In the 80s I dipped the tail of G5 bell 47 in the pacific , back to a hover I noticed I was spinning flat ( no roll from T/R thrust ) . I Figured I would just put it down in the sea than fly it away .On floats with a long swell of 2 ft seas light wind .
I rolled off the throttle and did a hovering auto from 8 -10 feet .My goal was to use all the rpm and slow the rotor before it hit the tail or sea .
The landing was firm and flat ,no blade strike . I pulled pitch and the rotor brake , happy to see I was upright .
Then I saw a tube had cracked and cut the float ,I was going to roll over in a minute . The blade went into the water like a slow butter knife as the ship rolled over . I was doing my log rolling dance with the ship inverted in the deep blue sea .
No big deal the long tubes on the floats were thinner that spec home made gear from metal yard tubing .
10 years before a bearing let go in flight in the transmission . The T/R drive would engaged and disengage every 5 -10 minutes ( bearing cage ).
It seemed like power related failure , so I lost my nerve after the 4th cycle . I made a low power shallow run on to the Glassy sea . lifting it back on deck ( without damage ) They sent out a rebuilt tranny . I changed it in a day but getting my nerve up took two days of test flights .