yes they did a crime. The crime was to plot and plan to introduce the drugs in the US. I guess that's where the boat was going to anyways. You do not have to commit a crime like actually killing somebody in order to be put in prison. Hiring the hitman or plotting to kill somebody will get you in prison as well and it is as criminal as it could get even if the poor guy did not die. That's just an example so I think it makes sense to say that they were planning to commit a crime in the USA and they were intercepted. That on top of the fact that the boat was not registered anywhere again is a crime to both US and International law, and that has been the case since the 14th-15th century with pirates
I am not an expert on the subject of course I would like to read somebody more related to the field and his point of view