Yup, boats with a draft of up to about 1.8m can use the port. The official I spoke to seemed a bit bemused by my question, but said just check in with port authorities on arrival. The phone number is 0884 707669.
More details on Vieste at: Adriatic links here: <A target="_blank" HREF=http://www.comoy.com/saillinks.html>http://www.comoy.com/saillinks.html