In message , at 12:28:57 on Tue, 6 Aug 2019,
Harry Bloomfield remarked:
Roland Perry submitted this idea :
However, you don't do it like that - the correct method is to open
the paddles both ends, which will at least double the flow compared
to a lock full ever five minutes.

No need, they could just open one gate and open the paddle/sluice in
the other gate.

That's not normally done because too many gates close themselves when
your back is turned. Not least because that's a natural effect of the
direction of the water flow. But sometimes it's just because they are
warped and rather "springy".
--
Roland Perry