The fixed window drains are for interior condensation. Look between the lower teak trim and the glass, all the way aft in the channel. The hole is probably plugged with stuff so you can't see it easily. Try running a small screwdriver through from the outside. If the tube came out easily, then water has been seeping around the outside of it and messing with the plywood.
J. R. Good
Plures Naves Quam Mentes