so I am on his puter.
The reason I machined the bottle was because it wasn't perfectly flat. I was afraid when I attached the fitting to the bottom of the jug it would crack like all of the merc bottles do.
It's been too many years ago and I can't remember if I had to machine out an alum. part to put in the bottle. Sorry brain cells ain't what they use to be. My old boat was a 1988 24 foot Carrera. It didn't have the alarm set up in the bottle. I am pretty sure I machined a part for the bottle.