Oh yes...BE afraid...be VERY afraid!!
This may seem a bit odd, but anybody who lives with a teenage boy knows that what comes out of them at times seem to defy phisics. I'm in the process of buying my first boat with a marine head. I live with a 17 year old that seems to clog the house toilet several times a week. This seems like a desaster waiting to happen. Should I be concerned?
If he clogs the household toilet, you definitely do NOT want ANY manual marine toilet. An electric toilet is ONE good suggestion....however, only the pricy all-china "thrones" have a macerator powerful enough to grind up wet wipes. Even the most basic macerating electric toilet is $500+...You'd be looking at $700 or more for a "throne."
So IMO, your best solution is a self-contained system...an "MSD" portpotty. Don't panic...it's not portable (though it can in a crunch)...it IS a portapotty, but a version designed to be permanently installed and fitted for pumpout. It has a lot of advantages over the "standard" marine toilet and holding tank, but the big advantage for you is, it's clog proof. Best of all, it's less than $200.
A 5-6 gal model holds about 50 flushes...you'd need at least a 25 gallon holding tank to hold that many from a marine toilet. There have been several discussions about MSD portapotties in this forum in the last few months...do a search for "MSD portapotty" to find 'em. Check out the Thetford 365 MSD.
http://www.thetford.com/Home/Products/PortableToiletsHome/PortaPotti365MSD/tabid/160/Default.aspx
No matter what you decide on, be sure to have no toilet paper or tissue or papers towels available in the head except "quick-dissolve" TP, so that he cannot flush anything else. "Quick dissolve" cheapest no-name or institutional TP that practically dissolves in your hand when it even gets damp. (That's all "marine/RV" TP is, but at 3-5x the price it sells for at Sams, Costco or any grocery store). 'Cuz if ONLY "quick-dissolve" TP is used, even if an overload does clog the toilet, the clog will dissolve on its own in a couple of hours. And, since solid waste is actually at least 75% water, it dissolves very quickly too. All you need is a little patience.
Do a little homework...then come back with the additional questions I'm sure you're gonna have...I 'll be glad to answer 'em.
