Easy to get the wrong end of the stick. It's pretty well known that the helo crews on the UK south coast like to practise landing on moving craft and the original poster was just saying that it had happened to him twice, big thrill for the kids (of all ages, I have no doubt) and here are some photos. It was almost as certain as night following day that someone would then make a joke about constantly needing to be rescued.
The two big ones (Sikorsky S91) are for "Up North", Shetland and Stornaway. They are roughly the same size as the old S61 (the current helos).
Down South (Portland and Solent) the replacements are AW139 which are significantly smaller than the S61s they replace. It has been asked if they are too small. It is all on "pprune" the flying scuttlebutt.