Jamesd,
If my (fading) memory serves me correctly, the Puma has some serious issues with high CG and deck motion, as well as a startling lack of tie down points and any serious structure to fit them.
The phrase 'properly marinised' can be interpreted in a number of ways - but for my money I'd want a tough, medium sized helicopter, with decent corrosion protection, avionics suited for maritime ops, and power folding blades. Low CG, plenty of tie down points, and good all weather capability.
Puma (in its current form) doesn't fit my bill - but I'm happy to be proved wrong. SK4 does a very decent job, but it's old and going.
Best Regards
Engines