Currently, the Royal Canadian Navy only has 3D printing and CNC mills in its Halifax dockyard. By the end of the next decade (2030) I can foresee some of that technology going to sea, initially on supply ships, but eventually on all the frigates.
Consider what happens on board an arctic patrol vessel that breaks a critical pump a thousand kilometres from Halifax. If they had a metal 3D printer or milling machine on board, they could built a temporary pump to keep them going for a couple of weeks until an official replacement pump-arrives. Even a custom plumbing adapter would allow them to jury-rig a much larger or smaller pump to an existing system.
With modern electronics you can carry print or cut files for every part of your ship on a thumb drive or three.
Or what if a Canadian warship is transiting off the coast of Central America when the mission suddenly changes to supporting earthquake victims? First they need photo recce drones, then they need IR drones, then they need thermal imaging drones, then they need to deliver fire-extinguishers, then they need to deliver fresh water, then they need to deliver water filters, then they need to deliver medical supplies, etc. One model of drone auto-pilot can quickly have a dozen different air frames wrapped around it.