Electrolysis is going to be a big problem with any aluminium hull in saltwater.
I worked on aluminum head fishing boats built in the early 70’s that are still working fine. Granted, they were hauled yearly and zincs were used liberally, so I’m not sure that would meet Navy requirements.
Add vibration to give everything a nice added mechanical threat aimed at every new crevice and pit which is a new and upplanned "stress raiser" weak point. It's a friggin nightmare.
You must not try to invent this wheel, but try to learn as much as possible from the Aussies mainly, who have been building these as "fast transports" for a long time.
It was our experience supporting the East Timor situation that convinced our Navy we needed these types of high-speed ships. The Aussies were ferrying materiel from Oz to E.T. at a dizzying pace, leaving our big slow LPDs etc in the dust.
We must study those earlier Aussie ships, now pushing 20+ years old, to see what goes wrong and how they solved the problems.
But once the water jet tunnels etc begin to resemble swiss cheese, the boat is really screwed. That is the guts of the boat. To get access for a total replacement/rebuild of that area means removing engines, shafts, turbine blades, giant hydraulic actuators, etc etc.
Then there is corrosion in the hull framing and plating itself...another problem. If it has started, it becomes very problematic about the future of the hull itself.
The aluminium hull isn’t as much of problem if it’s isolated from everything else on the ship. You drop a penny or a piece if electrical wire in the bilge of an aluminium hull, if there is even a little salt water around and it will eat right through the plate!
Yes, but the Navy combats it by reversing the normal current flow to near zero and by the addition of sacrificial anodes.
Absolutely SWAMPSNIPER. Absolutely. Israel experimented with all aluminum welded cargo containers in the early seventies. Absolute disaster as electrolysis literally consumed them in a relatively short period of time. Other than electrolysis they also were susceptible to damage in normal handling that was way costly to repair given their construction, and the requirements to repair. They could only be repaired in sophisticated ports such as the United States where the costs were much too high relative to an international trade.
This relates to most anything aluminum and saltwater, or similar commodity bleeds such as say a cargo of hides to a foreign land to make shoes, or other leather accessories. The salts wiped out the containers quickly.