Here's another finding we come across frequently when inspecting vessels with cored fiberglass fin stabilizers. As with any deficiency I come across more than once, I save it as a Quick Insert Phrase within InspectX so that it's very easy to enter into the report while working in the field.
Most of these stabilizer fins have a metal skeleton frame attached to the fin's stainless steel stock. The frame is most often cored with a closed cell foam and fiberglass encapsulated. Sometimes the coring is molded, and sometimes it's injected. Either way, it is likely that a few things contribute to this laminate separation developing, and a good adhesion bond is certainly not aided by the constant and rapid movement of a large cored surface submerged in water.
Here's an example of a Quick Insert Option phrase I have saved and ready for when I come across this. Feel free to copy/paste this phrase into your version of InspectX adjust to your liking.
I save it under the "Underwater Hull and Bottom Inspection" Category under the heading of ANTI-ROLL CONTROL STABILIZER SYSTEM FINS. I usually mark this observation as a 'C' or a 'B' depending on its severity.
Common fiberglass laminate coring separation was identified and marked in the sides of the stabilizer fins during the percussion sounding of the underwater hull surfaces. Investigate further, and service/repair in accordance with good marine practice as necessary.