JR Marine Liner + JR Pass

I noticed there are so called liner trains where the JR Rail Pass is not useable. From Okayama to Takamatsu there is this JR Marine Liner. I am not sure if this is considered a "liner" or not. I know most liners are bound for suburbs mostly. Is there any list or so for liner trains where the JR Pass is not useable?

Although the "Marine Liner" has "Liner" in its name, it is a regular rapid train and not one of those suburban "liner" trains. In other words: yes, you can use it with the Japan Rail Pass.

I noticed there are so called liner trains where the JR Rail Pass is not useable.

A Japan Rail Pass is useable on JR liners, but if the liner requires a charge, you need to pay for it.
JR Marine Liner does not require a charge, so you can use your Japan Rail Pass.

Some JR urban liners are offered so that commuters can have seats, and requiring a charge at 500 yen or so per ride.

I've ridden that train on a JR pass more than once while staying in Okayama. Its a lovely trip across the Seto Ohashi bridge. Ritsurin Koen is fantastic http://www.japan-guide.com/e/e5401.html Just make sure you get on the right bus. First time I didnt & ended up at a Mall. Did some good shopping though :)