Paddleducks
Old Yahoo Group => Yahoo Messages => Topic started by: vawarner on June 14, 2005, 06:40:02 PM
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I have another question for the experts. Can anyone direct me to a
source that would show details on the area that the paddle boxes
attache to the hulls. The type I am specificaly intersted in are the
long ones that are on warships, with long boats on them, but any one
will do. DK Browns' book "Paddle Warships" talks about this but
doesnt show any drawing or pictures. I am bulding some 1/600 scale
models and all the souces show the side views of ships, which show
good pictues of the outside but not the side that attaches to the
ship. I hope there this isnt to general of a question. A name of a
book ot URL that would show drawings or such would be great.
regards
William Warner
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Hi William - I am responding not as the expert, but also as one who may
benefit by Paddleduck responses
My 1/24 scale PS Decoy has the paddle shaft axis 3/8" below deck level and
the radius of the paddle box will be 2 1/2" above the deck - being an RC
model I need removable access to the engine room - accordingly I can attach
the sponsons & paddle box to the hull only by that same 3/8" to deck level
Irrespective of the materials to be used (styrene, wood or and brass shim)
there will be overhung weight that will have difficulty in being suspended
whilst maintaining structural rigidity
My little book on Australian paddlers show many variations of triangular or
scalloped wooden blocks attached to the hull near down to the waterline thus
suspending the sponson timbers and out to the near extremities of the
paddle box - another variation on this appears to be substituting the
timber blocks with angular pipe supports again between the hull - sponson &
paddlebox etc
The 3 small photographs I have for PS Decoy in the late 1800's were all
taken at such an angle that I cannot see or determine if she had any such
supports - but I plan to use two 1/16" brass rod angular supports for each
paddlebox with the full length of the sponson being supported by 14" long
stringers already attached to the hull sides
I think one of Paddleducks links goes to the PS Wavley rebuild site some
years back (Tom Lee @ virgin.net?) I seem to remember Wavley had similar
metal angular supports
Like you, I would be most interested in the thoughts of others
regards Derek
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Hi William:
It's 3:00 am and a good time to be meandering through Paddleducks
messages which were posted while I was away. I have read all the
responses to your RFI (comment on that later)and here's my take on the
subject.
You wrote... "the area that the paddle boxes attaches to the hulls".
It seems fairly evident from prototype builders' plans that the
paddlebox point of attachment is NOT to the hull, but rather to the
SPONSONS which in turn are integral to the deck and braced
beneath to the hull (In many later passenger steamers, and
particularly American lake sidewheelers, there was no paddlebox per
se, but rather part of the entire superstructure!) Remember, the
weight of the paddlebox has to be born by the sponson/deck rather than
the hull as to do so would impose tremendous strain on it. Now let's
be careful here because you asked specifically about about warships
and I only looked at British Tugs and Excursion Steamers However, I
can't see this would be very different from an engineering standpoint,
although the ships you talk about are probably earlier than the plans
I looked at.
In order to see clearly what I mean you have to look at actual
builders plans showing transversal (cross) sections of the ship
through the sponsons. You will find at least two transversal hull
sections for and aft of the wheels where lateral beams are extended
outboard from the deck to provide the integral aupport of the
sponsons. These are often supported beneath (although not always)
with STRUTS (tubes or angle) or GUSSETS attached diagonally to the
hull and corresponding to inside bulkheads. It is here that the full
weight of the paddlebox can be taken and it's a fairly simple matter
of "resting" and securing the paddleboxes on the sponsons rather than
attaching them to the hull itself.
Now let's turn to modeling. I really do hope I'm not confusing anyone
here, because this is critical to sound MODEL paddlewheeler building.
I have often been surprised at model building articles which show the
paddleboxes and sponsons being constructed AS ONE UNIT and being
attached to the hull AFTERWARDS .. In my opinion this is NOT the
correct way nor is it likely this would have ever happened in
prototype practice ( However, I await some Paddleduck to show me the
error of this rather grandiose ASSUMPTION!)
Simply, in models at least, first build your sponsons integral to your
decks to provide the main support for your paddleboxes. Add the
necessary under bracing to the hull IF it existed in your prototype.
(often purely cosmetic in a model!) I found ships which had no under
bracing and relied for support purely on cross members extending
outboard from the deck and capped by for/aft flanking rails. Build
your paddleboxes and decide if you want them removable or permanently
attached. I favour removable ones if possible for access to the
wheels. It's important to make sure the paddleboxes are watertight
to their respective sponsons. I have often seen silicone used to
seal this troublesome area..and this is totally wrong. There is a way
of making your paddleboxes entirely removable and watertight without
any rubberized seals (another subject). When your paddleboxes are all
in place, you can cap the decks with your bulwarks.
To sum things up, I think our good friend "down Under" Derek (Warner)
caught on to this question immediately. I quote
"Irrespective of the materials to be used (styrene, wood or and brass
shim) there will be overhung weight that will have difficulty in
being suspended whilst maintaining structural rigidity
My little book on Australian paddlers show many variations of
triangular or scalloped wooden blocks attached to the hull near down
to the waterline thus suspending the sponson timbers and out to the
near extremities of the paddle box - another variation on this
appears to be substituting the timber blocks with angular pipe
supports again between the hull - sponson & paddlebox etc
So there it is and as you can see, Derek answered William's question
in a far more succinct way than I just have!
PJ
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Hello everyone, this is Jim Wilke.
I'm no expert, but there may be more synthisis between American and British practice than realized, even in paddle wheel box mountings. Engineers, shipwrights and mechanics were all great readers of the British magazine "Engineering" which was published on both sides of the Atlantic. Descriptions, illustrations and plans of the latest ships, locomotives, bridges, steam engines, mines, canals and other matters of engineering interest were routinely featured in the pages and Britain's lead in engineering matters would lead many American builders to take their approach quite seriously. In addition, many engineers and mechanics, partners in engieering forms and machine shops traveled to England and elsewhere when planing American railroad systems, or to see Brunel's bridges first hand. Certainaly all who could rushed to New York to study the Great Western and Sirus when they arrived within hours of each other in 1839. For those who could not, full descriptions were even published in the American Railroad Journal of 1839 - evidence of great cross pollenization among different works.
Certainally understanding British practice is a great place to start, even if American builders moved towards other solutions. While the Savannah is an American first, it is so isolated that the real advances and standards of contruction and craft is in Britain. Steam locomotive design may offer a model - British locomotives imported to this country in 1830-31, and for a decade after, provided the basic model for American commercial builders to copy and then refine to their own notions of design. The evolution towards a distict American form was more or less complete by 1855, or 25 years after. Just how rapid warship design, or at least warship propulsion, evolved in the states I cannot tell, but it would be governed by the mood of the Naval Review Board, and often the predudices of its members. My hunch is that they were far more conservative than the commercialized and competitive locomotive industry!
So who built the American paddle warships - innovative designer and engineers? Were independant builders allowed to experiment on designs or machinery? Did warship design attempt to Keep up with the Joneses (Britain)and require fast turnaround? Or was the naval board more conservative and look to steam with suspicion, and did shipwrights keep to wooden hulls and apprentice carpenters? Was there the warship building equivalent of a Donald McKay, or Robert Napier?
I find the great joy in modeling is understanding the history of it - approching the same problems in miniature that we once did so long ago. And of course they look really beautiful when afloat, maybe what they thought too.
Jim Wilke
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I want to thank all thsoe who have responded with information for me
to follow up on. It has provided me leads for me to investigate the
subject and I will keep everyne informed about my findings
regards
William Warner
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William,
I thought of something else since last writing - American designs influenced British engineering, though the same trade press, although to a much smaller scale. It occured in locomotive design with the British adoption of outside cylinders and lead trucks, and would have occured in, say, the development of propeller design (esp the Great lakes, where propellers had advantages in canal locks, also the first large British Canadian paddle steamer for the lake service was built in New York) and undoubtedly other fields. But given the British lead in oceanic paddle shipping and naval vessels, consider the British first. Inland was the American perogative, lakes, rivers and such; the open seas and coastal service appear to be British.
Jim