Pura Vida has two turbocharged 3208T Caterpillar Marine engines, these engines use raw water to cool a radiator called a “heat exchanger” in the marine world. Every 5 or so years on a salt water boat you need to service the raw water components, my engines power twin disk transmissions that have a gear oil cooler that uses raw water to cool the transmission fluid. My gear oil coolers were showing signs of age and a little water seepage around the sensors I knew it was time to re stack them. Cable Marine removed these gave them a acid bath, inspected them and rebuilt them with new gaskets and reinstalled on my transmissions. You can see the housing in the photos below, its thick brass and the cooling bundles are aluminum with brass fittings. the brass housing has zincs at both ends that help protect the metals, the way we counteract galvanic corrosion is to add a third metal into the circuit, one that is quicker than the other two to give up its electrons. This piece of metal is called a sacrificial anode, and most often it is zinc. In fact, most boaters refer to sacrificial anodes simply as zincs.
Anything metal on the boat that is in contact with the salt water has Zinc installed, like propeller shafts, trim tabs, rudders, and engine cooling components
old zinc vs. new
Gear Oil Coolers reinstalled