Take the same, big, waterproof tractor that you used to launch in the first place ([[[2611997]]]), reverse it into the sea until it's practically submerged, reverse your RIB onto the trailer (this bit's not as easy as you might think), then just drive back up to the Lifeboat Station. Fairly simple!
Uploaded to Geograph by Richard Law on 29 August 2011
Photo © Richard Law, 29 August 2011. Licensed for reuse under this Creative Commons licence