Anyway these could be automated, in a similar manner to airbags, to save pilot workload?
The simplest system would be a float in a small chamber, that triggered a fast inflation. OK it wouldn't stop partial submerge, but it would stop it becoming a more serious situation like inversion. Once the pax and pilot had walked away, the heli would also be recoverable.
Maybe even link it into the hard landing airbag system suggested in an earlier thread, although airbag/float shape might not be compatible.
Mart