Fresh news from ECD a couple of weeks ago was part of their EC135 plans for 2005 included an "Offshore package" to consist of ADELT, vibro recording & anti-corrosion measures. They also have a corrosion manual in preparation.
Depends which engines you go for but, (no doubt the manufacturers will say), so long as they get washed frequently, you'll keep them fairly sweet
- concur with JTT comments & questions, especially PBH as the sensible option. Interestingly, as Turbomeca regard the whole of the UK as a "saline environment", there are lots of people keeping an eye out for corrosion related issues, especially those near the coasts!