It may not be the answer in this particular case, but on many occasions when I have got stuck like this the answer has been to dismantle further, often after I have wasted a lot of time and ingenuity trying to avoid doing so.
While I welcome no longer having to remove my shoes for US airport security as I am aged over 75, I am puzzled by the logic behind this. Is there a compulsory retirement age for terrorists?
I thought that most fog signals associated with lighthouses had now been discontinued, for the reasons you state and because there are now much better ways of vessels finding their position.