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[kiwimodeller]

A friend recently acquired an old boat, supposedly built about 1950. Power is by what looks like a car wiper or heater motor with wound fields so it cannot be reversed easily although I guess the rectifier I use on my Taycols (thanks to Dodgy) would probably work on this too. It does however solve the problem by having a reversible prop with the change of direction driven by a worm and wheel which in turn was driven by a separate Basset Lowke motor and reduction box (photo attached I hope). We have replaced that with a more modern motor with built in 50:1 reduction which is working well but we need some advice on stopping the reversing motors in the correct positions - perhaps with limit switches? Any help appreciated and also it would be nice to know something about the Basset Lowke and the gearbox which does not have a name on it but does have "Model SW 4", Patented, and some numbers plus a sign like a Mercedes car three leg symbol. All help appreciated. Cheers, Ian.

[kiwimodeller]

Not sure what went wrong with my first post, the photo is fine but the text was all compressed so here we go again :-

A friend recently acquired an old boat, supposedly built about 1950. Power is by what looks like a car wiper or heater motor with wound fields so it cannot be reversed easily although I guess the rectifier I use on my Taycols (thanks to Dodgy) would probably work on this too. It does however solve the problem by having a reversible prop with the change of direction driven by a worm and wheel which in turn was driven by a separate Basset Lowke motor and reduction box (photo attached I hope). We have replaced that with a more modern motor with built in 50:1 reduction which is working well but we need some advice on stopping the reversing motors in the correct positions - perhaps with limit switches? Any help appreciated and also it would be nice to know something about the Basset Lowke and the gearbox which does not have a name on it but does have "Model SW 4", Patented, and some numbers plus a sign like a Mercedes car three leg symbol. All help appreciated. Cheers, Ian.


If you  PREVIEW it within 20 mins you will notice the font size is  2.

If you can change this number upwards, the size will increase. 

(it's a modern computer type thing  !!!!)

ken

[nivapilot]

 A friend recently acquired an old boat, supposedly built about 1950. Power is by what looks like a car wiper or heater motor with wound fields so it cannot be reversed easily although I guess the rectifier I use on my Taycols (thanks to Dodgy) would probably work on this too. It does however solve the problem by having a reversible prop with the change of direction driven by a worm and wheel which in turn was driven by a separate Basset Lowke motor and reduction box (photo attached I hope). We have replaced that with a more modern motor with built in 50:1 reduction which is working well but we need some advice on stopping the reversing motors in the correct positions - perhaps with limit switches? Any help appreciated and also it would be nice to know something about the Basset Lowke and the gearbox which does not have a name on it but does have "Model SW 4", Patented, and some numbers plus a sign like a Mercedes car three leg symbol. All help appreciated. Cheers, Ian.
 

[kiwimodeller]

Thanks for the help Ken, I have never previously gone back in to a post to make a correction and my computer is a hand cranked model so I was not aware of these modern tricks. Perhaps you could remove the second oversize copy of the post. Tomorrow I will get some photos of the mechanism for reversing the prop. Cheers, Ian.

[roycv]

The motor is a Basssett-lowke Marine motor 6 - 8 volts working.  Quite a powerful motor and worth about £25 upwards, depending on condition.  I have 2 with one in use in a Basil Harley Celia May.
A motor can be stopped quickly by arranging the off condition to put a dead short across the motor.
regards Roy

[kiwimodeller]

Shots of the main drive motor and the worm drive to change the prop pitch. The only problem we have is that the worm wheel can go full circle and back to full ahead. One suggestion was to take some teeth off the wheel but I think it would not re-engage. The worm drive motor is working off its own separate speed controller. Any ideas welcome. Cheers, Ian.

[kiwimodeller]

Thanks for that Roy, I am not sure what we will do with the motor yet, perhaps just have it for display of how things used to be. Do you recognize the gearbox? It seems to have another hole in the base to take a worm wheel for a secondary reduction. Also can you explain further about stopping the prop adjustment motor with a dead short? I would have thought that would damage the secondary speed controller? Thanks, Ian.

[roycv]

Hi Ian,  I overlooked the ESC on the reverse drive.  I was thinking a direct servo / micro switch system no speed control.
Could you not scrap the screw thread system and use a servo to operate the mechanism direct?  It might need a stronger servo but they are not expensive these days.  Seems simpler and more precise and sorts out the motor over run problem.
regards Roy

[kiwimodeller]

Roy, we would prefer to keep the prop setup as it is original. Also I think it might be difficult to get a servo to work direct as the actuation of the blade angle change is by one tube sliding within another and although it is quite big and clunky it does work well on the water. I was hoping someone might come up with some way of perhaps using micro switches to disconnect the power at the end of the travel in each direction while leaving the power feed live in the opposite direction. Not sure if I am making it very clear but I think we need electrical cut off at each end not mechanical. Willing to try anything! Cheers, Ian.

[malcolmfrary]

Its an old model railway thing - use a combination of switches and rectifiers.  The switches stop the travel when it gets there, the rectifiers allow it allow it to drive back.  I'm sure I saw a circuit posted on here a short while back, but can't just remember where.  Maybe a search of Inertia's posts?