688 fairwater planes are nearly useless. The sail is too short and too far aft, putting them too close to the center of bouyancy. The thing was a tub at PD and lacked the depth control system that 637s had to bring water onboard in a flat hurry if you were in danger of broaching. So to compensate, you have to flood as you come to PD. A good helm/planes/DOOW/COW team can time it perfectly to be about 2000 pounds heavy when the scope breaks the surface. That's why you hear stories about 688s losing depth control...you have to run heavy at PD to keep from broaching.
Tell me about it. Nothing was more tiring that PD at even a moderate sea state.
I wouldn't have minded trying it once on another class, just for variety's sake.