The weed doll had a few names — Michil, others called it Breedeen and a small few called it Father Neptune. After the parading of the town, the doll was taken down to the sea where it was cast out as an offering to the sea, a simple ceremony which drew the curtain on the bathing season in the town.There's a little more detail on the history of it in another article here.
"It was said if the doll turns up in the Back Strand it would mean the next season would be a very good summer."
I'm just working on some research for Là Fhèill Mìcheil (which falls around the autumn equinox), and this happened to pop up on an email list I'm on. I thought I'd share seeing as it piqued my interest.