I'm sure this isn't going to impress most of you but the strongest currents I've personally experienced were at Elphinstone reef in Egypt. I've dived there on multiple occasions in various conditions but on one dive we had an 8-10 knot reversal (south to north) current with very much non-trivial up and down wellings..... and that at a little before 8 AM....
I'm pretty sure the locals thought it was serious because they wanted to cancel the dive but only let us go because the least experienced diver was a DM with 650 logged dives.... and I have to admit, it wasn't relaxing. We spent most of the dive trying to find nooks and crannies to "hide" in so we could keep our group more or less connected to the same dive plan....
Another group who tried to dive the same reef at about the same time we did got picked up by a Zodiac something like a km off the reef in open water.... In my case, I was only able to control my depth in a washing-machine-bandwidth from 5 to 18 metres (I was shooting for 10). Another diver who I met there (and this is someone who I was sure could dive....A higly experienced (GUE) North Sea wreck diver) said that in similar conditions he gave up and swam into the reef and physically held on at 52m (165ft) because he got caught in the downwelling and couldn't handle it....
Needless to say, it wasn't something you want to do for stress reduction. It was ... stimulating.... exciting.... but not your typical early morning reef bimble ....
R..
I'm pretty sure the locals thought it was serious because they wanted to cancel the dive but only let us go because the least experienced diver was a DM with 650 logged dives.... and I have to admit, it wasn't relaxing. We spent most of the dive trying to find nooks and crannies to "hide" in so we could keep our group more or less connected to the same dive plan....
Another group who tried to dive the same reef at about the same time we did got picked up by a Zodiac something like a km off the reef in open water.... In my case, I was only able to control my depth in a washing-machine-bandwidth from 5 to 18 metres (I was shooting for 10). Another diver who I met there (and this is someone who I was sure could dive....A higly experienced (GUE) North Sea wreck diver) said that in similar conditions he gave up and swam into the reef and physically held on at 52m (165ft) because he got caught in the downwelling and couldn't handle it....
Needless to say, it wasn't something you want to do for stress reduction. It was ... stimulating.... exciting.... but not your typical early morning reef bimble ....
R..