Casio G-Shock. Different models, features, etc and can take quite a bit of abuse. I have a watch fetish and own far more watches then any man has a right to, and for the money you can't beat a G-Shock. Now if you want to pony up several grand, I can point you to a couple that make a G-Shock look like something you'd get from a cracker jack box. But for normal guys to wear while on duty and not have to worry about it crapping out on ya, a G-Shock is the way to go and they're built like little tanks. Price runs from about $50 to +$2500, so you can find one to fit any budget.
One other piece of advice....get a G-Shock that has a cloth/web band. Most G-Shocks have a resin band and that's the weak spot for watches. ALL resin bands eventually crack and break. A web band holds up better and easily replaceable if needed. Comfort also plays a roll, and for me, a cloth band is more comfortable and lighter. I hate resin bands.
I would also like to add that if you want to spend a little more($150 to $300...and up), look at Luminox watches. I personally prefer Luminox to Casio (unless you're talking old Casio...old casio dive watches are worth every penny), and I like the look of a Luminox over the G-Shocks. Stick with either Luminox or G-Shock and your Sailor will be a happy camper.
Thanks for the suggestions. I'll pass along the info to my SR's grandmother.
We got our sailor a Casio G-shock when he PIR'd 2 years ago - it's been a great watch for him.