I was so glad to find this thread.
Coffee is sacred to us so having multiple and failsafe systems is key.
A manual grinder is a high priority item.
Roasting beans is not so bad, perhaps roast over the Magma grill
The ease of heating water
for coffee on a longer crossing would be the tougher part. Perhaps run the generator
in the morning to brew and charge the battery
We pretty much decided french press on the boat.
At the house I have an old diner Bunn O Matic automatic with two warmers on top. The unit is late 70's and still serviceable, parts
used in new units today. 12 cups in under 3 minutes.