Reminds me rather of a shallow skills dive during my IDC off the shingle beach at Brighton (England) in November back in the '90s. Getting in wasn't a problem, though there was a lot of surge and the shingle is almost like quicksand. Doing skills in a monstrous surge was a lot of fun, but hey this was an IDC and no-one wanted to say they couldn't do it. Getting back out was the killer. The shingle beach has a short and sharp incline which is particularly steep where the waves are breaking on it. Combined with the very soft nature of the shingle and the tremendous undertow this made getting out well-nigh impossible. The process took me over ten minutes and all the other candidates similar lengths of time. The CD was quite a slight woman and she had no chance, being tossed around like a cork in a storm. After the rest of us were all out she had made nil progress, so we all took off our gear and went back to help her. Working together we managed to get her and her gear out in around 20 minutes. In the process two sets of gear that had been dumped on the large shingles at the top of the slope, well back from the drop-off, were undermined and slid down into the water. In total getting us and all of our gear out of the water took longer than the hour we had been under. There were no big rocks around and no danger of getting hit, but drowning was an ever-present risk.