Over the last few months, I have been busy building a fully autonomous sailboat that attempted to cross the Atlantic Ocean.
It was initially launched from Newfoundland heading towards Ireland. Although the initial attempt was not successful, I've gained a lot of extremely valuable experience, and I am going to build another, more capable boat. You can find more details along with a tracking map on www.opentransat.com.
The base consists of a surfboard and aluminum profiles. It is balanced by a heavy keel with lead weights that would flip the boat back over in case it flips. All materials used should survive for years in the ocean. It is rather an experimental concept that can be easily modified to test various configurations. My next boat will be optimized for speed.
The primary power source is four LiFePo4 3.2V 36Ah cells that are being charged by a 100W solar panel. When the batteries are fully charged, the boat can work four days without any sunlight.
The boat reports its position via the Iridium satellite network using the RockBlock module and two additional SPOT trackers (Globalstar satellite network).
The main electronic components are sealed in a Pelican case. The Iridium satellite module, as well as GPS, are in a separate polycarbonate case for better signal reception.
There are plenty of sensors on board that tell us more about the condition of the boat, such as the humidity inside the waterproof housing, air temperature and water temperature. There is also a hacked action camera that is powered by the main source, and it is turned on by the Arduino controller for 30 seconds every hour. The video is recorded on a 128 GB uSD card.
Hopefully, I will recover the boat one day to see exactly what went wrong before proceeding to the next design. My next attempt will be most likely next year, but it depends mostly on the weather conditions (it's not a good idea to navigate the boat through icebergs or hurricanes). Crossing the Atlantic Ocean autonomously is quite a significant challenge. At the time of writing this post, nobody so far has ever attained this. I will keep you updated on this front!
The MicroTransat Challenge competition with the rules that my boat strictly follows is below:
Project website:
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Comments
@Global Innovator
I still believe it wasn't the outer structure that failed. As seen in the comments in the tracking map, the software had some issues and the hardware watchdog timer was trying to reset the boat every three minutes with no success. The watchdog timer monitors the main software loop, however, nothing monitors the watchdog timer :) Both software and hardware have to be radically improved in my next design.
Then the secondary (red) tracker failed. It seems that the batteries powering the red tracker were not being recharged. The small solar panels could break when the boat hit a rocky shore or maybe some floating object hit the solar panels during a storm.
About the yellow tracker failure: just before it stopped reporting, it reported a low battery state and this happened after a storm. One explanation is that internal wire connections between multiple battery packs broke.
The compass failed after another crazy storm. It's in the same waterproof case as GPS and RockBlock. Both GPS and RockBlock were working.
This series of events makes me believe that all problems with the boat were actually inside the cases, i.e. the hardware I made is not shockproof enough to survive a storm in the North Atlantic. I can imagine the boat "flying" a few meters above the surface and then falling back on the water. It would be awesome if I had a chance to recover the boat one day and see what happened.
The boat survived some brutal testing like falling on a concrete floor, jumping on the solar panel and submerging the sealed polycarbonate cases at a 30-meter depth.
The solar panel is semi-flexible.
The side floats improve stability like a trimaran.
As I explained a few posts ago, I am focusing on sailboats at this time, but I would love to see your fleet of motorboats! Controlling a boat with two thrusters is less effective than using a rudder, but you can do it indeed. If it is going to make the boat more robust, it's more important than the effectivity. I think you need some feedback from the motors to control RPM. After weeks or months in the ocean, the motors may run at slightly different speeds even if you set the same PWM, but maybe a proper PID algorithm combined with a gyro feedback will do the job.
Andy,
Thank you for your reply.You have designed your boat as open double-decker.
Open double-decker boat is ok for tests on the lake and not fit to fight wild ocean waves and storms.
Solar panel is not firmly attached to the surfboard via Alu frame.
There are 3 or 4 sealed cases, directly exposed to ocean waves, the same for wiring.
I would like to design for you single-decker Solar Sea Charger and test semi-flexible solar panels.
Boat crash tests can be done on the lake, locally to keep budget low (no need for sat modem).
If tests run ok, I would like to design and build 10 Solar Sea Chargers for remote testing by third parties,
if there is any interest.
Alu profiles made frame is exposed to stress if built as an open decker, so Alu framed glass-based solar panel can brake easily.
I am not sure what is a role of side floats in light blue.
They don't provide protection to cases with electronics against lateral ocean waves.
I have 2 electric thrusters, so the surfboard can be controlled by 2 motors and there is no need for the rudder.
I like the option to have hull replaced by the surfboard
Please let me know your opinion.
@Gary McCray
Good point, I will try to optimize the sailwing for both thrust and robustness. There must be some specific curvature that is most effective.
@Global Innovator
Yes, the solar panel is partially shaded, but from what we see on the tracking map, it still worked well - the batteries were always fully charged. In my next design, I want to improve this issue. I will use multiple solar panels connected in parallel using Schottky diodes, so they can deliver different current. It will also make the design more robust - if one solar panel fails, no problem. I have to point out that it is very hard to estimate the actual solar power that's delivered, because there are so many factors that affect the performance - the waves, the average slope, weather conditions, etc. I would rather calculate the worst case scenario (a few days without sunlight) and add more solar power than necessary. It can be optimized later.
Yes, the boat seems to be lost. I am building another boat with a very similar hardware as presented in this article, but improved in several aspects. It will be all custom made (no modules and no connections through pins), but the basic concept will be the same. I will keep you updated on my next boat.
@Adam Kilpatrick My plan was to attach a heatsink to the Pelican case, but I saw during testing that it's not necessary in the cold waters of the Atlantic.
Andy,
my congratulations on your project.
Let me join you (your team).
I am really sorry to learn from Facebook
https://web.facebook.com/OpenTransat#
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OpenTransat
The bad news and the good news
The boat hasn't reported its position for the last 19 days. While it is still possible that one of the trackers will wake up, the boat is now lost in the ocean with little hopes of recovery.
"
It was exactly my first question to you.
If lost automous boat can be tracked and recovered in some way (failsafe algorithm).
I have contacted Liquid Robotics since there is already another design of wave glider in operation by humans on lakes to work as a rigid structure.
Seacharger is another excellent project.
There is one problem if you install solar panel horizontally and have sail mounted to shade the solar cells from time to time.
Poli-mono solar panels should be operated shading-free since output voltage is almost constant (within range) but current of individual solar cell can fluctuate from 8A to 0.8A affecting power output to drop from 100W to 10W at full insolation level.
Basing on astro data, shading of solar panel (shading of individual cells) by the sail can be easily calculated and plotted to give you deeper insight into the problem.
Is it really true your boat is lost since your original entry is one day old and your Facebook entry is 12hrs old only
https://web.facebook.com/OpenTransat#
@Andy Osusky
nice work!
I wonder if you could use sea water to help cool your electronics box(es)? Wouldn't necessarily have to involve piping running into or out of the box itself, might work just by running a panel over the outside(underneath) the box. Could also be fairly passive and simple, just a small pump running of a small seperate solar panel; it will then only run in daylight hours when overheating the box is an issue.
Mostly you are right, the sea is very big and the likelhood of running into or being run in to is very very small and probably an inconspicuous profile is less likely to attract unwanted attention.
Good point about the high reflectivity white paint to reflect the sun.
I'm sure the high contrast lettering would be sufficient.
Maybe the wording should read something like "Robot Boat Stay Away" - "Plague" would have done it in the old days.
AIS would certainly seem like it would work for the larger vessels and the smaller ones are more likely to see you anyway.
My thought regarding the triangular versus rectangular sail wing was that the potential torque applied to the sail / mast during a wave or roll over event would be much lower, making it considerably more likely to survive.
The surface of the sail is still shaped like a wing (an airfoil), just with a continuously decreasing chord (there are some military planes that use this shape of wing referred to as a delta wing.)
And at the low speeds of a sail boat the deleterious wing tip turbulence generated by this design on an airplane is not an issue.
@Ben
I was testing this boat on a lake, but I am going to test my next boat in my favorite place - Canary Islands. That's where I started a part of the development. The conditions there are very close to the real ocean conditions - high winds and rough waves.
@Gary McCray Now I understand, it's like a water scooter.
The sailwing will have an inner structure like an airplane wing. The mast will be made from a thick carbon fiber tube.
Regarding the color, yes, it is one of the recommendations on the Microtransat Challenge website. However, too much of attention-catching stuff is a double-edged sword. There is one team whose boat has been caught by a fishing boat for the third year in a row. The captain was just curious and pulled their boat out of the water. Then he called them to pick up their boat at the harbour (usually, very far away). By the time the boat was caught, it was doing well.
I am going to implement AIS to avoid other vessels.
I am thinking out loud - does it make any sense to be visible to the vessels from a large distance? The autonomous boat length is limited, so it doesn't impose any hazard to the ships that are in the ocean. I don't think a big vessel will change its course just to save my relatively cheap toy ("look, someone has lost his model boat"). They will run into it whether they see it or not and they won't even notice. When we threw the boat overboard, it was lost from sight in a minute.
Because the electronics will be sealed inside the hull (and some sensors will be inside the sailwing), I need to make it as reflective as possible. Otherwise, the electronics will overheat during intense sunlight. That's why I want to paint it white, but there will be high-contrast letters on the sailwing.
Congrats for this interesting project ! Did you consider trying first on a smaller distance than the ocean ? For example something like the Channel (between UK and France), that's a few tens of kilometers and that a lot of people have crossed to break different records (swimming, human powered plane, etc). Of course it's a less exciting challenge but for example doing zig-zags in a similar area until reaching an interesting distance would allow to test your system in real conditions without getting too far from the coast(s). Notice that the Channel is probably not a good place to start as it's crowded by boats of all sizes (and even by a train...)
Hi Andy,
The submarine thruster props I was talking about are actually long spirals more like an Archimedes screw than a conventional prop.
They are actually primarily made that way so that they do not reflect Sonar in an easily recognizable pulsing pattern and so that they have a minimum acoustic signature of their own.
But in reality, they are also non-fouling and typically just go through stuff that would immediately foul normal propellers.
I believe some small electric trolling motors have similar props available specifically for their anti-fouling characteristics.
I do think the rigid sailwing is an excellent alternative to a conventional sail.
Of course the trick there is to make it's structure and especially it's internal spar (and hull pivot) strong enough to withstand being bashed around by storm waves.
Most sailwings I have seen are rectangular things that stick way up into the air.
I suspect a lower profile could be easier to ruggedize against potential storm forces.
I have seen one design that had three or four sailwings in a line that were ganged together that seemed like it might provide a more secure structure.
Also you can make a sailwing in a triangular design just as effectively as a rectangular one, it would just have a decreasing chord, and that should make fouling less likely.
As far as vessels at sea, you probably do need to make some attempt to be visible so ships / boats could spot you more easily.
Seems to me painting everything in reflective International orange would give you the best visibility.
And maybe a couple small optical/radar retro reflectors on deck or the top of the sailwing.
Just a few thoughts.
I watched a video of a very large ocean research vessel going through continuous waves that were higher than the top of the bridge (over 80 feet).
Eventually smashed in the glass on the bridge, nobody was hurt and they got home, but the power of the sea in a storm can be awe inspiring, I really love the idea of these little things bouncing around in that and then just keeping on trucking.
Best,
Gary
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