Actually I disagree on the need for the missus to be able to handle the boat under sail. Obviously, this would be a plus but I also think it is one of the things that brings a lot of fear to non-sailing spouses..."What happens if my hubby has a heart attack" or similar variation.
The only reason for a woman to NEED to be able to sail the boat alone is if the hubby is incapacitated. If he IS incapacitated...she needs HELP for him...not to continue to make the passage. So...instead of sailing skills what she needs to learn is:
1. Getting the sails DOWN.
2. How to get help:
EPIRB,
SSB Emergency Operation,
VHF Mayday prcedures AND how to give the position of the boat from the
GPS.
3. Turning the engine on and driving the boat under power.
4. In the worst case of a spouse overboard items 1 and 3 are of immediate concern.
These things are relatively easy to learn and do not require strength or skills that take time to develope.
Obviously a spouse that CAN sail and enjoys it is a huge advantage in cruising, but it is my observation that many do not enjoy the actual sailing even though they may quite enjoy the cruising life.