Re: Isn't that what the watches with the numbered bezels are for?
Not sure why you got the downvotes Ken - a timing device and a dive plan written on a slate is a good backup strategy (see my other post below).
There are diving watches with nice big luminous hands and dots that will suffice but people tend to prefer something electronic - I have a buddy device that does a bit more than just timing and it's slipped into a pocket.
Mind you, if I'm on my rebreather, it has a Shearwater computer on my left wrist and I have my OSTC on my right wrist. The OSTC is independent of the CCR/Shearwater so acts as a completely independent backup.
Which means between my dive buddy and I, we have 4 "full" computers and two HUDs