Sponsons

[Randal R Largent]

Can someone give a defination for sponson? I think I have figured it
out but am not sure
Randy

[Derek Warner]

Evening Randy - when I read your question I thought well I think I know
what a "sponson " is in marine terms, but rather than reply looked up the
definition of the word in the Oxford Concise - (Thumb Index Edition)
dictionary - and according to the renound text I was totally wrong - and I
quote :-

the 3rd definition of a sponson "a triangular platform supporting the wheel
on a paddle steamer" [19th century : origin unknown]

I had always assumed that a sponson was roughly triangular in shape and
when combined as a pair - one aft and on fwd supported the paddle box which
covered the paddle wheel on either side of the vessel ??!!

So where does this leave me with PS Decoy?? - about all I can say is that
she was originally built in Glasgow and that's a long way from Oxford so her
sponsons will not be in accordance with the British Dictionary and so
support the paddelbox's and not the wheel's

Does any paddlkeduck have a copy of that famous {i think} American
"Websters" dictionary - what does it say about sponsons? - regards Derek

[Paulrjordan]

Word search "sponson" generates the following result in:
http://www.wordsmyth.net/
which is an online resource I find quite useful.

"sponson"
Syllables: spon-son
Noun
Definition 1. A structure projecting from the side of a ship or boat,
esp. a gun platform, or an air chamber on the gunwale of a canoe that
prevents capsizing.

Definition 2. An air-filled projection on the hull of a seaplane that
ensures stability in the water.

There is little doubt that in paddler parlance, "sponson" refers to
the structure on either side of a hull which supports a paddlebox, a
part of the superstructure, or housing which encloses a paddlewheel.
It may also very well act as a support for the outboard end of a
paddlewheel shaft. The term seems to apply only to sidewheelers and I
have never seen it applied to sternwheelers.

PJ

[HBelflower]

In my past life, I was a seaplane pilot for the US Navy. As such, I became
interested and aware of the use of sponsons on seaplanes. The most famous
use was on the Pan Am China "Clippers" of the 30's and were protrusions from
the hull at each side and at the approximate center and were designed to
provide addirional buoyancy as the plane heeled. Their purpose was to add
additional lateral stability. They served much the same purpose as wing
floats and the outriggers on canoes. I would tend to comjecture that the
weight of the side paddles, so far out from the center of buoyancy. was what
prompted the use of the sponsons. In a turn the ship would heel to the
outside and the weigh of the paddle box would accentuate that tendency. A
sponson would provide the additional buoyancy needed to prevent the ship form
capsizing. Seaplanes ahd a very definite tendency to be laterally unsatble
on the water and required floats or sponsons to prenevt them from capsizing.

Harry B.

[Paulrjordan]

Hi Harry:

Its an interesting point you make, although my only difficulty is that
I've never seen any floatation actually BUILT into sidewheeler
sponsons. In fact the sponson on a sideweheeler doesnt even touch the
water. (or at least shouldn't!) You're right in pointing out they have
been associated with floatation and stability on seaplanes and I'm
trying to figure out why the term would have been applied to
sidewheelers. I have seen some pictures of civil war ironclads which
had bulbous structures running for and aft along each side of the hull
which have been called "sponsons"..but there wasn't a paddlewheel in
site.

Now you've got me scratching my head over this one!!!

PJ

[Randal R Largent]

Thanks for the responses. I would hope the more I learn would eventually
produce a good model.
I live near Detroit, Michigan and have just lately started looking for
info/plans on the rail ferry Great Western that was built in Glasgow in
1866, shipped to Canada in pieces and assembled there. Moved train cars
between Windsor and Detroit.
Can you share where you found plans for your PS Decoy? Do you think it
is possible that some still exist in Scotland for the GW? I called our
Dossins Museum today and the Curator for the library there will be out on
sick leave for at least the next 2 weeks so that resource is on hold for
now.
Thanks
Randy

[Paulrjordan]

Randy:

A good angle of research will be through the Railroad guys if you can
identify which Railway owned the ferry. Almost every Railroad in the
world has an email newsgroup now and there are some very knowledgable
people on Canadian Railways.

The National Archives of Canada might well have more information and
images if this ship if it was owned by a Canadian railroad.

Keep us posted

PJ

[HBelflower]

Hi P.J.

You raise some interesting points, also. My head can always use a good
scratching.

The sponsons on a seaplane do not touch the water except when the plane is at
rest and then only slightly. If she tips or if the seas are rather rough,
then that's another matter.

Also, remembered that on racing hydroplanes the two outer sections of the
hull that the boat planes on are called sponsons. There is a tunnel between
them to provide relatively undisturbed water for the prop to act upon.

Was not aware of the bulbous sides of the CW craft but sounds reasonable
particularly if they were designed to operate as shallow draft vessels in
coastal and delta waters.

Large ships such as super tankers and navy cruisers and battleships had a
bulbous bow to provide additional buoyancy to that thin bow profile. Was not
a sponson but served a similar purpopse except on the pitch axis rather the
roll (longitudinal) axis.

Harry

[woodburner]

Sponson? They dont float, add to stability issues, but are neccesary to attach and support paddle housing to the side of a hull. On river steamers they extend along the entire lenth of a hull, sometimes with cabins or superstructure, as a means to broaden the commercial and renumaretive space beyongd the hull beam. On seagoing vessels they are confined to the areas immediately fore and aft of the wheel and housing.

Dont know anything about the name or such, but do know they wont do the baby's diapers.

Jim

[george britnell]

Gentlemen:

In regards to the item "sponson", several information sources have
the same type of descriptions of this word. They all list bouyant
outriggers of one sort or another but Inforplease also adds:
A structure projecting from the side or main deck of a vessel to
support a gun or the outer edge of a paddlebox.
Webster even goes a little farther by saying: (Shipbuilding): One of
the triangular platforms in front of or abaft the paddleboxes of a
steamboat.
I think everyone who answered was looking to hard and was trying to
imagine a paddlewheel vessel with some kind of outrigger flotation
device, when in reality I think by the descriptions that these are
nothing more than some type of triangular gusset or projecting beam
with possibly a triangular gusset that supports the paddlebox at both
ends of the arc.
I hope my two cents worth sheds a little light on this subject.

George D. Britnell (Suter builder)

[Derek Warner]

George - I would have to disagree with your comments as only 2 cents worth
here and suggest say 10 out of 10 for correctness - but then again that is
only
my two cents worth - regards Derek