Hello all, Royal Navy gunnery instructors I am told, use a whistle for training. But what I need to know is what type of whistle?. Has it a special tone? are they, or were they made by specialist company's? or just plain old whistles. I have scoured the internet for answers to no certain end and decided to come here for the correct answer!. The types I have found reference to are 'The ACME Thunderer' , and old fashioned Police style whistles made by Hudson of Birmingham. Hudson also made Military whistles, but were either of these used or just one definative version/tone? A stupid question I know, but one I need an 'official' Navy answer to!