Today was the day I was going to do the whole swimming lap. Now, don't worry: we have to swim two laps for the 750 meters, so one lap is 375 meters.
First I had to swim to the first yellow buoy. Which would have been about 125 meters. I only needed to stop three times. Then on towards the second yellow buoy. Another 125 meters. Another three stops as well. And then the home straight. Guess what: 125 meters and yes, three stops as well.
All in all, it took me a little under twenty minutes to do the lap and for a first time I was quite pleased. I do need a bit more training though, if I am going to do two full laps and then continue with the cycling and the running/walking.