When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
There are a bunch of them, you can do a google search and find others.
This one that seems to have decent current and free data. Once the ship is out to sea it moves from land based tracking to GPS and most sites including this one charge for that...