Dry suit boots filling with air and pushing the boots, and fins, off the body and, consequently, leaving you with no control
I hadn't bothered mentioning this here before as I felt it's not terribly interesting and probably something a lot of you have already experienced.
However, having heard of someone having this experience I feel the need to underline the problem as it was the start of an incident pit for me and could have resulted in an unpleasant outcome.
Below is an email I sent last year describing the incident but, in brief, I was in a strong undertow choppy surf and, having surfaced, my wing would not hold air. My reg was out, my secondary was not in the necklace and I was carrying a lot of weight.
I was being knocked about all over the place on the surface and the surge/undertow was pulling me in all directions below (very shallow) with my uncontrollable fins acting like rudders going in different directions. I went through a series of actions to remedy my situation but, being reg-less, my natural instinct was to stay on the surface and breathe, which was exhausting.
Anyway, while I suffered a cacophony of catastrophe in the shape of various failures, the point I want to underline is
the debilitation from no fins being doubly as bad when they're still hanging off and urge people to ensure that if they don't have a perfect boot fit, get them changed, wear thick socks, wear gaiters ................ don't be without control
Personal email so very descriptive and colourful 
Throughout the summer of 2006 I was trying to sort out diving with a single tank adapter for 2nd dives off boats as I only have twin 10s. My twins require only a 9" gap rather than the standard 11" so I have a single tank adapter which is in 2 pieces and my single cylinder is a dumpy. I have an extra long cam band on which to carry some block weights. I dived this under Swanage Pier and, apart from all the lurching, it was ok-ish but I wasn't particularly happy and wanted to try it out again. I have now given up on it completely.
So, I was carrying about 19Kg of which only 3 was ditchable on my belt.
I hadn't dived New Haven before but my buddy had and, as I'd dived with him before and had good faith in him, I was content to shore dive there. We agreed a plan incorporating that we would swim out along the breakwater wall, keeping it in sight, and return with it.
It was probably a bit too choppy for me given my short ar$ed 5'4" (and a bit) and the weight I was carrying but I didn't recognise this. There was a fair bit of surf and a lot of undertow and surge. I found I had to fin very hard and as I was finning my little bottom off to catch up with my buddy the sea was knocking me about quite a lot. I was getting pulled and pushed in different directions.
Next I felt my fins were off. I tried to secure myself between two big lumps of rock/wall to deal with this and then felt both fins were off. As I was being knocked all over the place and had no fin control I was having immense difficulty getting to my fins. My buddy was still swimming ahead and had not realised I had complications.
Eventually I had to invert in a U to reach up to my fins only to find the fins were still on and it was my drysuit boots that were right off. I looked like both my ankles had been broken!
I figured I wasn't going to be able to sort that out being buffeted all over the place and decided to ascend. ( We weren't deep at all) Once on the surface I was now being bashed about by waves and I fear the f-ing great rudders on my feet with the surge and undertow were now working in different directions to make any control impossible.
Fine, I'm up, inflate wing. Ha ! Air's going in, I can hear it, I tested it before we entered but it ain't staying there! Reg's not in mouth, I'm being thrown around all over the place and sinking. Tried drysuit but exhaust valve is open. Alternate reg is not in it's necklace and I have no way of finding any regs as I'm being thrown about big time and using all limbs and strength trying to get above the surface and breathe. I pulled every muscle in my upper body and I really have no idea how I did manage to keep dragging me and all that weight up. I did but I also ingested a lot of sea water and was becoming exhausted rapidly.
I know my mind, pretty methodically, went through all the things I could/should do and at some point I found myself feeling there was nothing left to do so what was I going to do now. I didn't have any dodgy thoughts but I think I was right on the line of panic when my buddy arrived.
Quite remarkably I didn't grab him or anything. I just communicated my fin problem and no air in wing issue in-between my sinking moments. It's almost amusing as he said to me "put your reg in" to which I replied, quite calmly (!!) " I don't know where it is". He then grabbed me and calmly told me I wasn't going anywhere and he had me but the waves were still splashing over me and I tried to use his alternate but it was pretty thoroughly secured and one wave hit just ripped it from me, or me from it. A lot of time, air gasping and sea battering seemed to pass while we were trying to work out how to deal with the situation.
I'm not sure what made me do it but I just squeezed hard on my wing inflation button, pushed myself on my back and shouted "tow me!" What a bossy cow !
So he towed me to the wall and I was exhausted and feeling really sick (that's salt water for you). I clung to the wall catching my breath while he removed my fins, such as they were. The waves were still crashing over me and it wasn't even easy to cling on to the wall. I tried to heave myself up with the waves but couldn't and my buddy ended up helping me get my kit off and on the breakwater wall (bit at 90 degrees to wall) and he then had to get up there and drag me on it like a beached whale. Embarrassing or what !
I examined the circumstances and kit over a good 5 days and found my the wing shraeder valve was loose and the double flange was shredded and must have been like that since assembly (new wing). I did go to Wraysbury the next day, diff kit, but then my dry suit inflation failed Ha ha ! I learnt a lot and I think it was a pretty good example of a cascade of problems.