Sounding the Sumburgh foghorn. 2:22 video:
https://www.youtube.com/watch?v=iHCmzvzCmhI
More:
https://www.sumburghhead.com/foghorn
https://en.wikipedia.org/wiki/Sumburgh_Head_Lighthouse
Previously:
https://www.homemadetools.net/forum/...858#post144357
https://www.homemadetools.net/forum/...704#post139904
https://www.homemadetools.net/forum/...383#post166044