angus99
Guru
Thought this deserved a separate discussion vs piggybacking on the "Stuck Impeller" thread.
Also, because these two impellers were easy to pull.
They are from the twin Lehman 135's on our Defever 44 and I discovered them this way after a 1,000-mile delivery trip from Florida to the head of the Chesapeake. I think there were 6 intact vanes on one and 5 on the other!
After seeing this and almost stroking out, I started collecting the bits of what I assume is neoprene downstream in the raw water system. You can see the debris from one of the damaged impellers below, alongside an intact impeller.
I learned a few things:
First, the Ford Lehman 135 must be one tough engine. Both engines were monitored routinely throughout the trip by a highly respected delivery skipper--via the temp gauges and regular direct infrared thermometer readings--and they never overheated. The exhausts were also checked hourly and no reductions in water flow were discernible. This was especially surprising after I found most of the neoprene pieces up against the tube bundles in the heat exchangers.
Secondly, I will never start a long cruise without new, or lightly used, impellers. The ones that came with the boat were likely rotated in and out of use to extend their service life.
Third, I'll probably chuck out impellers I replace even if they're intact rather than try to eek a few more months out of them. (I have already pulled them while the boat's laid up for the winter.)
Lastly, I'll check the impellers physically before, during and after trips. It was my bad that I assumed they were up to the trip . The new Speed Seal covers I just installed on the impeller housings should make that less of a chore.
If anybody has a better approach to impeller health, please share.
Better lucky than smart, I guess.
Also, because these two impellers were easy to pull.
They are from the twin Lehman 135's on our Defever 44 and I discovered them this way after a 1,000-mile delivery trip from Florida to the head of the Chesapeake. I think there were 6 intact vanes on one and 5 on the other!
After seeing this and almost stroking out, I started collecting the bits of what I assume is neoprene downstream in the raw water system. You can see the debris from one of the damaged impellers below, alongside an intact impeller.
I learned a few things:
First, the Ford Lehman 135 must be one tough engine. Both engines were monitored routinely throughout the trip by a highly respected delivery skipper--via the temp gauges and regular direct infrared thermometer readings--and they never overheated. The exhausts were also checked hourly and no reductions in water flow were discernible. This was especially surprising after I found most of the neoprene pieces up against the tube bundles in the heat exchangers.
Secondly, I will never start a long cruise without new, or lightly used, impellers. The ones that came with the boat were likely rotated in and out of use to extend their service life.
Third, I'll probably chuck out impellers I replace even if they're intact rather than try to eek a few more months out of them. (I have already pulled them while the boat's laid up for the winter.)
Lastly, I'll check the impellers physically before, during and after trips. It was my bad that I assumed they were up to the trip . The new Speed Seal covers I just installed on the impeller housings should make that less of a chore.
If anybody has a better approach to impeller health, please share.
Better lucky than smart, I guess.