Is this Cavitation Errosion?

It does look like it could be, and with no coolant additive the possibility increases...I would use the recommended additive to see if this corrects the problem...DCA or SCA..

The customer noticed the problem. Then since the problem was ongoing and the water was being removed frequently due to repairs, this last trip ran without any additive.

That piece is informative and well-written. If the engineer hasn't bothered to read the manual, he (or she) should at least read the article.

In the 1960's the International Harvester B414 tractors wet silinders got"rusted" through only on one side from top to bottom, about 20mm wide. This was fixed by making the silinders a tighter fit ,top and bottom; The piston gudgeon -pin was off-set more and Aqau Clear added to radiator water. We also pressed the waterpump impellor closer to the casing...to prevent cavitation and better pump action.

This solved the problem of the bad dezign.

Hello Lelbar 1 Where didyou get your liners? the proper ones are clad to match your engine block. Flush your system and use dumb old Prestone. If you are hot from manuver when you make up to the dock don't shut down cold. keep your raw water exit temp, below 130 F. when running hard. If that dosn't work, talk your banker into some new power. The big yellow ones work great! Stay out of the bight,and spin that wheel. Godspeed patrick

The cavitation I have seen looks more like a "Micro-Cutting torch" and actually goes into the metal, not surface build up.

Cavitation erosion is usually on the thrust side of the cylinder about half way down the cylinder on the out side of the liner. The failure occurs when the coolant finally wears it's way though the wall of the cylinder.

The cavitation occurs when the engine is at high load and the thrust force of the piston skirt is causing high frequency vibration to cause the "boiling effect" on the outer surface of the liner. This will finally cause a hole to form and coolant will enter the crankcase and the combustion chamber. You will find a hole, probably quite small, and a scored appearance inside the liner where the water was entering and upsetting the lubrication layer.

You don't say what the type of failure occurred. Be sure to use "Nalcool" or "Napacool" or similar product, That will stop the cavitation from that source. Use the proper antifreeze mixture to prevent rust and lubrication of the water pump.

The pictures show a rusty covering on the liners which shows poor rust control and possibly poor engine grounding. Be sure that the engine coolant is not a path for electrical discharge. In other words be sure that all ground wires are in place.

Hope that helps......