Seawolf Park

Seawolf Park is on Pelican Island, across from Galveston. It is known for hosting USS Stewart, a destroyer escort and USS Cavalla, a submarine. From the end of the park, you can see SS Selma, a sunken concrete ship (not a ship that carried concrete, a ship made from concrete.) 

As it is near the end of Galveston Island, you have a very good view of the cruise ships sailing out of port every weekend about 5pm - as long as it's not freezing.