Strange “torpedo” in top of mast ?

In a marina they had this small catamaran with a “torpedo” on top of the mast. Do any of you have any idea what the purpose is ??

Link to Youtube video

Sailing to Torre De La Horodada in Spain

We continued south and arrived in the last city Torre De La Horadada before the border to Murcia. Because of the Corona restrictions we can’t continue and have to stay for 10 days on this side of the border in our current province: Alicante.

Club Nautico Torre De La Horadada turns out to be a quiet place to spend some nice sunny days. Well quit except for the fact they have probably the most noisy excavator in the world 🙂

Click here to watch on Youtube