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Summary of Work done for Howard Johnson

16 August 2018

Howard is a long-time member and supporter of the Gauteng Model Boat Club. Alas, like many of us, he has boats gathering dust in the garage and needed help in making them seaworthy again. I gladly agreed to help and I am going to explain briefly what I did and why. 

Graupner Wiesel Torpedo Boat 

This was built decades ago by his son and has not seen action for decades too. This boat needed a new speed controller, and as it has two motors, the HobbyWing Quickrun 860 was ideal. The major problem was that both motors were using left-handed screw propellors, which meant that the torque of the motors turning in the same direction made the boat lean badly. Solution was to buy from overseas a set of left-and right-handed propellors. 
The RC was upated using the Hitec 27 MHz cheaply sold at Aerial Concepts. A bracket to hold two sets of 7.2 V 4600mAh NiCd was made. Also, the couplings were improved to run smoother and quieter.

 


Dumas PT-212 

This boat kit was bought by me from Aerial Concepts. I then got as far as adding the running gear and starting on the deck. I lost interest a bit and Bruce Tandy was keen to work on a torpedo boat that just needed the scale part done (the part I lose interest in). 
All it needed was the new RC installed and a new 2S Lipo battery to run for longer. I also added weights to the front so that the steering and stability was improved.

 


Graupner Weser Fire Boat 

This is a very old and classic kit. This boat required the most repair. Firstly, I removed all the old Mabuchi motors and their mounts and replaced them with three 550SH fan-cooled motors bought from RC Edge. I replaced the middle shaft as it was rusted in and repaired the Kardan couplings. Again, the boat required two left-hand and one right-hand propellors, three new motor mounts, and a water pump for the three water monitors. 
All these were bought from Cornwall Model Boats. A speed controller, HobbyWing Quickrun 860, was bought and a 6V 12 Ah lead acid battery. A peculiarity about this boat is that only the outer drive trains have rudders, and the middle rudder is not there. This means that the middle motor does not add to the steering and so I decided to put the middle motor on a microswitch to only turn on when the boat is going at speed. 
This means that the boat can run quite slowly and steer well. As the speed controller is a dual one, I used one of the motor connections to run the outer motors and the second motor connections to run via a microswitch mounted on a servo connecting to the middle motor (which I also gave a larger propeller than the outer ones). 
A second micro switch on a servo was used to turn on the Graupner water pump, being supplied by a 6V NiCd set. To run all this via the 6 channel radio, I also built a new servo tray. All batteries have an inline fuse. The most challenging bit was on the superstructure. The superstructure is removable, but also contains two fire monitors. 
This means I needed to redo the plumbing so that the water pump also supplied them yet did not make the superstructure unwieldly to remove. The best was to use silicon tubing and T-pieces from Midas for the window washers. A nice feature of the original build was to rotate one of the fire monitors and a search light. I had to rebuild that and also fix all the numerous leaks. I added about 3kg of lead weights to get it down to the water line.


 

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