Archive for the ‘Hackerboat’ Category

Alex sanding the boat, early in the process.

Alex sanding the boat, early in the process.

Last weekend, Jeremy, Wim, Alex, and I got together to paint the Hackerboat. The original plan was to get it all done during daylight hours last Saturday... but the filling and sanding steps took much longer than anticipated, so we only got to primer. Just that made a major improvement in the boat's appearance ahead of MakerFaire next month.

The paint I bought for the job was Blue Water Mega Gloss topside paint. It's a single-part polyurethane marine paint. Since this iteration of the Hackerboat won't spend long periods in the water, we're going to do the whole thing with topside paint. It's not too horribly expensive -- about $18/qt. I want to paint the boat safety orange (so it can be seen easily), while Wim would like to paint it with dazzle camo. So we compromised on safety orange and black dazzle camo. I picked up one quart each of black, bright orange, and white primer.

The polyurethane paint is supposed to be very thoroughly mixed before use. Wim and I, in a bout of optimism, stirred both the primer and the orange paint. When the orange paint dried on the stir stick afterwards, we discovered that Blue Water's color department believes that ketchup is bright orange. I hope it will look more like orange over primer, but I am not all that hopeful.

The fiberglass work we did on the hatch coamings a couple of years back was pretty rough, so the first order of business was to get it filled and sanded. We went through about 3/4 of a gallon of Bondo getting the topsides in somewhat paintable shape. We probably could have used the rest of the gallon, but it was getting late and we wanted to get the primer on before the end of the day. There's not much description here because the tubes are full of tutorials on how to do this and it's not the world's most interesting work.

Bottom primed

Bottom primed

Once we'd gotten the last coat of Bondo on the boat, we immediately flipped it over to sand and prime the underside. This was nice and uneventful, and it made the bottom of the boat look less busted immediately.

The can of primer had led us to believe we'd be waiting a couple of hours before we could flip it over and finish sanding the Bondo. This turned out to be very pessimistic -- the first primer we laid down was dry to the touch by the time we were done priming the boat. We still waited half an hour (and time for a picture) before flipping the boat.

Wim and Alex priming the boat.

Wim and Alex priming the boat.

We masked off the hardware we couldn't remove and primed the topsides. It went on as quickly and painlessly as the primer on the bottom, and was mostly dry by the time we finished the coat. It took about 3/4 of a quart can to do the whole topsides. I think this is because we did not thin it; however, it is clear from that experience that we will have to thin the orange paint if we want to get two coats out of the can. We'll do the stripes in black over that as a third coat.

The boat looks better even with just the fill and primer; I am looking forward to finishing up the paint job today.

Filled and primed

Our launch last fall proved that the Hackerboat hardware was working fine (other than the GPS) but that the software needed a complete rewrite. We've been working on that for the last few minutes. Debugging is a bit on the slow side, but we anticipate being ready to get back in the water in the next couple of weeks. We will be at both MakerFaire Bay Area and Toorcamp with the Hackerboat in tow. This weekend, we're going to put some paint on the boat to it looks a bit better in preparation for the next launch and for public show. There will be pictures! But let's talk about the systems in preparation to talk about the software.

The current electronics configuration of the Hackerboat has a bit of a Rube Goldberg quality. The underlying intent is to build a system out of relatively small modules that can be added to without major hardware surgery. Here's a schematic diagram of the various bits and pieces. Dark red is power and power control, green is computers, yellow is propulsion, orange is communication, blue is sensors, and purple is non-propulsion actuators.


The first thing to notice is that we have two on-board computers -- a Beaglebone and an Arduino. The intent is that the the Arduino will handle all of the low-level real time functions while the Beaglebone handles all of the higher-level navigation, obstacle avoidance, and mission functions. Among other things, the relatively more power hungry Beaglebone can be put into a low-power sleep mode for extended periods, especially while in the open ocean. On the flip side, we can use the Linux environment and fast processor on the Beaglebone to support all manner of cool navigational modes and mission applications.

The communications is likewise a layer cake. Our ship to shore radio is a Ubiquiti 900 MHz Ethernet bridge. The shore side radio has a directional antenna built in to the radio and the ship side uses an external antenna on the mast. For internal data on the boat, we use a standard WiFi router. This means we don't have to futz with waterproof Ethernet cabling (expensive and troublesome)... and we can add new equipment to the boat for the cost of a WiFi interface.

Right now, the sensor fitout is very basic. We have an IMU/magnetometer combo for heading, a GPS for position, and start/stop buttons on the outside of the boat. We're planning to add cameras next, and of course we have the option to mount any sort of instruments we like for mission requirements later.

Next update will be painting, and after that I will get into our software architecture.

The Hackerboat Reborn

Posted by Pierce Nichols on 20 July 2014

A couple of months ago, we revived an old project, the Hackerboat. The original project was building a boat to circumnavigate the globe autonomously. This was, to put it mildly, rather a bigger thing than we could chew. So the revival is a bit more modest in scope -- we're building an autonomous boat capable of doing sonar surveys of dive sites in the Puget Sound. Once that's working, we'll go from there. Since Toorcamp was then a couple of months out, we made that our target. The boat was there, but not entirely functional. More on that later.

We chose solar-electric propulsion as the easiest to implement quickly. Truly long distance cruising will require something like sail or wave power, but that's immaterial to our more limited goals for operations within Puget Sound and in near coastal waters.

We bought an old kayak off Craigslist and set about modifying it. We made the following major modifications:

  • Added center, forward, and aft bulkheads
  • Added a keelson to allow us to bolt a keel and other equipment to the bottom of the boat
  • Added stringers under the deck along the rails between the forward and aft bulkheads for mounting solar panels etc
  • Built up the hatch comings to flat surfaces for simple hatches
  • Motor mount for a trolling motor
  • Geared, waterproof steering servo
  • Lead-acid batteries
  • A mounting frame for solar panels
  • A radio mast
  • Control electronics
Hackerboat under modification, showing the motor, radio mast, solar panels, and Jenny.

Hackerboat under modification, showing the motor, radio mast, solar panels, and Jenny.

The physical modifications ended up taking more time than planned, leaving the software and testing than would have been optimal. There was still significant amounts of electronics assembly, all the final integration work, and all but a tiny bit of the software to write when we left for Toorcamp with the boat in tow.

At Toorcamp, thanks to a tremendous amount of help from incidental volunteers, we were able to finish the electrical work, test the solar panels, test the low-level control electronics, test the motor, and add some status lights. We even got the radios up and working.

On Friday, we did a basic float test with an empty boat (no batteries, no solar panels). It floated well and we devised a system of ropes (thanks to Ratha and Trout) to make it easier to lift and carry the boat. There was no problem handling it in the low surf present that day. We also dropped the motor and connected the steering linkage in the waves. While not an ideal operation, we determined that this was a doable thing.

While we were able to get the low level control code up and running, we were not able to get the GPS navigation code or the shore station code running. With the end of Toorcamp fast approaching, we decided to launch anyways on Sunday and use the low level panic mode (run due east) to demonstrate the boat in action. We left off the keel, due to the difficult of beach launching with it in place. Neither of these turned out to be a great decision.

The lack of the keel is what truly doomed the attempt. We took the boat out into the surf, dropped the motor, and maneuvered it out to where Jenny was waiting for us. At that point, we had about ten minutes before the low level control system concluded that all was broken and it needed to run in to shore.

The  weight of the boat more that doubled with the addition of the solar panels and the batteries. We re-arranged the ropes so eight people could carry it, and took it down to the water. When we took it out into the water, we discovered two problems. First, the front hatch was askew. We fixed that. Second, the boat was listing to the right. We re-arranged the batteries (while chest-deep in the surf, naturally) to take care of some of the list. Not enough, as it turns out. As soon as Jenny took the boat under tow and we let it go, it rolled over. We grabbed it, turned it back over, and hauled it out onto the beach, done for the day.

Jenny preparing to take the Hackerboat under tow immediately prior to the capsize. Photo courtesy of Becki Brotman.

Jenny preparing to take the Hackerboat under tow immediately prior to the capsize. Photo courtesy of Becki Brotman.

Hackerboat on the shore after the roll-over. Note the GPS antenna on the bow. Photo courtesy of Zack Archer.

Hackerboat on the shore after the capsize. Note the GPS antenna on the bow. Photo courtesy of Zack Archer.


Installing the steering linkage in the surf. Photo courtesy Becki Brotman.


Recovering the Hackerboat post capsize

There was some water in the boat when we got it onto the beach, but not as much as I expected given that waves had broken over the askew hatch and we'd rolled it completely over. Nothing appeared to be broken, but the batteries were loose in their mounts and of course there was salt water on the outside of the electronics boxes.

Our current plan is to work to correct the mechanical, stability, and software deficiencies and get the boat back in the water at the end of August. We'll do it in far more protected waters this time.


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