So many great tips in this thread, thank you, it's great to know how to be smart!
Also this one, "On the ship, I use a plastic snap connector to the sea pass sleeve, and because of the wind on open decks, I actually stick the sleeve in my shirt pocket while it is attached to the lanyard around my neck. My point about the phone-sized sleeves is that they generally have a hard-plastic seal to which the lanyard is attached, or they have reinforced holes (like a grommet) through which the lanyard cord passes."