Does anyone know of night ferrys that run from October 13- October 16?
From where? Athens? Here are all the ferries from Athens (Piraeus) to Santorini in October:
https://www.gtp.gr/RoutesResults.asp?SchDay=0&SchMonth=10&SchYear=2016&CompanyId=0,2&SortType=1,2&AroundDate=0&Origin=EGR1AA10ATHATC,75,8&Destination=EGRSKY22,3125,6&MoreResults=1&Intern=0&FOrigId=&FDestId=&FOrigId1=&FDestId1=&StartFrom=1
If you mean from Rhodes, Kos, Karpathos or some other island linked to Santorini by ferry, click on "new search".
Night ferries to Santorini offer awkward arrival times and hotel check-in doesn't normally accomodate early arrivals, so be aware that you might have to kill some serious time before anyone shows up to even let you drop off your luggage while you wait for your room to be available. The only "true" night ferry is the Prevelis, which leaves Piraeus at 9:00pm, arriving at Santorini around 06:00am, but only on Tuesdays. The others arrive between Midnight and 03:00am.