Hi Aquapore,
Although I didn't notice any noise from that area on my Bav 36 from 2002, I suggest you unship the boom from the swivel and take a close look both at the gooseneck swivel and to where it attaches to the forward end of the boom. I found considerable wear on both components, but particularly on the gooseneck swivel such that I decided to renew the swivel. A tell tale sign to look for is a grayish stain on the cabin top just below the swivel where dust from the wearing aluminium falls onto the cabin roof. I can't remember what I paid for a new swivel, it wasn't desperately expensive, and it was easy to fit. The wear on the boom where the swivel attaches was less dramatic so I did nothing with that (it looked like it would have been expensive to renew !!). Anyway, I now keep an eye on both parts. The question that remains is why did the wear occur in the first place, and from what I can remember it appeared that while the boom could swing easily from side to side, the wear on the swivel suggested that it did not move so easily. The new swivel appeared better made than the original, and may have been of somewhat stronger material, though that may just have been because it was new and not worn. My Bav 36 is an ex charter boat, and had seen an awful lot of use, in its life, and often by persons who were not too bothered about taking care of it, so I would not really expect to see this sort of problem on an entirely privately owned and operated boat.