Is there a site similar to orbitz or cheapoair.com except for boat trips instead of flights?

i’m planning on traveling around asia this summer, and i found that flight tickets are much much cheaper if i just book the flight to and from asia, and not all the flights in between (traveling from country to country). i figured it might be much cheaper to travel from country to country on boat once i’m already in asia— is there a place i can search boat fares on a multi city trip? similar to what orbitz does except for boat trips