User blog comment:Lord Loss/Monster Appreciation Week: Hallowed Jhen Mohran/@comment-6050823-20130818222957/@comment-6050823-20130819012559

I found some more info.

The reason why they use the ship against Jhen is not just because, of its hulking size but, because the sand in the Great Desert is mostly quicksand and, hunters and the crew can potential be sucked into it so, thats why they have rope attached to them and have some hanging from the back of the ship.

It turns Jhen Mohran are quite docile but, will turn aggresive when they need to, especially towards the Dragonships, since they see them as potential rivals.