I'm in process of putting in an integrated bow sac. I want to tee into the overflow and vent lines of my KGB sac. If I remember right, when my KGB sac overflows, it comes out the Port thru hull. Not sure why though? Is there really any difference between a vent and an overflow? On the KGB sac, the fill/drain line is at the bottom, and the overflow and vent lines come out the top. I don't understand why the overflow only comes out the port when filling? If I turned the bag a little, will it come out the starboard? I'm curious? I'll definately be using check valves in these lines though.

Sounds like your overflow line is coming out the port side. Vent lines and overflow line are essentially the same thing. Turning the nag will not do anything since your overflow line is ported to the port through hull.

If your familiar with the KGB Ballast in the 205V hull, you'll know the vent and overflow lines are right next to each other. Is it just the way the bag is filling that the water always runs out the port side first? That's why I was curious to just turn the bag a bit so the "vent" line is slightly lower than the "overflow" and see if this would cause the overflow to come out the starboard side then? Not that this all matters, but I just want to understand the ballast system completely before I do the install.

on mine I used both of the KGB overflows and vented the the center of IBS(Intergrated Bow Sac) out the starboard with check valve and used top on port side of IBS and vented it out the port side of the boat also with a check valve. Both the overflows from KGB are filling my IBS on the bottom. Never had any problems filling or emptying. Not nessesarily right but just how i set mine up. Also dont know if you plan on replacing the factory KGB but if you fill the IBS by using the overflows it will explode under the pressure eventually, and it will scare the SHAT out of you I know LOL.

greg, I don't get it, you said you never had any problems filling or emptying, then you say you blew up your KGB?? I'd classify that as a problem! lol! Did you replace the KGB with a fly high and now the system works fine or something?

OK small filling problem one time LOL. Yes I ordered a 400 lb tube sac from flyhigh and replaced the original KGB and yes it works fine, that was just a heads up on the KGB. The KGB will work for a while but it isnt as durabale as the FH sacs.