if the stock thermatic ( ? ) hub on the fan is operating correctly, it only locks up when hot. so ,if you had the fan buried in anything less than near boiling water it should free-wheel and not cause to much problem. Usually when I hit deep water the fan throws water because the fan does spin (like a front drive-line on a rig with manual hubs and part-time 4x4 will spin some while driving down the freeway) but since the clutch is cool enough it lets the fan be stopped by the water.