Head (toilet) stopped up

Ahh the dreaded head.  Survey says someone flushed something they shouldn't have.  Or at the very least too much of something.  There is actually a pretty simple fix for this 99% of the time.  Carefully remove the bolts holding the head to the floor. I know it's a bit full right now so carefully slide the head around so you can get to the back of it. Locate the two main wires supplying the current to the motor. Most likely red and black wires.  If you can't get to the connection feel free to cut them both one at a time. Don't worry the head is operated by 12v.  Take these two wires trim them back and reverse them. Red to black and black to red this will cause the macerator to run backwards.  The macerator is for all practical purposes a grinder.  Running it backwards will release what's caught in it. Switch the wires back to there normal positions and flush the head.  It should go ahead and work normally. If not, repeat this process and try again.  This as stated works about 99% of the time. A couple of wire connector nuts and you're done.  If this is a regular occurrence you might consider wiring in a double throw double poll switch so this can be done with a flip of the switch.  You can purchase one of these at any auto parts store in the electrical section.  I don't like anything flushed that wasn't eaten first. It's just a simple rule on our boat.  If you or your crew insist on flushing paper at least mandate them use single ply paper.  FYI   The cheapest paper you can buy in single ply is the same thing as marine paper. Just not a $1.00 a roll.  Bear in mind however a hand full of single ply becomes multi ply.  Uncle Ricky says it's as simple as that!!