Must admit I didn't particularly enjoy the last Dunker Drills I attended at Yeovilton.
I needed to be "in date" for night flying in the role as firefighting instructor on a mobile training team (Flag Officer Sea Training Staff) & that includes completing the helicopter escape drills. The course I was with seemed to comprise mostly of Middle Eastern Air Force helicopter pilots & aircrew, great blokes. No problem there you'd think- they'd all done it before & had been flown to UK to bring themselves up to date. They even had their oppos taking pictures of them as they surfaced.
I didn't understand the significance of the fact they were all wearing red bump-hats, the other two of us, both RN matelots, were wearing blue ones.
The problem? Not one of them could swim! They weren't the slightest bit bothered as they knew when they surfaced an aluminium grab pole with a loop at the end was lowered by the staff in front of them to safely recover them to the side of the tank as they smiled and posed for photos. (In a real helo ditch, they'd inflate their lifejacket AFTER they exited the aircraft, in case you wondered).
First drop, a six foot straight plunge, lights on, everyone exits in reverse order of boarding the "helo" through 4 different windows. No snag.
Second drop, eight foot plunge, lights on but helo spins through 180 degrees upon hitting the surface causing disorientation as you exit the window as briefed. A bit hairy.
Third drop, ten foot plunge, no lights, 180 spin which swings back & forth before settling upside down- any exit. Blind panic- confused helicopter pilots milling about, grasping at any limbs moving outwards & then being dragged backwards and hurled over my shoulders as I clawed my way towards an exit. "Terrible" said the staff, "Round again". So we did- twice more.
Bovvered? Nah, I just drove home looking a bit like Marty Feldman, gripping the steering wheel to stop shaking.
As an afterthought - the aircrew guys don't finish there by the way- they have to complete a couple of additional runs. The aircrew on a military helicopter have small compressed air breathing bottles with a mouthpiece and can stay underwater for longer if needs be. It sounds very simple, but apparently they have to breath in through their mouths & out through their noses as it isn't a diving demand valve that's fitted. It's amusing watching the guys that get flustered & try to breath out through their mouths & in through their noses- they don't half come up fast!