Bonjour Nick,
I have about 60 whistles on my model boats and only 3 sirens which operate perfectly.
Not obvious to install on boats with superstructures like my tug Moulay-Idriss (I spend my time screwing and unscrewing the siren whenever I need to work on the superstructure), I have installed them on "open" boats.
They are so original that I would like more and furthermore, my friends don't like my whistles
For information, as I don't use them frequently, they tend to jam so I fill them with a lot of WD40 to help it to start again.