Up-to-date info seems scarse, but the '
itsliverpool.com ' site says
"The Liverpool on the Waterfront programme, which is free to the public, runs from late May to early June.
The programme will be launched with the city hosting the 70th and final national anniversary commemoration of the Battle of Atlantic on May 24. It will close with the revival of the Mersey River Festival on June 7-9."
I've just found a better link from them
here (click). This says 11am to 5pm, and lists many of the ships.
Hope this helps. I've got friends going over there this afternoon...