In general I would say for your voyage a water maker is waaaaay more important than a parasail, but as mentioned that water maker, at 1.5 gph, is pretty much nothing but a waste of power, depending on your power generation. If you run it four hours a day, that's 6 gallons. They say 4 amps but I bet in the real world it's probably more like 6, so that's 24 amps per day. Can you afford that, and do you want to listen to that thing hammering away for 4 hours a day?
All that said, I think it comes down to the advantages of being able to make water and what that means for your route
and how much you have to carry on deck
and your water usage patterns. For me, there's nothing like taking a freshwater shower
every few days offshore
. It's seriously restorative.
Since you're making the passage
with your wife, the most prudent thing to do would be to let her decide