Corrosion is an absolute curse. I get quite emotionally involved when I see once brand new shiny products corroding away. Products that may have cost you a lot - cars, air conditioning systems for example. Manufacturers are to blame. Seeing an A/C condenser turning to rust outside is unforgivable. It's all about being made down to a price, using mild steel and inadequate coating, no doubt. My wife recently bought a new electric bicycle - made in the Far East, of course. We left it uncovered one night. No rain but wet with dew the next day. Already the bolts holding the pannier were rusting. Unforgivable!

As for cars - at least they have improved a lot, but seeing important and desirable Classic Cars reduced to lacework by the dreaded "tin-worm" is disturbing. The marine and oil industries use cathodic protection with zinc or an impressed current. Why can this not be used on other products?

I couldn't agree more.

My air conditioner outdoor unit required resurfacing within 12 months of new, no warranty on the cabinet.

One of my pet hates is the outboard motor manufacturers who insist on using mild steel plated nuts and bolts on their salt water series of motors.

Another is the pool pump industry which makes pumps with mild steel shafts even with the understanding that most pools are either salt or chlorine, both of which attack the shafting over time.

Good examples of thoughtless construction methods by so-called engineers and the "throw away" world.

The expression: "Don't spoil the ship for a ha'p'orth of tar" comes to mind.

Translation: proverb Don't risk the failure of a large project by trying to economize on trivial things.

My preferred version is "penny wise, pound foolish".
No regional dialect required. I thought it was an actual ship being spoiled!

Good comments. Too often, manufacturers and consumers confuse price and cost and decisions are made based on lowest price, not on total cost. With that said, on to your question about using cathodic protection to address corrosion problems: for cathodic protection to work there needs to be a complete circuit for current to pass through. In marine or pipeline situations the ship hull, or the interior of the pipe are immersed in an electrolyte (water, seawater or whatever liquid the pipe is carrying) and electrical current can pass through the electrolyte, the sacrificial anode (often zinc) and the metal that is to be protected (the ship hull or the pipe). Unless that electrical circuit is there and continuous, cathodic protection won't work. Galvanized zinc coatings on steel do provide cathodic protection to the steel substrate on a localized level, but if ruptures in the coating get too large the cathodic protection of the coating breaks down.

An old time pipeline engineer once said " you never really own carbon steel, you just borrow it for a while".