wrote:

How much of an issue is corrosion on the Island Line? Are they really on the
pier for long enough periods of time that it can become problematic?


Good questions!

I'm no expert on corrosion, but I do know that dissimilar metals in a
marine environment can cause no end of problems. Once exposed to salt
spray, an electrolytic reaction starts between the metals using salt
water as the electrolyte. There is very little you can do to stop it.

So the issue is not how long they spend on the pier. I think the issue
is that they get sprayed with salt water and that sets up a corrosion
mechanism that continues while they are away from the pier, and into the
long term.