Warship 18 had a pot bobber around the port screw, and its diver was laid up with a nasty naval disease. What you can't see in this pic is 18's bosun and engineering officer in a Zodiac, with a pair of navy-issue bolt croppers, snipping away at the stuff around the port shaft (and securing the Captain's dinner at the same time).
Took a lot of skill on the bridge of TF2 to get their bulbous bow just ahead of 18's shaft bracket, then apply the right revolutions to lift its stern gear clear of the water.