PS Mary Ann by Jeff

[jeff1949]

Hello all,
Just joined Paddleducks, and have already found a lot of great information.

I am interested in building an almost scale Murray River paddle boat based very loosely on the PS Mary Ann, first paddle steamer on the Murray River.

Have read Brett Hallet's detailed build process for his Enterprise and I will be following his methods more or less. About to start planning, so will try and keep members informed of progress.

When I was 15 I built a scale model cabin cruiser but never finished it, although I have lugged it around with me through all my various moves. I am now 66, and I finally completed the boat and motorised it about 2 years ago - and it goes just as well as I hoped it would when I was a kid. 2 channel radio control with a great ESC gives very realistic scale speeds and reverse.

Once I have constructed the hull of Mary Ann I am going to experiment with - wait for it - the motors and gears from an electric side mirror off a car. On the bench the worm drive and gear gives about 120 rpm and seems to have very high torque. The motor is not much more than an inch long, so if a couple of these can push my 1.12metre boat along (with 10.5cm paddles) I will be happy - if not I will use them at a later date for a smaller model.

Would be interested if any other members have tried using these motors/gears?

Will keep you posted - with pics I hope - of my progress with Mary Ann.

Jeff

[derekwarner_decoy]

Hi PD's and welcome Jeff  .....sounds like 1949 was a good year   
It has been years since anyone mentioned any of Bret Hallett's build work, but I have a feeling that Bret himself discusses 12 volt motor vehicle window winder motors.......yes massive torque and the right speed range, however they had a different usage/frequency rating & hence a higher current draw over windscreen wiper motors which are continuously rated and hence the design offers extremely low current consumption...and which were used by Bret & many others

The Many Ann, features descriptively well in 'Ships of the Inland Rivers' by Parsons....[page 100].........the original 1852 vessel built for Randell, was the most celebrated

So, any questions, just post away ............... Derek

[DamienG]

Welcome Jeff. We look forward to your posts and pictures.
Damien.

[jeff1949]

I am brand new to the forum, and about to start a Brett Hallet type construction of PS Mary Ann.

Was wondering today....why are spoked wheels used for the paddles instead of a solid disc?

There must be a very good reason, after all the spoked wheel IS what is used, but I would love to know the advantages.

Making solid discs would be so much easier

[TailUK]

At a guess I'd venture that it's about weight.  A solid wheel of strong enough construction would be considerably heavier than a spoked wheel. 

[jeff1949]

Thanks so much for the warm welcome.

The motors I was referring to are the tiny motors in the electric side rear vision mirrors. I was wondering if anybody had used them before? If not, and if they work, it might start a new trend.

The difficulty will be in aligning the worm drive on the motor shaft with the main gear, but I can make an adjustable platform to do this...I think.

Will keep you posted.
Jeff

[jeff1949]

Sorry if I have this in the wrong place - new member getting used to things.

I mentioned in the new members introduction spot about my probable use of the small motors from car rear view mirrors as drive units for 10.5 cm wheels on a 1.2 metre PS Mary Ann.

Have attached (I hope) a pic of the motor and drive wheel. 60 teeth on the gear, 10 on the worm. Gear has a 7mm hole for shaft. Motor is a bit over an inch long and 3/4 inch wide. I have a motor and gear set up in a temporary test rig and I have trouble stopping the gear shaft from turning , using very tight finger pressure - appears to have very high torque. Even with medium finger pressure the shaft roes around 120 rpm.

Anybody else used these motors? I will have to actually build the hull and wheels before I can see if the motors will work as needed.

Any comments welcome.
Jeff

[derekwarner_decoy]

Hullo Jeff.....

You now have 3 post threads, however essentially all relating to your proposed Mary Ann paddler build

Your call, but I would be inclined to ask Moderator DamienG to link them all in one new thread called PS Mary Ann by Jeff

This just makes for easier reading for all, including you reading members responses......

PS......sorry I misunderstood side mirror 12V motors in lieu of side window winder motors .......Derek

[DamienG]

I'd hazard a guess It's for ease water evacuation from the blades. There bye saving on power needed.

[DamienG]

A few more details please Jeff dimensions of these motors and any idea of the RPM and if you apply 12v can you stall it with your fingers?

Damien.

[TailUK]

I'd hazard a guess It's for ease water evacuation from the blades. There bye saving on power needed.

Of course, that why waterwheels are solid sided to retain the water and use it's weight.  That said, a large proportion of side wheels are iron construction and solid versions would take some moving especially if they were lifting large amounts of water.

[jeff1949]

Hi Damien, the motors I have are 28 mm long and 20mm wide. They are 12 v, and while I can stall the motor with my fingers, it is VERY hard to stall the driven gear. Don't know what speed they free rev at, but would hazard a guess at around 3000 rpm. In my test rig, the driven gear rotates at somewhere between 120 and 140 rpm unloaded. Given the high torque I am hoping that they will drive the paddles at around the same speed.

Got the old broken mirror from the local tip recycle shop for 2 dollars - there are 2 motors/driven gears in each mirror. Different makes of mirrors may have different sized motors with different gear set-ups. I am going to get another mirror today and wreck it to see what I find.

Seems to me there could be a lot of applications for these strong little motor/gear set-ups, other than driving paddle wheels.

Thanks for the interest.

Jeff

[DamienG]

A 1:1 drive from worm pulley should be ok.

[derekwarner_decoy]

As Jeff says.......'a pic of the motor and drive wheel. 60 teeth on the gear, 10 on the worm'

So whilst there may be 10 teeth on a helical worm on the motor output shaft, essentially there is only one helical tooth in full engagement with the worm wheel at any time

From this, if the worm wheel has 60 helical teeth, the actual ratio is 60:1

This is naturally assumed that the worm on the motor shaft is a single start......if it were a double [x2] start the actual pitch is halved and the ratio can technically double ...or to 120:1

Hope this may clarify  and not confuse the basics .................. Derek 

[jeff1949]

Thanks Damien and Derek. I will try a 1:1 drive and see what sort of torque I get. Bought another 2 dollar mirror today - will dismantle this evening and see what the drive system is like, and let you know.

Jeff