lljkk laughing at the coast guard checking you're OK! sounds like a lovely swim!!
SkiGirl007 I can't swim butterfly, although it IS something I am getting better at... SLOWLY (while trying not to drown) I'm nearly there....
I have only learnt this SINCE joining Masters a year ago. As is the case with many Masters, there are bits of us that don't work too well, so we can't do x or y for risk of injury, and that is OK. To begin with, I swam the fly part of the IM in FC, and then swam the correct strokes for the remainder.
I know other Masters in higher lanes than I (and MUCH faster), that don't do FC kick (knee/back issues) or will only do some drills due to shoulder issues. If they are keen to get you onboard - and I can't tell you how much I've benefitted from being part of the Masters squad, it's AWESOME - then have a chat with them and see. I think they will be happy to have you.
Glitteryfrog Absolutely just keep going, it will get easier. I can swim thousands of metres in a pool, but stick me outside and my head kicks in and tells me I need to stop. I've worked hard on it this summer and have managed to get a few hundred metres of continuous open water swimming without freaking out. Slow down to go faster/further :D Focus on being as streamlined as poss, legs and feet up, breath out fully and take your 6 strokes, then another and another and you will get there. for 6 strokes, try 9, then 12, breath on every three to pace yourself through it.