Hydroponics are often in a medium like perlite, not just water
GrowingMedium

MotherEarthNews
note the use of fish emulsion, and seaweed as fertilizer.

and yes it could be gimbaled to keep it upright!

Does the crew know it will be "at sea" for a year when they depart?

You mentioned that all the electronics fail, is this an EMP / EOTWAWKI type scenario ?

If money was no object then perhaps you have had some custom air guns made by Mr Barnes.
GLBarnes
these are not your typical pop guns!


Lee