Yup, that’s what the mechanic said.  Went out for a sail on coming into the harbor on the way back the engine started making “expensive” noises.  You know, the screeching, grinding ones.  I initially thought it was the fresh water pump, but when I took off the fan belt and tugged on the pump shaft it was tight and spun freely.  Started the engine again and realized it was coming from the transmission area.  Time to call in the mechanic.  He immediately diagnosed it as a broken stress plate spring.  Turned out that was close.  It was the fan on the stress plate that broke.  Pieces were flailing around inside the bell housing.  The “tranny” was fine, but the stress plate was toast.  We pulled the bell housing, took off the stress plate and it turned out the flywheel had to come out too due to some bolts on the stress plate corroding onto the flywheel.  A week later and a new stress plate and we’re back in motion (oh, and about $1500!)