Hi All,

If you have been reading my posts on the Comment Wall you are aware that I am building a fairly large R/C racing boat for autonomous offshore competition.

The R/C boat I have selected is the Zippkit VBox 2013 edition that is 46" long and 17" in beam. The boat is normally powered by a 26cc gas engine of around 5 - 7 hp, however I plan to use a brushless electric motor in place of the gas engine.

Since I do not need speeds of 50 - 60 mph for the kind of competition that I envision, I feel that a brushless electric motor of around 3 hp will be sufficient to drive the boat at around 25 - 30 mph. Therefore I have identified a Leopard 5692 1000kva 3000 watt 56 mm dia brushless motor as being a suitable candidate for my purposes.

I have decided on using twin 6S 10,000mahr LiPo batteries in parallel to power the motor. So now I am researching high current, water cooled ESCs with 180 - 220 amp capacity to control the motor.

After the propulsion and steering hardware have been installed in the hull, I plan to integrate a Pixhawk navigation controller and associated components into the hull to provide autonomous navigation.

I will begin the Project Discussion with the installation of the propulsion and steering hardware and then move on to the integration of the navigation controller platform.



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That's a beautiful boat Tom,

I used to race outboard single engine runabout class in a Switzercraft semi-hydro in the Intracostal Marathons and off shore.

I can tell by your design it is seriously designed for max speed and rides with very little of the hull in the water at speed.

Your biggest problem will be to keep it from lifting in the front and taking off, (I very nearly did exactly that once at about 60 miles per hour and went to beyond vertical before the transom caught and slapped it back down.)

And even though your boat is big for an RC boat it's small in comparison with real boats and the waves that launch it into the air are the same size.

That's a very interesting prop, not the cleavers I am familiar with, but looks like it's supposed to perform the same way.

I expect they don't allow controllable wings.

However if they do allow real time controllable trim tabs, you might be able to do some interesting tweaking while running.

In any case, should be exciting, please record video of it when you can, can't wait to see it in action.

Best Regards,


Hi Gary,

Thanks for the kudos, much appreciated.

Unfortunately the trim tabs are only manually adjustable:-(

The prop has around a 4 in pitch and is designed for semi-surface running as the prop shaft transom support (stinger) is adjustable in the vertical plane.

I have selected a motor/prop combination that will keep the max speed at around 30mph which is still really quite a respectable velocity:-)

The designer/manufacturer of the boat has given me a laundry list of recommendations about how to ballast and trim the hull to prevent front end lift. The boat is designed to ride on the back 12 inches of the hull. It is definitely a plaining hull:-)

I have ordered the two 6S 5000mahr 45C LiPo batteries I mentioned in my last post and they should be here by the end of the week. In the meantime I will wire up the ESC/battery cables so I will be ready to go when the batteries arrive. I have a setup where I can use a garden hose to provide cooling water to the motor and ESC water jackets.

I am presently building a navigation controller housing on the motor hatch cover to house a Pixhawk and associated components.



Hi All,

Well, the 6S 5000mahr HK LiPo batteries arrived on Thursday so I decided to make up a set of battery cables to go from each battery (port and starboard locations) to the parallel battery connection circuit board that is attached to the ESC battery input.

The wire on the HK battery says 10 AWG and is connected to a 4mm bullet connector plug. When I tried to build matching 4mm bullet connector plugs it turned out that my 10AWG cables were too big in diameter to allow the 4mm bullet connectors to lock into their respective housings.

Searching the internet I found that the Eflite EC5 battery/ESC connectors would handle up to 120 amps and are easy to engage and disengage. The local RC hobby shop had them in stock so I purchased two sets of male/female and individual male and individual female EC5 connectors. I will use the individual male connectors to build battery charging adapters for my LiPo battery charger. I have built two battery interconnection cables out of male EC5 connectors and 10AWG silicone cable that will connect the batteries to the parallel battery connection circuit board. 

In the meantime I had charged and discharged one of the HK LiPo batteries and found that all the cells were within 0.01v when the battery was full charged. I then charged and discharged the other LiPo battery and found that it followed suit with the first battery. Nothing like consistency:-)

I have attached a female EC5 battery connector to one of the LiPo batteries and will do the same with the second LiPo battery once it has been discharged to storage level.

As far as the navigation platform is concerned, the 3DR store is backordered on the Pixhawk and the PPM Encoder. However the GPS/Compass module and the individual 915MHz Telemetry Radios are available for purchase and I do have a spare APM2.6 on the shelf that I can substitute for the Pixhawk until it and the PPM Encoder become available.

ESC and Parallel Battery Circuit Board

HK 6S 5000mahr LiPo Battery

Battery to Parallel Battery Circuit Board Interconnect Cable



Hi Tom,

You're boat is coming along nicely.  Sure is a lot of work!  Great work on the finish.  Where do you plan to test it?


Hi Richard,

Thanks for the kudos, much appreciated.

Since this was my first attempt at building a wooden hull of this size, it has taken me much longer than someone with boat building experience.

Once the hull was together, I had to figure out a way to mount the brushless electric motor since the hull is designed for a 26cc Zenoah gas engine. Fortunately OSE had a nice motor mount for the Leopard motor that I was able to adapt the gas motor mounting rails. The ESC is mounted on top of the motor mount which is very convenient as far as the wiring and cooling lines go.

I have completed the support for the Parallel Battery Circuit Board Adapter so I can cut the battery to ESC interconnecting cables to length and attach the 8mm connectors to the Circuit Board Adapter end of the cables.

I have completed a hatch cover for the motor opening in the deck and have selected an airtight food container that is large enough to easily house the Pixhawk and its associated components.


Tom C AVD 

Awesome! Now where and when are you testing? Need a camera crew? I volunteer Irv. Lol.

Hi Richard,

I will do preliminary ballast and propulsion testing in my Association's mini lake and then may see about using the mini lake at Vista View.

I think that Irv is probably too busy with his Pixy/Mini Arduino project to help out at the moment:-)



Hi All,

Things have been at a standstill since I last posted.

I have been waiting on a Pixhawk, GPS/Compass, and other assorted components to be shipped from 3DR. I received a shipping notice on Friday that the products I had ordered had been shipped and that they will be delivered on Tuesday of this coming week. This will allow me to layout and assemble the navigation controller on the VBox hull starting on Tuesday afternoon.

In the meantime I would have put the VBox hull in the Association's mini lake and used just my R/C transmitter and receiver to test out its performance. Unfortunately my assistance, the wife, had to accompany her Mother back north for the summer and was not available to assist me in getting the hull in the water. She will be back in town this coming Wednesday so I might be able to test out the VBox hull with just the R/C radio this coming weekend.

All for now.



Lovely project. 

Do you know where can I get this plan to build that boat? probably a similar one can work too.... 

Awesome updates... keep going! 



Thanks for the kudos, much appreciated.

The VBox Crackerbox 2013 Edition comes as a kit and I doubt that you can try and build it from plans for cheaper than the basic kit cost Link 



Hi All,

The GPS/Compass Module, 915MHz Telemetry Radio, and some miscellaneous cables arrived on Monday and the Pixhawk and PPM Encoder arrived today.

On Monday I laid out the navigation controller plate and attached a vertical panel 2.5 inches tall to one side of the controller plate to mount the Spektrum AR7000 receiver, remote receiver and PPM Encoder. I then proceeded to mount the GPS/Compass pedestal near the rear of the controller plate to keep it as far from the Leopard brushless motor as possible and fabricated a mount for the Power Module and mounted it on the side of the controller plate opposite the receiver/encoder panel. A mount for the  915MHz Telemetry Radio was fabricated next to raise the radio about 3 inches above and close to the front end of the controller plate so that I could cut a hole in the front of the controller plate watertight cover to screw in the radio antenna.

Since I did not have the Pixhawk and PPM Encoder yet, I employed a spare APM2.6, loaded with ArduRover v2.46, that I had on the shelf to test the GPS/Compass Module, Telemetry Radio, and Power Module. While attached to my PC with the USB cable I used MP to verify that the GPS/Compass Module were functional. I then attached a  915MHz Telemetry Radio ground station to the PC and powered the APM by battery through the PM and verified that the 915MHz Telemetry Radio was functional. So far so good.

Today, after receiving the Pixhawk and PPM Encoder, I attached the  Spektrum AR7000 receiver, remote receiver and PPM Encoder to the vertical panel and fabricated a small sub plate to mount the Pixhawk on the navigation controller plate. I then connected all of the components together and proceed to load ArduRover v2.49 onto the Pixhawk.

Navigation Controller Top View

Navigation Controller Front View

As can be seen in the picture above, I still have to mount the speaker and the arming switch on the controller chassis.

At first MP had trouble trying to connect to the Pixhawk to load the firmware so I used the FMU reset button instead of removing the power to the Pixhawk to reboot the Pixhawk and that did the trick. The Pixhawk appeared to function correctly and the GPS/Compass Module was observed to be working correctly also. I then calibrated the R/C transmitter using the MP Radio Calibration screen.

The final step was to power the Pixhawk with the battery to be able to calibrate the Compass and to check the functionality of the 915MHz Telemetry Radio. Upon powering up the MP made connection with the Pixhawk through the Telemetry Radio so I proceeded to calibrate the Compass and setup the Mode Control for Manual, Learning, and Auto. I still have to conduct an accelerometer calibration to complete the setup of the navigation controller.

My assistant, the wife, will be back tomorrow with the family camera so I will have her take a few pictures of the layout of the navigation controller and where it will mount on the VBox deck.

Navigation Controller Deck Plate

Navigation Controller with Water Resistant Enclosure



That is an extremely impressive build Tom.  I can't wait to see a video of it in action.

One note - the 3DR Power Module only goes up to 18v i.e. 4S so you won't be able to use it in your 6S setup.  However HobbyKing do sell a 10S one which ardupilot supports.


Another option is the AttoPilot module


See the wiki page for info


Note that our CanberraUAV team has purchased some HK ones to use in our TradHeli that we are testing with for the next OBC in 2016.

Further, if you had 2 power modules I think we can connect both to the pixhawk and monitor each battery separately.  A quick look at the parameters tells me the code can do a second power module however I can't see any info on how to wire it up.  I've never done it myself but I'll see if I can put some info together on the wiki on how to do this.

Thanks, Grant.


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