If by chance you're reading this and are still not convinced about countersinking, this is a lifting eye I installed in 2002 for an inflatable RIB dinghy. To do this install all I did was bevel the outer hull with a countersink bit, clean the surface with acetone and install the fitting with 3M 101 polysulfide, tightened it down ONCE and cleaned up the goop that squished out.
This fitting has been bone dry for nine years and resides below water, as in COMPLETELY SUBMERGED, when the dinghy is floating.
EDITED 10/22/2013: Still bone dry and not leaking a drop at 11 years, in a fully submerged application!!