rmk ....... the seat scramble is for the Basic Economy fare.... for just about €4-5 more, you can get the "Reserved Economy" seats -- sometimes called "Aircraft Seats" (I don't like to call them that, because it makes one think of the cramped & Crowded "cattle car" seats aboard modern planes. The "reserved economy seats" are padded, leanback, ample legroom, footrests, & VERY comfy, by contrast). This is a numbered reserved seat indoors. With this fare, you are welcome to sit outside on deck as long as you like, wherever u find a seat. However, when you want to come inside to read or snooze or snack (the seats hve a good folddown tray), you have a seat waiting. I highly advise this if you are on a longer journey ... 3-5 hours.
Economy-reserve seat TIP #1 -- at agency, ask for seats in a SIDE compartment.,.. these are smaller areas, quieter. The central area is huge, like a movie theatre, and brightly lit. TIP #2 -- if it's afull ferry, sometimes when u come indoors, you'll find a "Squatter" in your seat... just show your ticket & they'll move. TIP #3 -- if the "squatter" is an older Greek lady in a black dress with lots of parcels, do NOT confront her! Find a ferry steward to do the job.