$30K a year is ~$82 a day, or ~$160 a day for two, which seems quite a bargain.
I assume that's an inside cabin and includes food and entertainment but does not include tipping (which may or may not be optional), laundry, internet or alcoholic beverages.
I would do a year on a San Diego long range sport-fisher, but not on a cruise ship unless the stage shows were changed out for each leg of the trip.
I imagine it's not one cruise, but rather 100 plus cruises tied together, same 10-15 shows for months.