This is what I used for all but two, the two bilge fittings were for 3/4" hose and all others 1" hose. The two very front floor drains have a grey PVC elbow that the through hull fitting has to screw into, so the hose nipple gets cut off down to where the threads start. The threads on these new fittings are ever so slightly larger, I wrapped sand paper around them and rotated it to slightly reduce the size. They will only thread in around four turns, but I used thread sealer to insure a sealed fit. It was a very big challenge doing these, if it were not for my problem solving, and never give up attitude, I don't think it would of been doable. I actually made my own spanner wrench out of 1/4" plywood for the retaining nuts, there just isn't enough room for a big Cresent wrench or other tool.
A couple very important things to note, first is that it's very easy to cross thread the big retaining nut since there are two flat notches at the end of the threads for a wrench to be used. These notches make it easy to cross thread, trust me when I say you don't want this to happen. Second is the barbs that the new fittings have really hold, once the hose is slid over these, it will not pull off even with soap or grease in there. So make sure you have everything correct before attaching the hose. Third is the hose clamps, one of the hardest things to do is get a wrench, nut driver, or screw driver on the clamps. It is all done by feel and the clamp always wants to spin when you need it to stay in a certain position. You have to tighten the clamp just enough to slide over the hose and still be a little snug. Not one part of this job is easy, if someone offered me a few grand to do their boat, I'd pass!
View attachment 9911