Paddleducks
Old Yahoo Group => Yahoo Messages => Topic started by: mstecker2002 on June 18, 2005, 02:30:31 AM
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Has anyone built the Dumas Mt. Washington paddlewheeler? I am considering getting one and would be interested in comments on its quality, running characteristics and required modifications. I have read that it has a stability problem on the water and that the paddle system should be ventilated. However, I have never seen an explanation on what ventilation entails. Is it drilling holes through the individual paddles or is it making holes in the paddle wheel housing or what? Any comments would be appreciated as Dumas denies any problems with the boat.
Michael Stecker
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Hi Michael..and to all those considering the Dumas "Mount Washington"
First of all, I have never built the model but I have been offered
completed examples on two occasions...both times (after much
agonizing)I said "no". The reason is exactly as you suspect.
According to some owners, this model has inherent instability and
handling problems when completed. However, before we go any further
I do not want in any way to detract from the beauty of the finished
model as a static display. Dumas have done a good job of capturing
the original vessel and it looks very attractive in a living room
because it's not too large even at 44"...
Take a look in our files section at the photo:
http://groups.yahoo.com/group/Paddleducks/files/
The hull has very little freeboard, and the superstructure is fairly
substantial...although not nearly as much so as most American
sideweheelers. Dumas provides material for building the
superstructure which is overscale and results in a center of gravity
which is far too high for the model. According to modelers in Toronto
Canada, the "Mount Washington" develops a distinctive heel which can
only be corrected by stopping the vessel and waiting for it to
stabilize. You can imagine the thrust dynamics on a hull when one
paddle is almost clear of the water, and it apparently takes very
little to clear the floats of the surface. Not surprisingly there
have also been reports of much "waddling" and one enterprising
modeler in Toronto even resorted to an underwater rig to stabilize
the model. Apparently it worked, but made the model look perplexing
(to say the least) when it was out of the water.
> the paddle system should be ventilated. However, I have never seen
> an explanation on what ventilation entails.
Paddle box ventilation has existed on virtually all sidewheelers (and
shrouded sternwheelers too)because the compression of air and water
in the paddlebox is so substantial and if left unvented can
apparently create a suction on the surface of the water which, in the
case of a sidewheeler, causes the the ship to heel. This also occurs
in models. I'd like some of our engineering experts to comment
further on this, as it's something I read somewhere but can no longer
find the reference to.
>Is it drilling holes through the individual paddles or is it making
>holes in the paddle wheel housing or what?
Well, drilling vent holes in the side of the paddlebox would work,
but since paddleboxes are also objects of artistic beauty, the vents
often follow the form of the design, and appear in many wonderful
shapes. From what I recall, Dumas merely simulates vents on the
paddleboxes of "Mount Washington" although you can see them clearly
on prototype pictures. To cut them in is quite a modeling challenge
but with the help of drills, a few small files, and lots of patience
the vents can be cut to correspond to the original ship. It really
does add visually and functionally to a model.
>Any comments would be appreciated as Dumas denies any problems with
>the boat.
Yes, I would not expect Dumas to comment negatively on their product
and again, notwithstanding the handling and stability issues, it's a
fine kit. Building operating model sidewheelers is much more than
just building a nice looking ship (screw vessels are much more
forgiving) and if you read back over early posts in this forum you
will read about the problems and solutions for building good "water
performers". "Mount Washington" can really only be built to run
effectively if the superstructure weight is cut down considerably
with the use of 1/32 material and keeping the COG very low in the
model.
I do hope this gave you a little more insight to the model and please
dont hesitate to ask if you need any more information.
PJ
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Michael,
I recently saw a 'snippet' in a magazine re: Mount Washington,( cant remember which one
as I was browsing at my local newsstands "library" !) where the
builder had built in a counter weight servo that moved a weighted arm 'into' the turn to
counterbalance the tendency to excessive heal. This servo was 'Y' leaded to the rudder servo
channel and therfoe moved automatically.
He simply fitted a medium size length of all_thread to a servo arm aligned
along the center line of the boat, ie: when rudder centered so is the counter weight,
using a few nuts as the counter weights fitted to the extreme
free end of the all-thread.
He seemed pleased with the results, I think it was from a model boat competition report,
so it must have solved the boats handling problems, if it was competing.
Good luck, it looks like a very nice model from the photos I've seen.
Cheers,
Brett
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Brett:
I too vaguely remember this technique and believe it was reported in RC Boat
Modeler magazine. I may be mistaken and would like to know where to get the
article and contact the author. Also, I wonder what Paul Jordan and other
experts on the list think of this counter-weight technique to stabilize the
Dumas Mt. Washington.
Michael Stecker