What is best way to fix stress cracks on bottom of surfboard ?

Question

two stress cracks appeared yesterday that run run from rail to rail (perpendicular to 1/4" wood stringer) on polyester/fiberglass 9'6" longboard about 3' from nose.

Note. the cracks are about 8" apart and run parallel to each other and there is no damage to stringer or to deck (that I can see with wax there).

Answer 1

either leave them until the board cracks more, or you have to do the regular buckled board repair.  cut out the section, refill it and reglass, but if they are hairline cracks, stop doing floaters with your longboard

Answer 2

duct tape