Paddleship issues various...

[Derek Warner]

Thanks to all paddleduck responses re motor types - (PJ just put one extra zero in) (but remember it was me who originally provided incorrect Decoy dimensions as ' feet and not " inches!!)

I have a dead VCR so will remove the case to see what I find, alas I threw the dustbuster as the motor was O/C as a result of my youngest daughter trying to vacuum up cotton buds - she denied it but the evidence was jamming the fan

PJ had written once previously but expanded in his e-mail 18/4 @ 2.54 re building - bench testing - bath testing etc etc

From his original text I had intended to build & complete the hull and install the paddle wheels, add the motor and battery/s in loose format then do the bath testing to check for waterline by exerting and noting the force required on the bathroom scales placed midships to bring Decoy down to say best waterline then working backwards the available or required weight of extras etc

I will still follow this general process, however it will not include installation of paddle shaft, shaft plumber blocks or paddles - which will give me more latitude in actual paddle axis location etc

I have gone for 1/4" brass bar for the paddle shaft (which measure 0.249" ID and therefore suitable for 1/4" ZZ double sealed ball races - one each on either side of the shaft V pulley and one each inboard of the hull planking - might be a bit of an overkill but is designed to eliminate the failure or wear of brass rod in brass bushes noted twenty years ago by an other

I have set the outer two bearings up in clamped V blocks and it is surprising the amount of deflection achieved simply by thumb pressure on the shaft extremities (but as PJ suggests this may not be a problem)

Any comment here or on any other possible solutions greatly appreciated

regards - Derek

[Paulrjordan]

Sounds good, Derek..as I said, any time spent on the bench, getting
the engines, batteries, drive train and paddle rotation sorted out
will save so much time and experimentation in the water. The paddle
axis height in relation to the waterline deserves some thought, but I
relied on plans to guide me here.

> I have gone for 1/4" brass bar for the paddle shaft (which measure
>0.249" ID and therefore suitable for 1/4" ZZ double sealed ball
>races - one each on either side of the shaft V pulley and one each
>inboard of the hull planking - might be a bit of an overkill but is
>designed to eliminate the failure or wear of brass rod in brass
>bushes noted twenty years ago by an other


I like the idea of the two ball races here, but again I should point
out you are now working at what I consider a critical weight point
affecting the C of G. Example - I originally had stainless steel
paddle shaft pulleys of approx 2" dia x 1/4" wide. Their weight
immmediately caused the boat to become unstable, so I replaced them
with styrene wheels which proved totally satisfactory. I think
this may have something to do with the fact that many paddle wheelers
have almost flat bottoms and I notice some actually have small bilge
keels. This lesson kept me ever mindful of keeping weight down on the
paddle shaft axis. The reason I mention this, Derek, is that you
might consider ONE ball race each side per axle. Remember if you think
it's "overkill", then it probably is!! The rotation on the paddle
shaft is quite slow and I wouldn't expect shaft heat or friction
(wear) to be a real problem so long as there is some form of
lubrication.

NOW I HAVE AN ADMISSION - I don't run my shafts through ball race
bearings..and I SHOULD !!! I was going to, but on the bench my
"jury rig" with grease-filled sleeved bearings worked so well, I
didn't think I needed to alter them and I also figured my paddler
would be doing a fraction of the running time of its prototype. This
system also gave me a watertight through hull fitting for the axle.

Now my thoughts on shafts. I use 1/8 engineering grade stainless
steel shaft in grease filled sleeve bearings. The paddle shaft is
hollow brass and has a collar soldered into it which clamps down on
the axle with a grub screw. I positioned this about 3/4" from
the hull biased towards the inboard side of the wheel. This allows
me to use a short "stubby" axle. (remember to place the grub screw
on a plane BETWEEN two paddle blades so you can access it..which I
failed to do the first time!!) Again I am concerned with weight at the
paddle shaft axis and also to keep weight from creeping outboard, so
my axles are short and supported ONLY through the hull in a 1/2" long
brass sleeve epoxied into a wood carrier block. Because my paddle
wheels are light, there is no undue downward force on the shaft and
this "through hull bushing" appears more than enough to support the
entire axle, pulley, and paddle wheel without end bearings at the
outboard extremities

This has the effect of also doing one thing I consider VERY
IMPORTANT. The ability to REMOVE the paddle wheels once the sponsons
and paddle boxes are on!! I have seen situations on side paddlers
where it was virtually impossible to remove the wheels without major
surgery once the sponsons and paddle boxes were attached. By undoing
the grub screw on the paddle shaft collar, I can slide the "stubby"
axle inboard just enough to "drop" the paddle wheel. If I want to
replace the shaft, I can either undo the grub screw on the collar of
the pulley and slide the shaft outboard or simply pull the shaft
inboard with pulley attached. It's short enough not to foul the
opposite side axle.

I consider this critically important, and I have a diagram somewhere
which I'll try to dig it out and post. Generally I am pleased with my
set up although ANYTHING can be improved..it's called progress!!

Again, Derek, sorry to be so long winded...but you are presently
going through THE most critical phase of side wheeler building..and
once you have this all sorted out correctly, "DECOY" will be a stellar
performer on the water.

Today was meant to be about batteries....oh well!! maniana!!!

PJ