Requires you to have a slowfall or the engineering prof for a goblin glider.
Swim out in the water east of Ruby Lake on the map till you enter Time Lost waters and start to get fatigue. There you can mount up. Fly all the way straight up, then move towards Ruby Lake and activate slow fall or goblin glider and simply drifting easilly onto Ruby lake without the bother of albatrosses.
Good luck on collecting them Ruby Droplets! Cheers
You could also do this without the benefit of any other device and try to hit the lake as you plummet downward at a rapid pace, hoping that you were high enough and moving fast enough to land in that tiny little lake.