Nelson made his way over to the multi-million pound yacht, which was parked in Monaco, in a dinghy to attach his homemade sign that dubs the vessel the "BHS Destroyer".
"Good of Sir Philip Green to rename his £100m yacht to something more appropriate. I was glad to help," the comedian, who is notorious for stunts, tweeted after his low-key renaming ceremony.
Nelson, whose real name is Simon Brodkin, is the same stunt-loving comedian who previously threw a bundle of money at Sepp Blatter and shouted "Sepp, this is for North Korea in 2026".
Green's yacht has gained almost as much attention as its owner this summer, as it mooched around the Aegean Sea while the former BHS owner was busy being labelled "the unacceptable face of capitalism".
BHS stores across the country are in the process of closing down after the chain collapsed into administration 13 months after being sold by Green, who has been described as running the company like a "medieval fiefdom", to Dominic Chappell's Retail Acquisitions for £1.