Carbon fiber rod to replace ceramic shaft..

Its called Multiaxial Cyclic Fatigue and it effects both carbon Fiber and other Epoxied materials. Long time soaking in Saltwater degrades the epoxy the coats the carbon fiber and is basically comes apart.

How long this will take But from what I can find it take quite some time for this to happen so using them for awhile and replacing it with new one might be the way to deal with it. From the sounds of it you would still be money ahead.

 

Edit, did not read what last poster wrote

 

The only problem with carbon fiber is this, as soon as you "cut" you are breaking that epoxy coating, and you have to re-epoxy the ends, which isnt a big deal, im BIG into cars, and i have a carbon fiber hood, trunk lid on my mustang, and i had to trim it to fit,the hood is great, but the trunk lid wouldnt close right so i took a sander and grinded the edges a little bit to make a proper fit, and well i didnt epoxy because i didnt know, and that was a 1200$ mistake, its now raising, and looks like garbage, so i had to put a new one on, and re trim it and re-epoxy it and now its great

 

2nd Try
Yes, no and maybe
The document you link to is about hop tubes, ie sideways strength is all epoxy and next to nothing fiber.
It is also all about the epoxy, different epoxies different properties. Like polyamide to polyethylene, and everything in between.
Fiber unharmed but plastics do not like water but in different degrees.

Can take from months to forever, no one would know if one does not get the documentation from the producer og the used epoxy.

 

Then I got a name of a glue you ought to try.
Epoxies are a little limited in case of opaqueness, there are some poluerethanes witch is much better looking, more like mirroring in fact. If you are interrested pm me, and I'll get the name on Monday