Originally Posted by seasick
That head is a Wilcox Chrichidan (sp). Known locally as the corn cob crusher. That military grade head will suck down anything you can throw at it. I have had several in my various boats and have one currently. Rebuild kits are readily available.
With any head onboard, regardless of how reliable. You want to rebuild them regularly. So that you head off (no pun intended) any problems, before they get a chance to crop up.
That, along with regular maintenance
, & you shouldn't have any troubles, knock on wood. As I've had more issues with land based commodes, than those on boats.
Ah, & for most (sailors anyway) this is commonly known, but... you have to ensure that guests onboard understand that Nothing. As in, less than Zero. Items go into the head, other than biological waste, & TP.
To the point where such a sign needs to be well posted in the head compartment. Along with a warning on the sign which states, that guests who clog it, especially via putting other (improper) items into it, "get" to fix it. Via the Skipper's supervision & instruction.
This, of course, with a proper demonstration as to it's use, for newbies. Along with having them cycle it under supervision, as a dry run, so that they definitively Know how to operate it.
Generally such avoids 98% of any problems.