I ran a line boat mooring the ships at Mobil in Beaumont back in the 70s. Like you said, the supertankers cannot come into port due to their draft, which in the Neches, is/was around 40 feet max. If my memory serves me, Galveston and New Orleans could handle the drafts (approx. 80’). We actually had the Manhatten visit our grain terminal in Beaumont. She was 1000’ long with a helicopter pad and an ice breaker bow. She only received a partial load and topped off in NO. Coming up the Neches to port, all ship traffic was halted for her to pass, same when she sailed. She also had some history that I won’t get into.
The supertankers would stay in deep water and off load to the shuttle tankers which would pick up their pilot and tug, navigate up river (about a 2 hour trek) to Mobil docks in Beaumont, where I would run their mooring lines to the pilings. Mobil employees handled the dock mooring. I also had to release the lines for the ships to sail. We also handled stores. Those were good times. Sorry for the memory post.