the hull to the deck line (Is that about right?) I'm going to put her in the bath weigh her down to water line, weigh the ballast and thats the weight of the keel.

BUT........where do I fit the keel. A) as the plan under the mast and I suppose under the thrust! then add weight to the stern to trim the boat.
or B) move the keel back to a position where the boat is in trim.
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wideawake

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Re: Thames Barge
« Reply #30 on: October 26, 2008, 09:42:18 AM »

Hi Tom

At the risk of repeating myself, this info and also a good deal of theory is on Ivor Bittle's website www.ivorbittle.co.uk in the "Modelling a thames Barge" section.   WRT position of the keel, Ivor suggests that the centre of area of the fin should be just over 40% of the LWL length back from the stem.   Another source suggests that the front edge of the keel should be about half way back the mainmast.   I've not checked whether this is the same place on my LD plan!   If you're keen to experiment it should berelatively easy to devise a mount which allows the position to be adjusted to find the best position in practice.

Apart from Ivor's website there was a very useful series on building the Clai Jane by Ivor Warne (too many Ivors!) in MB a few years ago and he has written a couple of update articles, the most recent of which is in the latest MB which have lots of useful info gained from his experience of trying to get CJ to sail less like a waterlogged pig  :-)

HTH

Guy

Guy
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George Steele

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Re: Thames Barge
« Reply #31 on: November 16, 2008, 07:56:16 PM »

Hello, maybe this is a dumb question but here goes:  I read somewhere (Tristan Jones?) that off the wind barges set a square sail (and perhaps a square topsail). Is this accurate and if so do any of you sett one on your models?
                     Thanks
                                   George
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farrow

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Re: Thames Barge
« Reply #32 on: November 30, 2008, 10:44:38 PM »

I was taught how to sail; the real thing by a very respected professional barge master. The barge in river trade between medway and the Thames used to load with a 3 inch freeboard, when the Board of trade introduced loadlines for the Essex and coastal work it was 6/9 inch's freeboard depending on the area it was going to work in. The barges had a peculiar lean in a strong wind, in that they did not heal on their midships but more on their lee chine. After all they were literally planks going along, with extremely shallow draft to a massive beam to length ratio, the Mirosa was 82 feet long with a 12 foot beam and a moulded draft of 5foot 6 inch's if my memory serves me right. Also most of the main masts were of similar size due to racing regulations, their gear was not massive, unlike the champion bowsprit introduced after the war for 4 barges which had an increase of over 50% and which one of their racing masters commented as " yes she leans further, but she does not go any faster".
The Sirdar in her racing gear had heavy chains suspended on wires in the hold to alter the trim when racing, whilst Everad put a forklifter in his barges, also when the Veronica was ug out of the seawall to race after Sirdar thrashed Sara, all her frames were half sized and some of the lining from inside the hold was missing so as to make her light for speed. Also the Sara left the PLA motor launch in mucking reach standing when she was sailing once.
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farrow

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Re: Thames Barge
« Reply #33 on: January 07, 2009, 10:08:11 PM »

The very early Thames barges in the early to mid 19th century did used to set a square sail when running of the wind, similiar practice to RN schooners of that period. There are several paintings of the thames showing barges with this type of square sail.
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wideawake

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Re: Thames Barge
« Reply #34 on: January 09, 2009, 05:30:32 PM »

Hi all

Just using this Thames Barge thread to pass on some useful info from the latest AMBO mag "Bitts and Bobs".    The moulds for the highly thought of hulls produced by the late Tony Williams have been taken over by Terry Moffat of AMBO and the Southend Club.   Terry can be contacted by email for info regarding production plans etc at terrymoffat@blueyonder.co.uk

HTH

Guy
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JayDee

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    • JOHN DOWD
Re: Thames Barge
« Reply #35 on: January 09, 2009, 07:24:50 PM »


Hello,

Fitting a drop Keel to a yacht of any kind, is usually done with the boat ballasted down onto the water lines, fore and aft.
The Rudder must be fitted, Lee boards if to be used, be fitted and in the water.
The Centre of Lateral Resistance  (CLR)  has to be found.
The boat should be pushed sideways with a Pencil or other pointed object.
Find the point where the boat can be moved bodily sideways, moving the Bow and the Stern equally, is the CLR !!.
The centre of the Keel area is the same point as the CLR.

John.  :-))
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farrow

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Re: Thames Barge
« Reply #36 on: January 11, 2009, 11:17:55 PM »

Hi Tiger Tiger,
As an aside, I know nothing about how the Thames barges plied their trade. The barges here in China may have little draft when empty, but are loaded up until they have little if any freeboot at all. I have seen some that appear to be up/down to the scuppers and are maybe relying on the hatch coamings to keep them afloat. I would imagine that in the pre-regulated days of river haulage, similar practices were common on the Thames.

In answer to your query above, the answer is the same as china, in the London river the PLA allowed minimum freeboard was 3 inch's and about 6 inch's on the coast before the Board of Trade took an interest in their freeboards. The more you carried the more you was paid as the crew were paid 50% of the freight rate per ton after agreed stoppages such as dock dues etc. Have seen loaded Thames Lighters with water on deck. As to leaning over to much in a breeze, well yes as a barge it is dangerous to get water on deck, as your stability curve rapidiliy disappears. So the master would reduce sail area as appropiate, but in relation to thier hull size the working sail areas of trading barges was not that particulary big in comparasion to say schooners and fishing boats. Several barges in trade did capsize , one famousily after a Thame race in a private match, in which both master and owner drowned. One caught its leeboard in shallow water, the leeboard did not break and the barge tipped over on it.
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prof charles

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Re: Thames Barge
« Reply #37 on: January 19, 2009, 09:57:39 AM »

I have built and sailed two versions of the HFM kit (thames barge) and I still sail my Ethel Ada which is based at maldon, the real thing that is, you do not need an expensive servo or sail winch just a mid range one with a arm does the trick, the only thing I did to mine to make them go right was to fit an extention to the rudder (bottom) about 2 inches, if you make it bigger it starts to act as a brake, its a first class bit of gear to start of with,
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Tom@Crewe

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Re: Thames Barge
« Reply #38 on: January 20, 2009, 08:31:53 PM »

Not quite finished but...................................
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tigertiger

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Re: Thames Barge
« Reply #39 on: January 21, 2009, 01:00:20 AM »

Looking good. 8)
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Ivor Bittle

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Re: Thames Barge
« Reply #40 on: August 13, 2009, 06:22:27 PM »

You might care to read www.ivorbittle.co.uk
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herrmill

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Re: Thames Barge
« Reply #41 on: August 15, 2009, 01:35:48 PM »

You might care to read www.ivorbittle.co.uk

That's an excellent site for any builder, barge or otherwise.  :-))
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MCR

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Re: Thames Barge
« Reply #42 on: August 19, 2009, 09:40:21 AM »

Just got back from the USA read the thread with interest this is my effort ,built on an Ian Williams hull which I think are now available again after his sad loss.
AMBO is the way to go I joined for the period of the build the people involved couldn't have been more helpful.
I love sailing this boat with a 8lb keel she can sail in just about any conditions
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Greggy1964

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Re: Thames Barge
« Reply #43 on: September 05, 2009, 03:13:58 PM »

There is an old book called Spritsail Barges of Thames and Medway by Edgar J March ISBN-13: 9780715346815  written back in the 50's which has detailed plans and sketches of these ships that would be a great use to you.

Hull central Library has a copy of this book and it can still be bought but its quite pricey as copies are rare.

Regards
Greg
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Ivor Bittle

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Re: Thames Barge
« Reply #44 on: September 08, 2009, 07:09:31 PM »

This thread has had a long run and is now current again.

I noticed the contribution in which it was claimed that the position of the dynamic transverse thrust produced by the hull when it is under way can be found by dragging the floating hull sideways (or pushing it)

I watched a lady sailing a model barge fitted with a keel that had been located by this pushing sideways method. It was hopeless in that it turned into wind continually. The position of the keel was changed and it is now a much better boat.

Only a supreme optimist would think that a dynamic force can be found from a static test.

If the keel that is added to a model barge is of a satisfactory aerofoil shape it is so powerful compared with the hull that it is effectively the only component resisting the transverse force. Then the whole idea of a centre of lateral area collapses. As it is the keel that is resisting the transverse force and not the hull it follows that the new keel must be fitted relative to the sailing rig that is position-fixed for a scale model of a barge. I covered the location of keel in my web site. www.ivorbittle.co.uk

Of course the TSB had a drop keel only it was called a lee-board. With a crew of only two there was an incentive to set the barge up to let it sail long distances under automatic steering and getting the boat balanced would facilitate this. I think that the leeboards could have been used to balance the barge because lowering or raising the lee-board also moves its centre of lift fore and aft. In effect it is a movable keel.

Ivor Bittle

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tigertiger

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Re: Thames Barge
« Reply #45 on: September 09, 2009, 12:58:57 AM »

Hi Ivor

I had always assumed a different reason for choice of lee board.
It was a much simpler design and build in days of yore, when boats were very simple, and the tradition continued. Also the keel box would interfere with loading and the size of loads any boat could carry, and so having the keel outboard would make more sense.

Like I say, these are assumptions.

Many other benefits gained in early boat design, before the science of marine engineering, would have been through trial and error and happy accidents.
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Ivor Bittle

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Re: Thames Barge
« Reply #46 on: September 11, 2009, 07:10:21 PM »

The Thames barge had a direct line of descent from the swim headed lighter. Throughout it worked in a tidal river and went to ground when the tide went out. No doubt, as the barge developed it was found to be necessary to limit the leeway and the leeboard came about. I cannot imagine that anyone thought in terms of a centre board.

My point is that the leeboard is moveable and can be used to balance the sailing rig, that is, to get the transverse force generated by the hull and the leeboard in line with the transverse force generated by the rig. This unloads the rudder.

In passing the leeboard came to have a very good section that is very like a thin, symmetrical aerofoil section.

Ivor Bittle
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