I have a 1979 Hunter 30. It currently has a SeaLand 911-M28 head/holding tank. The M28 holding tank only hold about 8gal. of waste, is there an upgrade option available within reasonable cost. This head "drops" the waste into the holding tank on which it sits. I could squeeze a holding tank in the v-berth, but that would require a new head(that pumps). Any tank options to increase the holding capacity? Do you know what the original equipment was? Since I have a Y-valve for overboard and pump-out, is it legal to pump when more than 3 miles off shore? Thanks