First Chapter

From Chapter One: The heart of any boat is its power plant, whether this is a small outboard on the ship's tender, or a massive reactor aboard a modern naval vessel. Regardless of size, type, intended use or the size of the vessel it is propelling through the water, the engine is top dog aboard the boat.

After the demise of steam power, diesel engines where once the most common, if not the only, means of propulsion machinery available for large naval vessels. With the advent of nuclear propulsion systems, this is no longer the case. The days of walking into the engine room, aboard a naval vessel, and marveling at the massive components of the enormous diesel engines are all but gone. In their place are the sparkling high-tech components of the new systems. So much for fond memories.

Modern diesel engines are available from six horsepower to over fifteen hundred horsepower. They are capable of running permanent and portable gensets, auxiliary engines for sail boats, main engines for power boats and even outboards for day boats, of any description.

Diesel engines remain the work horse of most sailing vessels and motoryachts, over twenty-five feet. This has come about for extremely good reasons. The main one being, naturally aspirated diesel engines seem to run forever, with only routine maintenance, fuel and air. Herein lies the key to diesel engine longevity.

Many people run their boats as they do their cars. They get behind the wheel, turn the key and go! When the car begins its early demise, from lack of maintenance, the mechanic or new car salesman becomes rich. The owner, significantly poorer. This does not have to be, but it is an all too common mind set of boaters.

There are many safety and economic concerns with this type of thinking. When a car breaks down, you pull off to the side of the roadway and call for a seventy-five dollar tow. On the water, the breakdown will only happen in an area where there is no place to "pull over". Not to mention, the tow will cost a minimum of two hundred and fifty dollars. In short, your boat is not your car, it is your boat. It requires a more disciplined maintenance schedule, if this scenario is to be avoided.

In the most simplistic of terms, a diesel engine requires only two ingredients to function: Air and Fuel. Unlike its gasoline counter part, once a diesel engine is running it does not need electricity to maintain the spark which ignites the fuel.

Its basic function requires the correct ratio of atomized fuel and air. This mixture is compressed, at the top of the cylinder, by the piston's up stoke. When the explosive level is reached, combustion takes place, which in turn drives the piston down, providing power. Simple, isn't it?

This basic function, however, requires that every part of the engine is operating at peak performance. Higher horsepower, non-naturally aspirated engines, (turbo charged, inter or after cooled engines) insist on this peak performance each time the key is turned. The naturally aspirated engines will operate a short time, although poorly, without peak performance of all the components.

I mention this, not to lull you into thinking the naturally aspirated diesel does not need the same vigilance of the turbo diesel, it does. I mention it to abolish the old adage "If it ain't broke don't fix it." Many people still believe this to be true. Their engine may be spewing oil and fuel from every conceivable orifice, missing on two of four cylinders, blowing more smoke than a fog machine and putting an oil slick on the water for miles. But it still runs, so it ain't broke. Yes, it is!

A turbo charged diesel would have shut down long before it reached this stage, possibly protecting the engine from severe damage. The naturally aspirated engine may not. Herein lies the problem of the above thinking. This lack of maintenance and concern will result in irreversible damage to the engine. I am a firm believer in repairing a problem before it is a problem. Preventive maintenance.