{"id":20404,"date":"2026-09-18T12:30:29","date_gmt":"2026-09-18T16:30:29","guid":{"rendered":"https:\/\/www.autonocion.com\/us\/?p=20404"},"modified":"2026-09-18T05:53:44","modified_gmt":"2026-09-18T09:53:44","slug":"4-foot-drone-boat-123-pounds-3100-miles-atlantic","status":"publish","type":"post","link":"https:\/\/www.autonocion.com\/us\/4-foot-drone-boat-123-pounds-3100-miles-atlantic\/","title":{"rendered":"A 4.26-foot drone boat that weighs 123.5 pounds sailed itself almost 3,100 miles across the Atlantic in 117 days on a 52.5-watt solar panel, carrying a thruster it was never allowed to use, and 37 boats have failed the same crossing"},"content":{"rendered":"

Every so often, someone crosses the Atlantic in a boat that’s way too small for the job, and it’s usually the same kind of story. It’s one stubborn person with a mountain of freeze-dried food and a satellite phone for when things go sideways.<\/p>\n

The latest tiny boat to make it across didn’t need either. Nobody was on it.<\/p>\n

It’s called PC13, and it’s a sailing drone built by Oshen, a company based in Plymouth (the one in England, not Massachusetts). On September 13, it reached the finish zone of the Microtransat Challenge, a long-running race for robot boats, after 117 days on the organizers’ clock. According to the Microtransat’s own announcement<\/a>, that provisionally makes PC13 the first boat to finish the east-to-west route, from the European side toward the Americas, and the first to finish in the autonomous division.<\/p>\n

So why does “autonomous” matter so much?<\/p>\n

The Microtransat has two divisions, and the difference between them basically comes down to whether anyone’s allowed to talk to the boat. In the unmanned division, a team can send its boat new waypoints or even steer it from shore. In the autonomous division, once the boat’s underway, nobody can send it an instruction that would point it somewhere else. It’s allowed to pick up public broadcasts, like weather forecasts and the position signals big ships put out, and that’s about it.<\/p>\n

That’s a pretty big difference, frankly. The only other boat that’s ever finished the Microtransat, a Norwegian Sailbuoy called SB Met, went the opposite direction, from Newfoundland to Ireland, in 79 days. It did that in the unmanned division.<\/p>\n

And the list of boats that didn’t make it is long. The organizers count 37 failed attempts. Going by the race’s history page<\/a>, the U.S. Naval Academy made six attempts, and every one of those tries ended with the robot hauled aboard a fishing boat. One of them was named Trawler Bait, which in hindsight was a bit on the nose.<\/p>\n

If the C-Star name rings a bell, we’ve written about these boats before, including a C-Star that sent back data from inside a Category 5 hurricane<\/a> and a pair that got launched off the back of a bigger drone boat near Plymouth<\/a>.<\/p>\n

So how small is PC13?<\/h2>\n

Oshen usually describes the C-Star as just under 4 feet long. PC13’s race entry<\/a> gets more specific. Its hull measures 4.26 feet, and it’s still under 5 feet long once you count the bits that stick out. The rules allow boats up to roughly 7.9 feet, antennas and all.<\/p>\n

It’s narrow, too. The beam, which is the boat’s width at its widest point, is about 15 inches. The draft, meaning how far it reaches below the waterline to the bottom of the keel, is about 23 inches. So PC13 goes deeper than it is wide, and the entry describes it as a single hull with a big keel for stability. That keel is basically a fin underneath that keeps the wind from shoving the boat sideways.<\/p>\n

The whole thing weighs 123.5 pounds as entered. That’s a little more than two 60-pound bags of concrete mix from the hardware store.<\/p>\n

\n
\n
Hull length<\/div>\n
4.26 ft<\/div>\n
About 51 inches. 4.83 ft overall. The rules cap boats at about 7.9 ft.<\/div>\n<\/div>\n
\n
Weight<\/div>\n
123.5 lb<\/div>\n
As listed on the race entry. Beam about 15 in, draft about 23 in.<\/div>\n<\/div>\n
\n
Solar panel<\/div>\n
52.5 W<\/div>\n
Feeds a 100-Ah battery. The entry doesn’t list its voltage.<\/div>\n<\/div>\n
\n
PROVISIONAL<\/div>\n
Race clock<\/div>\n
117 days<\/div>\n
May 19 to Sept. 13. The jury has a week from the finish to confirm it.<\/div>\n<\/div>\n<\/div>\n

The wind does all the pushing<\/h2>\n

PC13 raced in the sailing class, and the Microtransat rules<\/a> only allow wind power to move a boat in that class. Its entry describes the sail as a “wingsail in a dynarig configuration.” Basically, it’s a wing-shaped sail that turns as one piece, and instead of ropes pulling it in and out, a motor inside the hull swings the whole thing to the right angle for the wind. That’s pretty handy when there’s nobody on deck to trim a sail.<\/p>\n

Now, PC13 also carries a thruster at the stern, and its entry notes that the thruster went unused. There wasn’t much choice there. Using a motor to push the boat would’ve broken the sailing-class rules, so PC13 hauled it across the Atlantic without ever using it. It’s a bit like driving cross-country with a spare tire you’re not allowed to put on.<\/p>\n

So what’s the solar panel for?<\/h2>\n

Everything else on the boat runs on electricity, and there isn’t a lot of it to go around. The entry lists one 52.5-watt solar panel and a 100-amp-hour battery. In full sun, that panel makes about what an old incandescent light bulb used to burn through, and it has to keep the sail motor and the rudder motor turning, plus a small weather station, a sea temperature sensor in the keel, a satellite modem and the computer making all the decisions.<\/p>\n

The computer is an STM32, which is a microcontroller, the same family of chip a lot of hobby drone flight controllers run on. It reports home through Iridium’s short burst data service, which is basically texting by satellite. You get small packets of data rather than a live connection.<\/p>\n

So how much energy does that battery hold? I honestly can’t tell you. Amp-hours measure how much current a battery can deliver over time, and to get watt-hours, the same kind of energy number you see on an EV battery, you multiply by the voltage. If it’s a 12-volt battery, that’s 1,200 watt-hours. At 24 volts, it’d be twice as much. PC13’s entry doesn’t list the voltage.<\/p>\n

Which is a bit annoying, because the only other boat racing this year lists its battery in watt-hours. Brave Puffin, an entry from Boston that’s headed for the Canary Islands, lists a 100-watt solar panel and a 400-watt-hour battery. It runs on motors in the non-sailing class, and it’s in the unmanned division, so it isn’t really racing PC13. Still, it’s probably the boat to watch if you’re rooting for the home team, and the organizers’ tracker still had it at sea this week.<\/p>\n

So was it 117 days or 127?<\/h2>\n

You’ll probably see 127 days in a lot of the coverage. That’s Oshen’s number, and it counts from May 7, when the company says it launched PC13 from Gran Canaria.<\/p>\n

The race doesn’t work like that. In the autonomous division, a boat has to sail itself 40-plus nautical miles just to reach the official start line, and the race time runs from there. The organizers started PC13’s clock on May 19, and they say it covered a little under 3,100 miles in 117 days.<\/p>\n

For what it’s worth, May 7 to September 13 comes out to 129 days on my calendar, so I’m not totally sure how Oshen got to 127. Either way, the race figure works out to about 1 mph on average. You’d beat that walking to the mailbox.<\/p>\n

There’s no guy with a checkered flag out there, either. Each team picks a target point on the far side before it leaves, and the boat has to get within about 15.5 miles of it. If you plug PC13’s target coordinates into a map, you land in open water a bit over 200 miles east of Guadeloupe.<\/p>\n

It wasn’t exactly a smooth ride. Oshen says the boat went through a low-pressure system linked to Storm Dolly while it was still forming, around August 28 and 29. And according to the German sailing magazine Yacht, the rudder started acting up about halfway across, apparently from too much friction, and the control software adjusted for it on its own. If I’d written that code, I’d frankly be bragging about the rudder fix more than the finish.<\/p>\n

Oshen CEO and co-founder Anahita Laverack said in the company’s announcement that even near the end, “we weren’t certain that PC13 would reach the designated finishing zone.” It also took three tries to get here. According to Oshen, its first attempt ended after 20 days and about 6 miles, and a later boat sailed for 277 days and made it about three-quarters of the crossing before heavy seas took its sail.<\/p>\n

So PC13’s finish isn’t quite official yet. The Microtransat’s three-person jury still has to sign off, and the race rules give it a week from the finish to do that, which means a ruling is due by September 20.<\/p>\n","protected":false},"excerpt":{"rendered":"

Every so often, someone crosses the Atlantic in a boat that’s way too small for the job, and it’s usually … <\/p>\n

Read more<\/a><\/p>\n","protected":false},"author":8,"featured_media":20414,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[121],"tags":[],"class_list":["post-20404","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-industry","resize-featured-image"],"acf":[],"_links":{"self":[{"href":"https:\/\/www.autonocion.com\/us\/wp-json\/wp\/v2\/posts\/20404","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.autonocion.com\/us\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.autonocion.com\/us\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.autonocion.com\/us\/wp-json\/wp\/v2\/users\/8"}],"replies":[{"embeddable":true,"href":"https:\/\/www.autonocion.com\/us\/wp-json\/wp\/v2\/comments?post=20404"}],"version-history":[{"count":1,"href":"https:\/\/www.autonocion.com\/us\/wp-json\/wp\/v2\/posts\/20404\/revisions"}],"predecessor-version":[{"id":20417,"href":"https:\/\/www.autonocion.com\/us\/wp-json\/wp\/v2\/posts\/20404\/revisions\/20417"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.autonocion.com\/us\/wp-json\/wp\/v2\/media\/20414"}],"wp:attachment":[{"href":"https:\/\/www.autonocion.com\/us\/wp-json\/wp\/v2\/media?parent=20404"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.autonocion.com\/us\/wp-json\/wp\/v2\/categories?post=20404"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.autonocion.com\/us\/wp-json\/wp\/v2\/tags?post=20404"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}