Some disclosed bladder closures comprise a first rigid member adapted to be secured to a first side of a bladder opening and a second rigid member adapted to be secured to a second side of the bladder opening opposite from the first side. At least one fastener is included for clamping the first and second rigid members together to seal the bladder opening. The fastener is rotatably mounted in the first rigid member and comprises a latch positioned on an outer side of the first rigid member, a shaft that passes through the first rigid member, and at least one tab that engages with a portion of the second rigid member when the latch is rotated. The latch pivots at least partially around the shaft to engage with a projection of the second rigid member that extends through a hole in the first rigid member to lock the fastener in place.