I would NOT lie, superglue is NOT waterproof ... squirt it you mouth, glut your teeth together ... in a couple of hours, or more, the bond will fail, you can get your teeth apart ... if you doubt this, research it on a manufacturers website ... they will tell you, it is NOT waterproof.
Now, it may "catch" in a crack and slow the leak to an imperceptible level, however, the glue, itself, is NOT waterproof--i.e., the bond cannot be maintained to surfaces when immersed in water.
But then, you CAN prove me wrong, find a manufacturer stating the glue is waterproof and present the URL here ...
Regards,
JS