5K (swim) training

Don't know if this is really the place for this as it has little to do with running, but there is a ton of information out there on where to begin for running training for various race lengths, but little that I'm aware of regarding 5k open water swim training. I think I'm going to do an ocean 5K race in May and wonder if some of the former/current swimmers have any experience here? For me, swimming is weird in that a super hard effort results in maybe a minute faster a mile than a fairly moderate effort - I don't know if I should model a running training for swimming, just swim as much as I can take, how to mix in VO2 max/sprint stuff, etc. I may have to back off a little as my shoulders are starting to feel like they are really taking a beating...

Any thoughts?

Yea, You're nuts.

This way, after your first ironman, you can start looking at double ironman events.

Me nuts? Swimming is easy compared running - and it wasn't good enough to beat the cr@p out of us with marathons, now you and Martin have to do it in ultramarathons too!

Ocean 5K??????? Yup, nuts. I've done several Open Water swims (back in my college days), but they were all 1-1.5 miles and in freshwater. Sorry, nothing great to add except that you're nuts.