Just jumping onto this thread! I have my first sprint tri in early July and like the OP I am a pretty useless swimmer. I don't have too many worries that I can do 400m but I will be very slow. My favoured stroke is crawl and I'm reasonably strong at the stroke itself, it's the breathing at the same time I cannot do!
Im trying to find someone to give me a few lessons so I can improve my technique.
My question is that the pool at my gym is only a small one (15m) Is it worth swimming up and down that 30 times or is the turning at each end giving me a false benefit. I do have a 50m pool but I can only get to that once a week or so.
I can 'easily' do 100 miles on the bike, with hills on just a bit of extra training. Running 26 miles takes weeks of consistent training. Also, its pretty obvious but you can coast a little on the bike, drafting or downhill, allowing your legs a few seconds rest every now and then, not so much let up on your own 2 feet!