Paddlewheel speed on PS Industry

[dragoncity]

Hi All !,
Since my successful launching of P.S Industry I have been experimenting with different
pulley sizes to test paddlewheel speed verses boat speed.

( as a preamble to this, recall a prior posting from Paul Jordan ( I think) discussing
the problem of syncing two motors speeds )

P.S Industry is running two Ford XD windscreen wiper motors, which I thought were rated at 50RPM,
however further tests discover only 30 RPM on ONE motor and 29 RPM on the other.
( wont go into the tech reasons why I thought 50 was the RPM)

You might not think 1 RPM would cause much of a problem would you :-)

WELL IT DOES !!!

The higher the final paddlewheel speed I asked for , using higher ratio pulleys , and was given with question
from the drive motors,
the FURTHER OUT OF SYNC the paddlewheels became., until they were almost 10-15% different in speed.

At some point this caused the boat to 'dig in' on one side, causing mild alarm as the water
is two meters deep and bloody cold !! The sponsons were clearly being pushed down on the slow paddle side,
as the higher speed paddle tried to overcome the drag on the other side of the boat. I originally thought
that I was taking on water and flooding was the cause, there was some water in the hull but this was that
thrown in by the higher speed paddles and not much water was evident.

I've since lined the paddleboxes to stop this water. The boxes are constructed out of perforated metal sheet and
high speed thrashing would force water thru the perfs. , the boat now runs dry again.

So using the motor speed differences, I recomputed the pulley sizes and made a set @ 76 and 79 mm diameter
resp., placing the larger on the 'slow' motor, this evened out the base motor differences and the boat now
runs straight and true. Fortuantely I dont have to worry about the possibility of different motor speeds via
a speed controller -- theres only FULL ON or FULL STOP.

I'm still unsure just what speed I really need as the boat seems quite happy at any speed. Even on the very windy
day with low speed gearing ( 80-90 RPM) the boat still made headway, its not a race boat with the higher gear
(150-160 RPM ), but I wonder how much power is being lost to thrash.

More experiments required !!

Cheers





Brett S Hallett

[Derek Warner]

on Friday, September 13, 2002 10:55 PM - Brett S Hallett wrote

P.S Industry is running two Ford XD windscreen wiper motors, however further tests discover
30 RPM on ONE motor and 29 RPM on the other.

You might not think 1 RPM would cause much of a problem would you - WELL IT DOES !!!
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

Wiper motors are designed with a single ball bearing located in a pressed dish in the motor casing endplate

The exicitation of the armature fields draw's the armature shaft in the direction of the ball bearing - naturally
the armature shaft has a small centre drilling which locates on the ball bearing

I borrowed a digital photo tachometer & checked Decoys single wiper motor, in one direction the display was
locked on 30.00 RPM - in the opposite direction we achieved a ranging 29.00 > 29.80 RPM - I assume that it's
all to do with the EMF/thrust not being contained by the ball bearing [so we should call this going backwards]

So this didn't concern me greatly until I realised the planned drive for Decoy [going FWD] will be with the motor
[GOING] BACKWARDS

I did consider inverting the motor so as for Decoy to go FWD the motor does too, however this would raised the
COG by 0.9 kg, 60 mm higher than planned - so I scrapped that idea

regards Derek

[dragoncity]

Derek, Thanks for your information in digest #434,
I had not considered that reversing the motor would affect the
RPM's -- and of course in my two motor set up ONE of the motors is always
going in reverse, no matter which way the boat is going!.

As I don't expect to be sailing too far in reverse the differences experienced with paddles speed
are now not a major problem, the forward speed being sorted out with differing pulley sizes.

I should mention the benefits of dual motor drive :

1) better direction control of the boat even in a strong cross wind.

-- by stopping the windward paddle the boat vectors nicely in the desired direction.
I sailed the boat around an 'Olympic' racing course without problems in quite strong cross winds
by selectively driving the motors. ( the rudder came along for the ride )

-- fixed shaft driven paddle boats have to turn downwind ( way from the wind) and attempt a full
270 degree turn to make headway if being pushed off course by the wind.

-- by reversing the inside motor I was able to 'insist' that the boat was going to turn into the wind. :-)

2) the ability to stop the boat , and turn in its own length is really nice. Especially when working
small creeks and narrow channels.

3) if a motor 'conks out' , you should be able to limp home.

I can under stand your reluctance to invert the motor , thus raising the CofG, just to get 1 RPM.

Cheers,
Brett

[Derek Warner]

on Tuesday, September 17, 2002 9:14 AM, Brett S Hallett wrote

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
As I don't expect to be sailing too far in reverse the differences experienced with paddles speed
are now not a major problem, the forward speed being sorted out with differing pulley sizes
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
Hi Brett - the model of Decoy is marginally smaller than your model of Industry, and hence I cannot fit two
of the chosen motors - however all of the advantages [with two motors] you note are reinforcing original
postings by PJ and more lately Stuart re the same subject etc

An interesting point is that many of the photographs we can download of UK paddlers have a significant
number of shots of paddlers reversing out from wharves [and many at great shaft speed or should I say thrust]

I can only assume that if we were to think of the paddler in the light our car but being steered by the rear
wheels - and I am sure many would have had the chance to (ATTEMPT) to drive a rear wheel steer vehicle

So if Industry were moored at a wharf, the only way to get her away without damaging the wheels would be
to reverse out - or am I missing something??
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
by stopping the windward paddle the boat vectors nicely in the desired direction.
sailed the boat around an 'Olympic' racing course without problems in quite strong cross winds
by selectively driving the motors
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
Windage is an issue I considered from day one [prior to selecting Decoy - and I naturally have needed
/gone for a grossly over scale rudder] you have a greater issue with Industry, but just imagine the windage
on a model of PS Marion!!!!!!!!!! - regards Derek

[dragoncity]

On 25 Sep 2002, at 9:44, Paddleducks@yahoogroups.com wrote:

> Message: 3
> Date: Wed, 25 Sep 2002 16:58:20 +1000
> From: "Derek Warner" <derekwarner@bigpond.com>
> Subject: Fw: Re: P.S Industry PaddleSpeed
>
> on Tuesday, September 17, 2002 9:14 AM, Brett S Hallett wrote
>
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
> As I don't expect to be sailing too far in reverse the differences experienced with paddles speed
> are now not a major problem, the forward speed being sorted out with differing pulley sizes
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

> Hi Brett - the model of Decoy is marginally smaller than your model of Industry, and hence I cannot fit two
> of the chosen motors - however all of the advantages [with two motors] you note are reinforcing original
> postings by PJ and more lately Stuart re the same subject etc

Should have made a bigger boat !! :-)
>
> An interesting point is that many of the photographs we can download of UK paddlers have a significant
> number of shots of paddlers reversing out from wharves [and many at great shaft speed or should I say thrust]
>
Yes, I saw a (still) photo of the P.S. HYGEA leaving the wharf at Melbourne at very high speed , the water thrash
was tremendous. This boat was reputed to be able to do 22 Knots, and infact was scheduled to run at 18Knots !
The HYGEA & OZONE were both Clyde built boats for the Port Philip Bay tourist routes and considered the most
beautiful boats to have worked the Australian waters.

Murray River Paddles have a beauty of a different kind :-)

> I can only assume that if we were to think of the paddler in the light our car but being steered by the rear
> wheels - and I am sure many would have had the chance to (ATTEMPT) to drive a rear wheel steer vehicle
>
> So if Industry were moored at a wharf, the only way to get her away without damaging the wheels would be
> to reverse out - or am I missing something??

Dont know about the full sized Industry as I have no info about its motor setup. However I did obverse the
P.S Alexander Arbuthnot , which does NOT have differential paddles, leaving the wharf at Echuca. At the
time she was moored closely in front of P.S. Pevensey and close to land on her bow. ( a bit like a car parking space
with a car at the front and back). To get out, they had a rope attached to the wharf about 3/4's along the hull
(aft of the paddlebox) , started the paddles in forward, and the bow just gently swung out into the river, dropped the
rope and away we went.

Now turning the boat, (doing a U-turn) in a narrow water way was just lovely. We were heading downsteam in the
middle of the river, slowed down and steered the boat so that it was at right angles to the steam,
stopped engines, and gently 'lent' the bow against the bank and let the current do the work of turning the hull,
started engines and headed back up stream. Only took a couple of minutes, and done soo gently.
And typically, everybody (me included), went to the bank side to see if the paddles would hit the ground !
They did'nt, but the boat did heal considerably.

Our foreign paddleduckers may not know that the Murray River is very long but not very wide.


======
With MY P.S Industry, if moored along side the bank ( eg a pool wall) , I simply use full opposite rudder, eg if
moored on PORT side use STARBOARD rudder, and then turn on the motors. The boat simply begins to rotate
on the spot, probably touching the stern against the bank , and once the bow is clea, full ahead!

The manouverably of twin motors setups is terrific.

As far as space is concerned I've been looking at side window winder motors as they are very narrow, about 30mm
along the 'flat side' and also have a gearbox fitted. So one could fit them end-to-end without much trouble, however,
the one I've been playing with turns at 3700 RPM reduced to about 100 via the gearbox, BUT, its final drive fitting
is a turning gear, not the shaft! Sso I have not figured out how to drive off the gear. The window winder itself has an
effective gear ( a flat curved arc operating the crossed arms to lift the glass ) of many centimeters, probably 1/2
meter or more !!

> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
> by stopping the windward paddle the boat vectors nicely in the desired direction.
> sailed the boat around an 'Olympic' racing course without problems in quite strong cross winds
> by selectively driving the motors
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
> Windage is an issue I considered from day one [prior to selecting Decoy - and I naturally have needed
> /gone for a grossly over scale rudder] you have a greater issue with Industry, but just imagine the windage
> on a model of PS Marion!!!!!!!!!! - regards Derek
>
AH! Yes, P.S. Marion. She must be a real handfull in a blow!. Considering she has a hull of similar dimensions
to the Industry one does wonder about her stability at three deck levels.

On my model of Industry I left the Engine bay clear and theres a gap on the second deck where the stair well
and funnel comes through, so I assume that I'm getting some windage pressure relief even tho theres quite
a bit of infostructure. Marion does not have this feature and would offer a solid side to the wind.
>


Brett S Hallett