My front end iMac with 10.14 lasts about a month or so before a panic. Currently:

$ uptime
16:24 up 38 days, 5:01, 9 users, load averages: 4.79 7.10 6.14

As you can see from the load, that poor iMac is getting a workout. The OS gives up after a few weeks. I just got a new M2 Pro mini... not thrilled with Ventura, considering installing Monterey. But we'll see. Hopefully it stays up longer.

A front-end Linux server that hosts haproxy and other stuff:

$ uptime
  21:24:45 up 528 days, 21:36, 1 user, load average: 0.52, 0.43, 0.33

Packages do get updated regularly, but clearly the kernel hasn't been updated in quite a while. That machine only reboots when I tell it to. I cannot recall when I last experienced a forced kernel panic/reboot other than power related on any Linux machine. I recall back In The Day our SunOS workstations with uptimes in multiple thousands of days.

Um, carbon fiber is used quite a bit in racing sailboats. Carbon fiber masts and spinnaker poles are very common these days. There are growing numbers of racing boats with carbon fiber hulls. I think this is a well understood issue, and carbon is quite safe in salt water. Most boat owners use a bottom paint, whose purpose is primarily to retard growth on the bottom. More and more boats are going naked on the bottom though, in lieu of a toxic bottom paint. Me, I still use VC-17 with a bag of pure copper dust mixed in.

Larry