Re: @A.P. Veening Economists - In 1889?
If I was a billionaire, I think I'd have a boat with the heat exchangers made out of platinum iridium alloy, because I could. No corrosion worries.
If the rest of the boat is made of non-platinum group metals then you'd need to be careful of galvanic (dissimilar metal) corrosion. Platinum's at the far end of the galvanic series so it's a threat to most other metals. It's relatively easy to address if you can separate the metals with non-conductive barriers (e.g., paint), but I wouldn't say "no worries."