I've dry fitted the vee berth bulkhead so as to gain access to the space. This is where I plan to put the holding tank for the head. I'll re-use the through hull fittings, they are bronze and in good shape. The valves are another thing. As I will be cruising on the river for most of the time, I plan to use only the 3/4" inlet valve (new ball-cock) and will reinsert the 1 1/2" through hull and plug it off. I may just reuse the big gate valve after freeing it up and then plugging the top. A double shut feature, if you will. So, the question is how big a tank can I afford to fit? Rectangular or irregular shape? Decisions, decisions. 

There's a square piece of starboard lying in the bottom and the shelf which supported the water tank is also visible. It is quite dirty because the transducer had been in a tube glassed to the hull and filled with mineral oil. The tube obviously developed a leak which left the mineral oil sloshing around in this area. UGH. I have to clean this before painting.

The only way I could release the 1 1/2" through hull was by splitting the nut. That is what is visible to the right of the photo. I have already purchased a replacement.

 

I spent the day making the support shelf for the water tank. I had to enlarge the hatch and ultimately make a new hatch-cover as the tank could not be shoehorned in any other way. Everything is in place, but not permanently. I will do this after I have all the tanks, the head and all associated plumbing pieces. I think there is too much possibility of stuff having to be shifted, moved or persuaded into place to fix anything right now. So, I've made more progress.