I place an 'X' mark on the nav point and then write down the X-mark number against the time in a little book I keep on my desk, I call it my "Little Nav Mark Book". Its red you see, and looks rather nice. I mainly use a black pen to write the time as it contrasts well with the white pages, but sometimes I go a little mad and use blue.
Its not an elegant solution but its handy enough, unless of course you are unable to write, in which case its complete pants!
