View Single Post
Old 10-28-2018, 02:16 PM   #18
firehoser75
Guru
 
firehoser75's Avatar
 
City: Nanaimo
Vessel Name: former owner of "Pilitak"
Vessel Model: Nordic Tug 37
Join Date: Feb 2018
Posts: 1,703
DDW and others,
Flushing your raw water side (often) with fresh water is a good way to help "stave off" marine age (basically the ravages of corrosion in the salt (air and water) environment that our salt water operated boats live in). If you flush regularly with fresh water (and store the raw water cooling side cleaned of salt water), you can greatly extend the time between having to fully service the various heat exchangers, gear coolers, aftercoolers, etc. and avoid the probability of overheating your engine (at least better of odds of doing so). Salt water in a hot environment (like inside our engine's components) will form a limestone like substance in the cooling passages which will only be removed (once hardened) by relatively aggressive measures like sending out to the rad shop for acid cleaning. Fresh water flushing will increase the time intervals between this type of (costly and/or time consuming) servicing. I just took apart my aftercooler for routine servicing (after 2 full seasons and about 400 engine hours) and there was no corrosion (even though the cooler consists of a "dog's breakfast" of dissimilar metals), and no calcium buildup at all. After properly reassembling with lots of grease, I can now leave this component for 4-5 years before servicing again, instead of having to look after it every 2-3 years. By the way, I service the cooling system more often than I could possibly "get away with", but I would rather be on the safe side. As far as zincs are concerned, I am certainly not an expert on this area, but I trust Tony Athens of Seaboard Marine. Unless I am reading his advice on this incorrectly, he says stay with zinc even if flushing with freshwater. His website has tons of great, free advice based on his training, education, and many years of experience. By the way, I am not associated in any way with him, or his business, just a grateful boater! His website is: sbmar.com.
Hope this info proves helpful,
Tom
__________________
Tom
Nanaimo, BC
firehoser75 is offline   Reply With Quote