Oddly enough Gator Guards Keelshield isn't recommended for floating docks or even for resting on trailer rollers, have a read through the faq's here
https://www.gator-guards.com/pages/faq
I fitted a Keelshield strip myself and it's stayed on so far but I was very particular with preperation, especially waiting for a day with the correct temperature as the adhesive requires the hull to be above a certain temperature to cure properly. There's loads of videos on Youtube for DIY installation.
I found the cheapest option was to purchase from the USA via Amazon and the lifetime warranty was still valid using this method. The warranty wasn't valid purchasing from a UK retailer as they aren't authourised dealers.