This was one of my greatest finds while roaming around looking for sailing stuff. I grew up with a ship's clock but there was a discussion one night - or early, depending on how you look at it - about why the clock had to chime every 15 minutes. We got it down to 1/2 hours and then hours, and then ... well you can see where this is going.
But now it is on my PHONE! and I can make it chime whenever I want. Or not. You can program the chimes, and even set when you want to chimes to silence or come back on. IT WILL ring if you put your phone on "do not disturb" at night.
It really is a beautiful thing. Oh - there are some cool items on the Weems & Plath site to check out for sure... so make sure you go there - AFTER you head to the app store.