How many thru hull fittings is alot for ballast system. I am re plumbing my ballast system so that when emptying it goes over the side rather than back through the bottom of the boat. I have a reversible pump system. <BR> <BR>Right now i have 3 vent holes for the bags,and 1 for the bilge pump all on one side of the boat. I plan on adding two more thru hull fittings on both sides so that when emptying the water out of the bags it shoots over both sides. This would be 5 on the strb side and 1 on the port side.

Just T into your vent lines and place check valves on the vent side and emptying side of the T. <BR> <BR>If you don't want to put anymore holes in your boat.

A good friend of mine has 4 vent holes (middle, front, and 2 rear) and 4 drain holes

I have my vent and drain lines together without a check valve. Just make sure the drain lines goes straight out the boat and the vent is above the drain line. <BR><img src="http://www.wakeworld.com/MB/Discus/messages/3183/774710.jpg" alt="Upload">