Swimming

I know there's no definite answer to this, but what roughly is a good time to do 1500m of crawl in a 25m pool (i.e., 60 lengths)? As some sort of comparison, you could say that doing a century on a bike at around 18mph is good.

I've started swimming more recently and am trying to improve my technique. I'm really fit on a bike, but I don't seem to be able to swim particularly fast at the moment and would like to have something to aim for.

I've watched a few short technique videos and am trying to put them into practice. To add to those, does anyone have any real generic crawl tips that may help?
Swimsmooth.com gives good guidance.

(It's all swimsmooth or total immersion these days.)

Catch-up drills and finger drag drills are good for technique.

A good benchmark for anything I do it to take the world record and double it - So 29 minutes for 1,500m,