What it is: Supra/Moomba BagBuster Ballast Upgrade (2002-2008)

This kit is designed for 2002-2008 Supra and Moomba wakeboard boats equipped with the Gravity III wakeboard ballast system from the factory. When a bag is selected and added to the kit, quick connects will already be cemented in just like the factory bags. Because any upgraded bag will be taller than the factory bag, we include a prefabricated fill hose extension that will quick connect to the factory hose. The extension is made with the same hose and fittings as the factory connection to simplify the install. The entire installation is completely plug-and-play, takes less than two minutes, and requires no modifications to your boat.

For Use In:

For specific questions on fitment, and for possible compatibility with other models, click here.

Dimensions:

• 400lbs – 42″ x 16″ x 16″
• 565lbs – 42″ x 19″ x 19″
• 750lbs – 50″ x 20″ x 20″
• 1,100lbs – 50″ x 24″ x 24″
• 1,450lbs – 108″ x 25″ x 25″

Starting at $19.95 Buy Now »

Dan loaded up his 2008 Moomba Outback V for wakesurfing using the Moomba Gravity III factory ballast system and two additional Launch Pad ballast bags. The result as you can see from the video above is a very surfable wave. To get the most out of your Moomba Outback V Gravity 3 Ballast System replace your 400lb. rear ballast bag with the Wakemakers Moomba BagBuster Ballast Upgrade (2002-2008) or the Moomba BagBuster Rear Ballast Upgrade (2009-2011) depending on the year of your boat. Both ballast kits include the fittings and any necessary hose extensions you will need to replace the factory rear ballast bag with a larger Fly High Fat Sac.

Factory Ballast System Specs:
Bow Ballast: N/A
Center Ballast: 400 lbs.
Rear Port Ballast (Left): 400 lbs.
Rear Starboard Ballast (Right): 400 lbs.

Wakesurf Ballast Configuration:
Bow Ballast: N/A
Center Ballast: Fly High Moomba Ski Locker Sac 400 lbs.
Rear Port Ballast (Left): Straight Line Sumo V Sac 750 lbs.
Rear Starboard Ballast (Right): Empty
Extra Ballast: Launch Pad Sumo Jr. V Sac 400 lbs. (Placed on the Port side seat)

Wake Plate or Wedge Settings: Wake Plate 1/4 Up
Speed: 10.5 mph
Occupants: 2
Prop: OJ 14×14.25

Whether you’re designing a new ballast system, or trying to upgrade your existing system to fill and drain faster, one common question is how best to design the system so it is as uncomplicated (and also inexpensive) as possible.  One of the tools that we use when helping people design a custom ballast system is a product called a vented loop.

As shown above, a vented loop is a “U” shaped plastic fitting that is installed in series with the fill pump when using aerator pumps.  During filling, the vented loop is invisible, functioning as a section of hose without any limitations.  The beauty of the vented loop only comes into play when the the fill pump is turned off, which means there are no drawbacks to implementing its use.  When water is not being forced through the fill hose, air (but not water) is allowed to pass through a vent at the top of the loop, which allows the column of water from the vented loop to the fill pump to drain down to the level of the pump.  

It is this column of air (typically at least two feet long) that prevents water from siphoning into, or out of the ballast bag when the pump is not running.  Many people are under the impression that water is forced past the fill pump due to the boat running at speed, but it’s not possible to develop that much pressure, and it actually just the siphoning process that allows the bag to fill or drain.  The vented loop solves that problem by creating a break in the column of water running from the pump to the bag, so siphoning is not possible.

To function correctly, the vented loop needs to be installed close to the ballast bag in question, and as high above the water line as possible.  For forward ballast bags, the typical installation location is under the driver’s dash up near the windshield.  In the back of the boat, up under the gunnel, whether in direct drive or v-drive boats, is typically the best location.

If you have any other questions about the vented loop in particular, or ballast systems in general, please feel free to contact us.

Moomba uses one Rule 2000GPH pump to fill all of the bags in the boat. If you only have the center ballast option, then it will fill it fairly quickly, but if you’re complaining about the fill speed, you probably have at least GIII system on your boat (or even larger upgraded bags). If that’s the case the fill capacity will be approximately 660GPH to each bag. In an ideal world, that would result in around 5 minute fill times for the standard 400 pound bags, but ballast systems have lots of less than ideal characteristics. In the factory system, the biggest roadblock is the sprinkler valve manifold system that Moomba uses. Even when open, they have less than half the flow volume of the 3/4″ hose that is used in the boat. Cutting the volume of water in half results in fill times of around 10 minutes, nearly twice the ideal rate.

So what does that mean in terms of actually upgrading the speed of the system? The Rule fill pump used in the system is the largest capacity pump you can really get for this application, so there isn’t a quick fix there. Basically, there are two main options for decreasing the fill time:

1. Replace the stock single fill pump and valve manifold system with three individual fill pumps, one for each bag. In addition to increasing the theoretical fill capacity from 2000GPH to 2400GPH (or higher), the big speed up will be removing the restrictive sprinkler valves.
2. Replace the three restrictive sprinkler valves with quarter-turn solenoid valves. These work the same way, but don’t limit flow at all when open. They are expensive though, at around $60 each.

We typically recommend option 1 because it will cost less, be more efficient, and will be more reliable because three pumps are doing the work of one pump. Unfortunately though, neither one will be a simple install, it will require some reworking of the factory components.

If you have additional questions about upgrading the factory ballast system in your Moomba boat, feel free to contact us and we’ll be happy to help outline your options.