Thursday, October 23, 2014

Surf City Here We Come

Surf City, NC
34 26.691 N 077 32.000 W

Last night in Mile Hammock Bay, we were treated to the special kind of entertainment that only Camp Lejune Marines can provide.   We were surrounded by explosions and automatic weapons fire all night long.  It sounded like an ISIS attack.  Actually, it was less noisy than a previous time in the same location.  On that previous night they were practicing rappelling down from hovering blackhawk helicopters 100 meters away.

I promised to report on our problem with salt water intrusion to the primary coolant antifreeze.  Here's the short version. We motored from NC to VA on the outside.  Midway through the trip I checked the engine.  It and the engine compartment were caked in salt!!!  When we got to the DSC canal I first cleaned up the salt, then  I investigated.  I found the expansion tank full to overflow, and I found the radiator cap's spring broken.   I emptied the tank,n flushed the engine with fresh water, refilled the engine with antifreeze, and put on a new cap.  Since then it behaved normally.  But I wanted Daryl, the mechanic at Sailcraft, to check it out.

My theory centered on the heat exchanger.  My spare exchanger is shown on the picture below.  Salt water goes through the tubes and the plenums on both ends.  The whole thing sits in a bath of antifreeze. Rubber O-rings on each end separate the salt water from antifreeze.  (I say "raw water"/ "primary coolant" sides, but some other people  say "raw water"/"fresh water."  No matter.)

My theory was that only a tube leak or a O-ring leak could cause raw water to leak to the primary side.  Daryl, had a different opinion.  He said that an O-ring might have initially not seated right.  That would be exacerbated if the radiator cap prevented the primary side from being pressurized.  Normally, there is little pressure difference between raw and primary sides.   But the O-ring should "roll" with time and seat itself which seems to be the case.   Daryl also found a leak in the raw water vented loop up high that could have sprayed raw water around causing the engine to be caked with salt.

The vented loop leaked because of a cut in the hose.  I had two hose clamps on a place where there was only room for one, and the second clamp caused a cut in the hose.  I put two there because the insurance surveyor wrote that up as a defect in our last survey and the insurance company insisted that I remedy it.   The surveyor used only book learning rather than common sense.   I remember being very annoyed that he wrote up findings that included three things that I disagreed with.  But once written, the insurance company insists on strict compliance.  I think that surveyors should review and discuss all their findings with the owner before submitting the report.

In any case, Daryl replaced the vent hose, but declined to take the engine apart to inspect the heat exchanger.   Sailcraft also installed an anti-wrap fair lead near the masthead to prevent my jib halyard from wrapping around the jib when we furl. (We had that problem for the first time in the past few weeks.)   Both jobs were one in only 90 minutes and we sailed away after paying only $150 for a surpisingly low bill.  It made for a good day.

Since leaving Sailcraft, I have been paying special attention to the engine cooling system.  It is functioning well.  The expansion tank level is constant.  Not a single drop of salt water has leaked anyplace.  Things seem good.

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