Personally, I wouldn't be very inclined to try to swim the canal. Basically, not only are you going to increase your risk by becoming cold and wet, potentially soaking your gear, but you could get run over by a boat.

If you are warm dry and healthy, you are not in immediate danger. Don't put yourself at increased risk to cut a bit of time. Well... Unless you are Bear Grylls. In which case... Have fun!