Storm Frank knocked a basking shark off course into the shallow waters of Skelmorlie last Wednesday lunchtime, sparking fears about its safety.
Resident Scott Stewart took the remarkable footage, which you can see here.
Scott, 27, had spotted a photo of the basking shark on Facebook, and decided to go down to the shore at the Meigle, with his dad, Kenny, 53, to check.
Scott said: "I was a bit concerned as to why it was further into the coast than they usually would be.
"It was quite a sight - the video footage doesn't do it justice - it was massive. It appeared to be struggling with the weather conditions, and was slowly moving along the bay. We followed it for around half an hour to make sure it kept away from the rocks, and it moved around 600 yards along the coastline. We thought it might have been tangled at first, and we followed it till it got to the sandy bay area away from the rocks."
'News' columnist Dr Philip Cowie of the Field Studies Centre, said: "It is an unusual sighting for this time of year, and surprising.
"I am guessing there may not be that much zooplankton about with the poor water visibility, so there is not much feeding; it normally would be deeper. 
"It looks like a big adult. You can see it is really shifting to try to get back out to sea and deeper water. It wouldn't be feeding in this area normally - you can see the amount of sediment that is being churned up by the waves and this would be a real issue in terms of clogging its gill rakers.
"The closest I have seen basking sharks was in Kames Bay, Millport, a couple of metres off the rocks but it was still in deeper water. So it could be a healthy shark that has strayed close to shore and then is battling the unusually big swell - or, possibly, not that healthy and struggling. Little is known about the winter distribution of basking sharks - but those that have been tagged typically show that in the winter they tend to go very deep (100+ m depth) - possibly feeding on deep-water shrimp, some have been shown to go off the Norwegian shelf.
"Hopefully it is just a healthy overwintering adult still finding enough food in the Clyde."