Normally, NCIS is one of my favorite shows but if they start putting out episodes like this one with any frequency, I'm going to be forced to reconsider. This episode was a complete mess.
The whole Port-to-Port killer plot could have been very promising had it been made the least bit believable, but it didn't come close. To start with, though the killer presumably picks his victims with some care, as the episode begins we see him lure his victim into an alley using a technique he couldn't possibly know that the victim would fall for, in a place he couldn't possibly know that the victim would go, at a time he couldn't possibly know that the victim would be available. And since the victim was originally with another sailor (who offered to drive him back) even if it was somehow inevitable that he would pass by that alley, there is no way the killer would know that he was alone (unless, I suppose, the killer turns out to be the guy he went with to the bar). The only way it would make sense is if the killer were trying to randomly trap anyone walking by, but that contradicts everything revealed about the killer and this incident.
Later the killer arranges to be at the same bar as Tony and Ziva and surprises them by buying them drinks, delivered by the bartender. The drinks happen to contain body parts from the victim. So how exactly did the killer know that they would be going to a bar, and how did he transport his special ice-cubes there (obviously, there are ways to do it, if, he happens to know where they are going and has planned the bit with the drinks), and how did he get the cubes into the glasses since it was the bartender who prepared and delivered the drinks?
Then there is the red-herring suspect who happens to have been in every port the killer was in at the same time as the killer, but just happens to not be the killer as he just happens to have been under the surveillance of the CIA all that time. Perhaps by the time they resolve this they will have an explanation of a connection between the two men which makes this plausible but given the other plot-holes, I doubt that will happen.
As if the plot-holes involving the killer weren't bad enough, the script had the regular characters acting in ways which are not at all consistent with those characters. Gibbs' animosity and disrespect towards Barrett is rather unprecedented. Certainly, Gibbs has been established as someone who likes to run the show, and he does not tolerate incompetence well, but his actions towards Barrett were quite unprofessional, mean-spirited, and seemingly-petty. Ziva's reaction to learning Ray had not informed her of confidential information was mind-boggling and arbitrary, and did not seem to fit her character. Director Vance's actions were somewhat consistent with the last few episodes but, overall, his apparent animosity and distrust of Gibbs has never made that much sense.
While it is not a problem, per se, the character, Barrett, is rather annoying -- I hope they aren't proposing making her a regular.