This only covers container ships btw. For full coverage of all vessels, try the 'vessel presence' layer in Global Fishing Watch's interactive map, based on a feed from Spire: https://globalfishingwatch.org/map/
https://www.marinetraffic.com has most AIS transponders, I use it to track friends on commercial and private vessels.
https://aisvesseltracker.com/ is a good one too. Shows a LOT more, including cruise ships and pleasure craft.
It's also a bit limited. The gold standard is still kpler.
Thanks for the recommendation, looks interesting. I've used Vessel Finder due to something being a nuisance with Marine Traffic.