Thanks for the replys.
I think putting a tank under the settee is probably the way I will go. Dependinging on the size of my water tank which is also under the same settee I should be able to fit a decent size holding tank
there. I need to get to the boat and take some measurements.
Looking through the Ronco tanks I found one that I think would fit under the v berth.(I cant find my measurements for the space) It is only an 8 gallon tank. I think it is to small for a 4 to 5 day trip whitout being able to pump