Solo sail -1

September 6, 2018 2:46 PM

Unmanned sailboat successfully crossed the Atlantic. A battery-powered glider did it in 2009, and gliders are busy with research. No completely autonomous sailboat has made it across yet, but the 2018 contest is underway -- and there might be a winner.
posted by clew (12 comments total)

As someone who's done a fair amount of sailing and an excessive amount of computer science, I'm going to go ahead and guess that the primary reason why no completely autonomous sailboat has made it across previously is that nobody has found any good reason whatsoever to spend a lot of money and time building an autonomous sailboat capable of crossing an ocean.
posted by sfenders at 3:51 PM on September 6, 2018 [9 favorites]

And yet so many people have spent so much time and money building autonomous sailboats that didn't actually make it to the starting line.
posted by clew at 3:54 PM on September 6, 2018

On reading some more of TFAs I see that it's also that the main reason for trying, aiming to win the Microtransat, is complicated by very tight size restrictions.
posted by sfenders at 3:57 PM on September 6, 2018

> Year: 2014
> Boat Name: Aboat Time
> Tracked Time: 5 days, 11 hours
> End Result: Caught in a fishing net.

> Year: 2015
> Boat Name: Aboat Time
> Tracked Time: 9 days, 9 hours
> End Result: Picked up by a fishing boat after running aground.

> Year: 2016
> Boat Name: Aboat Time
> Tracked Time: 6 days, 1 hour
> End Result: Caught by a fishing boat on July 13th.

> Year: 2017
> Boat Name: Aboat Time
> Tracked Time: 2 days, 18 hours
> End Result: Caught by a fishing boat on July 25th.
posted by sfenders at 4:08 PM on September 6, 2018 [6 favorites]

Stupid fish.
posted by clavdivs at 9:00 PM on September 6, 2018

Yummy autonomous sailboat salad sammich
posted by not_on_display at 11:21 PM on September 6, 2018

From the autonomous sailboat link:

The sloop rig's hull is made of Kevlar-carbon hybrid cloth, and is filled with 120 D batteries that power a GPS sensor, compass and wind vane.

120 D batteries sounds… wrong. Consulting the SeaLeon’s entry page:

Power source: 19x Eagle Picher PT 2300 Keeper II D size Lithium Thionyl 3.6 V 19 Ah Batteries. Arranged to give a system voltage of 14.4 V and a total capacity of 361 Ah.

19 D sized batteries.
posted by zamboni at 4:01 AM on September 7, 2018 [1 favorite]

(A "D battery" is the size. D gives only dimensions, not chemistry or terminal voltage. xR20 == D, where x gives the chemistry/system.)
posted by introp at 9:14 AM on September 7, 2018 [1 favorite]

How do they get 14.4 v (needing groups of 4 in series) with 19 of them?
posted by grahamparks at 10:13 AM on September 7, 2018

Regardless of the size thing, how did 19 batteries become 120?
posted by Dysk at 10:47 AM on September 7, 2018

Well, when a mommy battery and a daddy battery love each other very very much...
posted by Greg_Ace at 11:50 AM on September 7, 2018 [1 favorite]

To get 14.4V and 361Ah it's actually a 19 parallel, 4 series stack. Which is still only 76 batteries...
posted by TheJoven at 1:05 PM on September 7, 2018 [1 favorite]