It turns out there are instructions included w/ new Kahlenberg whistles that describe changing the gap to have the whistle sound properly at different pressures.
The 117AMP whistle arrived. This is a new old-stock unused whistle.
The tonal quality of the whistle is outstanding.
A quick check shows that mounting in my planned location will be close to having enough room. My boat has an open array radar, where the antenna spins around above the pedastle. My installation has 5° wedges under the pedastle to angle it forward, so it remains flat while the boat is operating at speed, on a plane.
My plan is to mount each whistle on the arch’s flat surface, adjacent to the radar pedastle, at the rear. The taller 117AMP whistle won’t clear the rotating array at the front, but it might just clear at the rear. I need to disassemble some canvas to permit me to do a trial fit, to see if this will work.
My plan is to have the whistle on the top of the arch screwed into the valve on the interior of the arch, w/ the whistle and the valve snugged up tight against the fiberglass / gelcoat arch, at about ½" thick.
Kahlenberg 117AMP Whistle A/V Clip