I find this hard to believe even if autonomous ships can be done without a bridge. The Emma Maersk has 15,000 TEU and a crew of 13 http://www.emma-maersk.com/specification/
The Maersk triple E's have a crew of 13 and consume ~136 tonnes/day of bunker fuel[2] which costs currently ~$315/tonne[3], for a daily fuel cost of $42,840. So right off the bat that number is very suspect. Even for other ships like the CSCL Globe with a crew of 31, that's a 12x difference.
I don't understand how that estimate can possibly be true. Ship captains and engineers make ~80k annual and crewmen make under 40k. For a crew of 20-30, $3,299 would be basically bang on for a daily crew cost but there's no fucking way fuel and depreciation only cost $4,200 a day. Even a 4000 TEU ship (tiny) at 17 knots (snail) burns $15,000+ a day.[4]
[1] https://www.bloomberg.com/news/articles/2014-02-25/rolls-roy...
[2] http://www.scdigest.com/ontarget/13-09-12-1.php?cid=7401
[3] http://www.tsacarriers.org/calc_bunker.html
[4] https://people.hofstra.edu/geotrans/eng/ch8en/conc8en/fuel_c...
I know a lot of ships spend days waiting to enter the panama canal, or days in port. Crew is certainly paid for those days as well. What percentage of the time is the ship fully underway and using fuel?
That 44% figure might be more reasonable if you're only burning fuel 1/3 of the time.
The stretches to explain that gap would be ludicrous eg 3 shifts, each costing the company 3x more than their actual salary, and the engine being turned off 70% of the time. Even still that requires you to disregard depreciation, which for the triple E is at least $17,000 a day.
Canals, port clearances (bridges, channel depth, width), dockside facilities, etc.., all put limits on ship sizes. There is a whole slew of "max" and other classifications: Panamax, Suezmax, Chinamax, Seawaymax, etc. "Handysize" is still my favourite of the lot.
https://en.m.wikipedia.org/wiki/Cargo_ship#Size_categories
For small and local transit, think the US Great Lakes, the Baltic Sea, English Channel, Mediterranean, South Pacific islands (many small populations and ports), and coastal transit along Africa, South America, and Asia, outside the major ports, there's still call for many much smaller ships.
As with other areas, automating smaller instances may be where the payoffs come as the relative labour costs are greater relative to total operating costs. Part of that comes from simple logistics:
* You need multiple shifts. * You need a helmsman, and an engineer, for each shift. * You need a cook, and other housekeeping.
That's already a crew of about 9 - 12.
Regardless of whether your DWT is 20k tonnes or 400k tonnes, your staffing actually doesn't change all that much, and may well increase as smaller ships frequently have (and I presume staff) their own offloading equipment.
I could believe human labor being 44% of the cost of operating a ship, but the cost of operating a ship is also next to nothing. It's the last mile that engulfs these costs. Economically speaking it may not make a lot of sense to make ships autonomous.
But making ships autonomous is probably a lot easier than cars or airplanes, and could probably considered low-hanging fruit in the tech world. You don't need fancy computer vision algorithms to deal with a ship; GPS alone will probably do. Ships don't get within several hundred meters or even kilometers of each other.