Ballast Bags

Sizing, placing and filling your ballast

Ballast bags add weight to your boat so it sits deeper in the water and throws a bigger, cleaner wake — the foundation of a good wakeboard or wake surf session. They fill with water and drain empty, so you run them full for surfing and empty them for skiing, trailering or higher-speed activities. How ballast works. The heavier the boat sits, the more water it displaces, and the bigger the wake it leaves. Fat sacs let you add that weight exactly where you want it. Fill them for a session, drain them when you’re done — empty bags pack down flat and weigh almost nothing, unlike fixed lead ballast. Two ways to fill them. If your boat has a built-in ballast system, plug-and-play (PNP) sacs plumb straight into the existing pump and you fill and drain from the helm. Without an integrated system, you use an external submersible pump: to fill, drop the pump in the water and run the hose to the bag; to empty, attach the pump to the bag and run the hose over the side. It’s not a reversible pump — you reposition it for filling versus draining. Placement matters. Where you put the weight shapes the wake. Even distribution across port and starboard keeps the wake symmetrical — too much on one side throws it off. Weight in the stern deepens and shortens the wake but can make the boat slow to plane; weight forward lengthens it. Most setups balance bow, rear and centre sacs. For wake surfing, more weight on the surf side builds the wave. Types and shapes. Bow sacs fill the front storage area. Rear and locker sacs drop into the back compartments. V-drive sacs sit in the footwells behind the engine. Floor sacs lie flat in the walkway. PNP sacs are cut to fit specific boat models — Malibu, Axis, Nautique, Mastercraft and others. Universal sacs work with any external pump and the right fittings. Fittings and compatibility. Check the hose size, port threads and your pump setup before ordering. PNP sacs match a specific boat’s plumbing; universal sacs need adaptors to suit your pump. If you’re not sure what fits, send through your boat model and current setup and we’ll match it. Brands. Fly High (Fatsac) makes the widest range, from boat-specific PNP sacs to universal sacs. Straight Line (Sumo) covers open-bow and universal sacs. Hardline adds compact cube sacs for tight spaces. Care. Drain fully before storage and let the sac dry to stop mildew. Don’t leave a full sac in the sun for long periods. Check fittings and seams each season.