Morse doesn't take that long to learn and they could teach it on board to save time/money.
Sextants & celestial nav are a tad more tricky and do take longer. With a sextant I could find my position anywhere on the planet within half a mile or so (fine in the middle of the oggin, and you have land & bearings for anything closer to shore). Never did really understand figures on the plane of the rational horizon and haversine proofs though, but my nav was accurate :-)
I have long thought that abandoning some of these systems is not always a great idea. GPS is clearly a good system to target to incapacitate your opposition so having some backup would be sensible.
Mines the bag with the Nories tables and a Nautical Almanac