This is the resolution for our inverter problem. Yeah! Background: Instead of using the hot water tank only on shore power, I hit the switch while the inverter was running. The remote display fluctuated terribly, then there was a high pitched squeal, and then the A/C system died. We didn't have any other switches on, but that doesn't matter. We had blown the six internal fuses within the inverter unit itself. The 175 amp fuse in the battery compartment was not blown (the one on the sidewall within the battery compartment itself and not within the battery switch hold). The test and reset buttons would not respond either, so I figured that either we blew the GFCI or the whole unit.
The inverter is attached to the sidewalls with two square shaft screws on top and it slips into the two screws on the bottom. There is also an L-plate under the inverter, but don't mess with it (it looks like it is part of the set up, but it isn't [on the 27']). We had to entirely remove the unit and remove the battery terminal end (blue panel) of the inverter to take off the back panel of the inverter. The instructions do not run you through this because it says a technician has to do this work (not sure why because it was fairly easy after Kenny walked me through it). There are 6 of those 35 amp fuses, and no one sells them anywhere in Olympia. Upon checking, there aren't even 35 amp fuses made by most of the manufacturers apparently (two marine stores and Cabelas here and no one carries them). Lessons learned: no hot water unless shore power, get a lot of spare 35 amp fuses, oh and check your hot water first because apparently we already had enough and I was overdoing it. As you all know, the engine heats the water hot enough to last for days. Hopefully, this saves the newbies a lot of work and agony. Now we have hot water for whale watching and crabbing! Happy tug owners once again!