My boat still has the original head that came with it in good working condition and I am on the fence whether I should keep it or not. I am on the verge of fairing and painting the bottom and if I am going to patch over the through-hulls now is the time to do it. I am wondering, has anybody successfully used an existing head with a by-pass into a removable holding tank? And if so, where did you put it? Also, if I did decide to go the porta-potty route what sort of capacity could I expect (I am hoping to do three to four day cruises with it )? And lastly, are there models that fit beneath the hinged cover under the V-berth? Any input would be greatly appreciated,

Stephen