Ballast tanks, pumps, hoses and fittings must be properly winterized to prevent freezing damage during winter storage. Because of the complexity of preparing a ballast system for winter storage, as well as the possibility of extreme damage to the ballast system if a preparation error is made, MasterCraft recommends scheduling an appointment with an authorized dealers service department to have a certified technician to perform all winterization procedures, including ballast winterization. 

MasterCraft uses a -50 F RV type, nontoxic, propylene glycol based antifreeze to winterize every boat built at the factory. Any antifreeze meeting these requirements is acceptable for MasterCraft engine, ballast, and freshwater system winterization. Be aware that colder climates may require this same type of antifreeze with a -100 F temperature rating. 

To winterize X, XT and ProStar models: 

1. Completely empty all ballast tanks and bags of any water that may be in the ballast system.
   

2. Remove all ballast bags (if applicable) and re-attach the bridge connector (pictured right) to the ballast thru hull vent hose and the hose to the ballast hard tanks. Completely drain and store the bags in a dry place.
   

3. With the rear ballast bags removed and the bridge connector in place, identify the three ballast thru-hull vents (see guide to each model in this Owners Manual. Most models have two vents on each hull side toward the stern, and one vent forward of the helm on the starboard side). The ProStar only has one optional hard tank ballast, see guide to each model in this Owners Manual for the ProStars vent location.

4. Add one gallon of -50 F RV type nontoxic propylene glycol based antifreeze to each of the three thru-hull vents (the ProStar only has one vent). Colder climates may require this same type of antifreeze with a -100 F temperature rating. 

5. Once the antifreeze is in all three ballast zones, use the manual ballast override switches mounted on the dash to empty the tanks. This will push antifreeze through the ballast system, across all pumps, hoses, fittings and intake valves. Be cautious while using the override switches as antifreeze will be pumped out of the intakes mounted to the bottom of the boat. 

Some models have check valves equipped on the ballast lines. On such models (X46 and X10 rear bags, X20 KGB tank) pour a small amount of antifreeze into those vents (see guide to each boat in this Owners Manual). The antifreeze will sit in the line during storage. 

To winterize NXT boats: 

1. Completely empty all ballast tanks and bags of any water that may be in the ballast system.
   

2. Remove all ballast bags (if applicable) and re-attach the bridge connector (pictured to the left) to the ballast thru hull vent hose and the hose leading to the ballast hard tanks. Completely drain and store the bags in a dry place.
   

3. With the rear ballast bags removed and the bridge connector in place, identify the three ballast thru-hull vents on the hull sides of NXT boats.
   

4. Add one gallon of -50 F RV type nontoxic propylene glycol based antifreeze to each of the three thru-hull vents. Colder climates may require this same type of antifreeze with a -100 F temperature rating.
   

5. Because the NXT uses a different style ballast system than X and XT models, the antifreeze will stay in the ballast system during storage rather than being immediately pumped out.
   

Upon reactivating the boat the first time after storage, run the ballast system to pump out the antifreeze (the engine must be on and the boat must be in the water). 

WARNING:  The original bridge connector in the ballast system must be reinstalled if the optional plug-in bags are removed from the system. Failure to do so will result in any water in the ballast system evacuating into the storage compartment, potentially flooding the storage compartments. This could sink the boat, resulting in serious injury or death.