IMPROVEMENTS YOUR BOAT MAY NEED

June 18, 2013

     Or, She looked so perfect when I fell in love with her!

You are primed to come up with a creative solution.

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When I first got the boat I have now, it was all good. I liked the boat, I was learning to sail her, the cats and I had settled in well to living aboard.

Then the engine started overheating.

“Diesel engines last forever,” more experienced friends assured me. “It’s just about impossible to kill a diesel engine.” The key words there were “just about.” Any engine can be killed if the owner tries hard enough.

But it wasn’t me who had caused the problem. It was the owner before me. In the end, it seems that he had completely neglected to keep zincs on the shaft and engine. Since the engine was salt-water cooled, it required zincs in three places – on the propeller, and in two places on the engine. This is necessary because salt water is a decent carrier of electrical current and because electrolysis, the process that causes corrosion. On iron and some kinds of steel, corrosion results in rust. On bronze, corrosion results in surface pitting, and eventually, honeycombing of the bronze. The bronze turns pink and eventually breaks quite easily. I’ll come back to that in another entry.

Zinc corrodes more easily than either steel or bronze. By placing pieces of zinc at critical places, such as the propeller shaft and the engine block, the electrolysis attacks the zinc, protecting the boat parts. The zinc, however, gradually dissolves away, requiring replacement.

I just didn’t know enough about boats to see the warning signs, and very importantly, I didn’t get an engine survey done. I didn’t know to, unfortunately. I believe a good, certified marine mechanic would have spotted the warning signs.

I bought the boat in November. The following April I felt I had learned the boat well enough to take a longer trip, and left with a couple of other boats from the club to take a longer cruise. All was fine until I needed the engine to bring the sails in. The engine rapidly overheated. I had no idea why the engine was overheating and felt that the longer trip was a bad idea. We returned home.

Then the hunt began to figure out what was wrong with the engine.  I read up on engine problems, and I consulted my sailboat gurus. One of the things immediately pointed out to me was that the exhaust pipe for my boat was below the water. This was a problem because your exhaust can tell you a lot about what’s going on with your engine.

See the picture of my boat’s stern below, where you will clearly see the exhaust pipe above the waterline. That’s where it should be. Your exhaust can tell you a number of things. For instance, when you start the engine, you can immediately see whether or not the engine is pumping water. One day I forgot to open the seacock bringing salt water into the engine for cooling, and it was obvious immediately, because no water was pumping out the exhaust. While the exhaust pipe was below the water line I couldn't watch for that.

In addition, if you’re having engine problems the color of the exhaust can help with diagnosis. But significantly, this boat blew steam about 30 seconds before the overheat alarm went off. Since it was overheating a lot, that was important.

I had a boat with ill-defined problems, but I couldn’t see steam, and I couldn’t see the color of the exhaust.

It didn’t cost much to have the exhaust pipe moved. Although I was not able to save that old engine, with a new one in the boat I feel much better being able to see the exhaust.

It’s not a common situation, but if your engine’s exhaust is below the waterline, you should consider having it moved. Make sure it’s moved by someone who knows exactly what he is doing. You don’t want salt water backing up into your engine. 

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