That's crazy talk
It's a shame... That everything has to be considered a terrorist threat these days.
The Turtle was specifically designed to sink ships. This replica was modified to be less of a death-trap than the original was. It could easily be modified to achieve its mission in our time. This replica was aparently tested in carrying out a terrorist mission, without the explosives necessary to finish the job.
This little exercise was quite a bit more threatening that yelling "I have a bomb" in an airport. Threats like this must be taken deadly seriously.