Marina Chiapas, Chiapas, Mexico
After over 2 weeks in the work yard, Sine Timore was finally dropped back in the water, 1 week ago, on a Saturday morning. Our temporary hull repairs got delayed due to a combination of screwed up work priorities by the yard foreman (other cruisers screamed louder) and an unfortunate traffic accident in which Henry, apparently the only one allowed to work on our boat, was injured when a pickup truck rear ended the collectivo (small bus) he was riding in. Fortunately for him and us, he was back on the job after only a few days of recuperation.
Once back in our slip in the marina, we started making our plans for departure. The one remaining job on our list was to replace the battery in our wireless wind instrument on the top of the mast. My attempts to entice one of the yard workers with the exciting prospect of climbing the mast were not successful, so last Monday I made two trips up there to retrieve and replace the offending instrument, now possessing a somewhat newer battery - I think we bought it about 3 years ago. So far it appears to be working much better.
There is some interesting work going on in the marina. After the damage that resulted from last year’s Tsunami, they are adding an additional meter to the height of all the posts. The main problem when the water rose was that the docks came off the posts and had new holes punched in them when they came back down. In spite of that, and the fact that the work yard was flooded to a couple of feet, no boats were damaged in the yard or on the docks. Hard to imagine what it must have been like.
With everything on the boat seemingly ship-shape, we just had to watch the weather forecasts for a suitable window of opportunity for sneaking past the dreaded Gulf of Tehuantepec - we need a good 48 hours with less than gale-force winds. Prospects looked good for a Friday (yesterday) departure. I went so far as to tell the marina that we would be leaving then. Those of you who are more observant may have noticed that we are still here.
Anticipating the Friday departure, I started doing the usual checks of all the systems and such. Everything looked real good until I went to check the oil in the engine. When I pulled the dipstick out, I was shocked to find the oil was oozing out of that hole. Indeed, upon looking further down, it became apparent that the bilge was full of oil - my precious engine oil! Something was displacing the oil in the engine. The only real possibility was water, but was it fresh water or salt water?
Because the bottom of our engine is inaccessible, it has a hand pump which allows me to pump the oil out of the bottom of the sump. I used this pump to extract a few litres of water from the engine - tasting it confirmed that it was salt water. Oddly enough this turns out to be good news. If it had been fresh water, it would have indicated a blown head gasket or heat exchanger, both of which would be major problems requiring much time and expense to fix. Salt water almost certainly meant we had a failed siphon-break in the raw-water cooling system. Not pleasant but not quite as devastating.
To explain... Basically, on a system like ours, sea water comes in through a thru-hull fitting and valve, passes through a raw-water strainer, then is pressurized by a raw-water pump that runs on its own pulley on the engine. From there, it passes through the heat exchanger, providing cooling for the fresh water of the engine, continuing through the transmission oil cooler, then finally being injected into the exhaust system, where it cools and muffles the exhaust and is ultimately ejected from the boat via the exhaust pipe at the stern.
Because our engine is mounted below the waterline, care must be taken to prevent water from pouring into the exhaust when the engine is not running. In our boat, this is accomplished by having the water hose between the oil cooler and the exhaust injection rise up above the waterline, up behind the kitchen cupboards. At its highest point, a vented loop is used which, in conjunction with a one-way check-valve, allows air to enter the line when no pressure is being provided by the raw-water pump. Needless to say, if that vent gets blocked, or the check-valve sticks, the siphon break will not work. In that case, and indeed in our case, when the engine is shut off, a siphon is created, which slowly fills the exhaust pipe, then the exhaust manifold on the engine, then the engine itself, possibly even filling some cylinders with water if their exhaust valves happened to stop in the open position. Since water is heavier than oil, the water sinks to the bottom of the sump and pushes the oil up and out of the engine via the dipstick hole.
On our boat, the vent line from the vented loop travels across the galley, behind the cupboards, runs through the closet in the aft cabin, continues into the storage compartment under the cockpit, where the check-valve actually resides, then exits from the boat through its own little hole in the side of the hull. All of this was news to me but I know it well now. I found the source of the problem right at the fitting where the vent exits the boat - totally plugged with who knows what. I was able to clear out the obstruction and confirmed that the check-valve was functioning properly. Unfortunately when I attempted to get the small vent hose off the vented loop fitting behind the kitchen cupboard, the hose adapter broke off. This turned out to be an easy fix once we found a welder in Tapachula that could solder it all together again. The total cost of the repair came to 50 pesos (about 3 dollars).The real problem though is that salt water in a Diesel engine is never a good thing. I was able to contact the dealer in Vancouver where we bought the engine some 12 years ago and got some specific instructions to follow for purging the water from the engine, part of which entailed 4 complete oil and filter changes. At this point, I think the engine problem has been solved - just some more cleanup to do in the bilge. But of course, we have missed our weather window for the Tehuantepec - there doesn’t seem to be another one predicted for at least a week.
On the plus side, the hunt for parts, oil, filters and welders did get us a glimpse of more of the city of Tapachula than we had seen before.
So here we sit, no closer to our ultimate destination in San Carlos than we were 3 weeks ago.
{GMST}14|41.9333|N|92|23.5167|W|Marina Chiapas, Mexico|Marina Chiapas, Mexico{GEND}
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