Equipment
Vent Line
The overflow tube on a ballast bag that lets trapped air escape so the bag fills fully and prevents it from overfilling beyond its compartment.
A vent line (overflow) is a necessary part of any plumbed ballast bag system. Without it, the bag will either trap air and fail to fill to capacity, or it will overfill and grow larger than its compartment, potentially causing damage. The vent fitting must be positioned higher than the bag when full.
For wakesurfing specifically, the vent line should be routed toward the bow so the bag does not siphon or drain while the boat is leaned and underway. Proper venting is essential to getting consistent, repeatable ballast weight session to session.