VVCA "Shame to see the Endurance go though although why the RN has any sort of Droggy role whatsoever always beats me."
Knowledge is power. Despite the wonders of satellite imagery, you can't look under the water very far, and the greatest threat to any vessel, on the surface or submerged, comes from a submarine. The droggies don't just swing a lead, they measure water temp. all the way down to the sea bed, and as a rotary boy you must know that sonar is affected changes in temp of the water. If you know where the layers are likely to be you can use (and probably hide) your assets more effectively.
And that's just one reason - there are more, but I'd have to kill you as soon as I told you
