[spockz]

Don’t many modern ships already have this? I recall watching “Big Ships” or some such on Discovery Channel about 15-20 years ago where they explained ships already having multiple stern and aft, starboard and port, “pods” either with jet streams or rotors.

[lambda_obrien]

Sure, but having driven ships with those, they're not as maneuverable as they could be. It takes time to deploy the pods and often they aren't available at high speed.