Hey everyone. A while back I integrated a pixhawk into a RC sailboat. I was surprised that it actually made all the waypoints without too much struggle.
Since Edgar won't launch until later this spring, I figured outfitting the sailboat with a pixhawk, etc. and Sailing it to Hawaii would be a good winter challenge.
The boat is small, 42" length with a small cockpit that will carry all the electronics/battery and house the rudder servo.
Waypoints will be entered in before the mission starts. Keeping an eye on the wind patterns, I can adjust course of "Aidan" via satellite to sail correctly in the wind The sail will be limited to 30 degrees of travel in either direction. Getting sails made, even for RC boats are expensive. So, I got a sewing machine, 9oz Dacron sail cloth and sewed my own. Below is the first test sail. It is similar to a storm sail for this size of boat. Hopefully sail 2.0 will be much more robust, lol.
You can see the relative position of the electronics. The servo is attached to the underside of the cockpit cowl. I am leaning toward fully potting (submerse all electronics in potting compound) so that addresses water issues. Waterproof cases I have found have too much bulk and weight for the working space they provide. The servo is a waterproof servo.
The power system is solar powered. I have managed to fit three panels that will give an output of 18 watts at 5v. This array will be able to supply up to 3 Amps at 5v in full sunlight. The battery is 28AH which will allow the electronics 35 hours of working time before the battery shuts down in the absence of sun. If the battery were to hibernate, it would come back online and restart the kit once it starts to recharge and hits a certain value.
Aidan will be sending telemetry on the voyage. This will include position, battery power, water temp, air temp and probably AIS information.
The Keel is 90 degrees to the hull. Ideally I want a swept back keel so seaweed, mermaids and Krakens will slide off. I am looking at adapting another keel for this, or I might sail it as is.
I am also working on addressing some issues with the rudder assembly for this trip. First up, waterproof servo. Next, replace the plastic bushing with bronze. The tiller is plastic as well and I am looking into to having one CNC'd in titanium. The rudder is plastic as well, but it is sturdy enough. One issue that concerns me is that the servo rods are exposed above deck. Everything I thought of to address the issue of exposed rods struck me as over-engineering the problem, so I will most likely get a thicker gauge rod and leave it at that.
I am shooting for a March\April launch, once El-Nino has had his run and things calm down a bit out here.
I will update the progress here, and also will be updating my twitter feed.
Replies
Its a Laser!! The stock keel could give you problems.
Regards,
David R. Boulanger
Yeah, i think so too. I have looked at other keels and hoping I can use a Soling 1 meter or v32 keel. Not sure how that would affect the balance though.
I don't know off hand what a Laser keel weighs. A typical Soling 1M keel is 7 pounds but only half or a third even the draft of the Laser.
What are you using for a wind vane to tell the boat how much to sheet in the sail?
I have an EC 12 that I have thought about converting to being autonomous.
Regards,
David R. Boulanger
I will probably buy two keels from other boats and give them a try.
No wind vane. On such a small boat as this, there is no way a vane could be expected to survive and still be accurate. So, the sail will be sheeted to travel 30 degrees to port\starboard. I will track wind via sites like this, https://www.windyty.com and upload waypoints to the pixhawk to adjust course as needed.