The factory Gravity III ballast system installed in Supra and Moomba boats from 2002-2008 does not include a vent connection. That means any air that finds its way into the system has no way of getting out, and that limits how much water you can actually get in the system.

This upgrade kit includes everything you need to add a dedicated vent connection without drilling any holes in your boat. Installation takes approximately 15 minutes, and when done, your bag will be vented correctly ensuring any air that ends up in the bag (from trailering the boat, putting it on your lift, etc.) is able to vent during the filling process. In some applications, that can mean an additional 200 pounds of ballast in a bag that looked completely full, but was actually half full of water and the rest was air.

Buy vent kits for all three bags in your Gravity III and get free shipping!

This kit comes pre-assembled and ready for installation, just thread the new included fitting into your factory ballast bag, disconnect your factory drain line from the thru-hull fitting on the side of the boat, and reconnect it to the supplied tee fitting with the kit. Installation is completely reversible if you want to go back to the stock setup at any time (although we're not sure why you would ever want to do that), and makes no permanent modifications to the boat.

This kit is sold individually, so you'll need one for each bag you want to upgrade.

NOTE: This upgrade requires that your bag have an available port on the top that is not currently being used. Most factory Supra/Moomba bags are equipped with that port, and if you've upgraded your rear bags using our then your bag will definitely have the necessary port. For compatibility with WakeMAKERS ballast bags you will need to purchase our 3/4" DryLOK Bag Fitting.