Finally finished "re-installation" of the Air Head toilet. The boat was modified after the orirgal owner purchase it. The holding tank, pumps, hoses vent and toilet were removed. An "Air Head" toilet was installed. Unfortunately the marina that did the work took a few shortcuts, including using the switch and power cable that went to to original macerating pump to supply power to the small computer fan that was in the overhead fitting, where the original vent hose was installed. The overhead fitting was installed shoddily to a dorade then the vent hose come straight down, into the center of this tiny compartment. The existing fan required the power switch to the boat to be on at all times, as this is a composting toilet...
I took perfectly new Nicro solar fan (has a built in battery, so it runs 24/7) and modified it to fit the roof and the depth of the overhead. Then purchased a new 90 degree fitting from Air Head and made trim rigs from Starboard plastic to adapt the 90 degee fitting to the fan. Additionally, I installed a vent hose disconnect fitting to allow the upper part of the toilet to be removed for service, without having to unscrew the existing vent hose.