A Yacht Engine

I am often asked how does a marine engine differ from an automobile or truck engine. Of course there are basic similarities, however, there are some specific differences, particularly on the engines that are used to power larger luxury motor yachts.

At first glance, one of the most obvious differences between boat engines and car engines is the cost. A marine engine, either diesel or gasoline, will cost significantly more than a car engine of equal size and horsepower. I know this cost differential has tempted many a “do-it-yourselfer” to use a car engine when their boat engine needs to be replaced. This is a bad idea, as you will come to realize as you read on about the differences between the two.

The Sea is Hard on Engines

Obviously, while they share many of the same systems and components, marine engines and car engines have been designed to work in very different environments. Your yacht’s engines will be subject to conditions of salt, water, wind, rain, sun, sea-life, etc. that a typical auto engine will never have to face. Therefore, marine engines must be more durable, and literally built to “weather the storm.”

In addition to the conditions, marine engines work much harder than their land-bound counterparts, and this is another reasons why they need to be much more durable, and why a car engine should never be used to replace a comparable marine engine.

car engine vs boat engine

This V-8 Looks Great in a Muscle Car – But in Your Yacht, Not So Much!

A typical car will only need around 15-20 of its 100 – 200 horsepower, to sustain an average speed of 65 mph. Whereas a marine engine, especially one on a 70-140Ft motor yacht, is always cranking under heavy load. The typical draw on a marine engine would be like hitching a 2-ton trailer to your car, and trying to drive it up to Pikes Peak at 75 miles an hour!

Other Differences Between Car and Boat Engines

Besides being more expensive and having to work harder, there are specific difference between the component parts and systems of marine and automotive engines. Which also accounts for the differences in the costs of replacement parts between the two, with parts for the fuel, cooling and electrical systems of marine engines costing significantly more. For example, marine cooling systems must have specialized seals, and all wiring and electrical components must be uniquely designed to protect against corrosion.

How to Extend the Life of Your Engines

The fact of the matter is that marine engines are more expensive and built tougher than car engines because they have to be. Given the environment that yacht engines have to perform in, and the high-cost of their repair and replacement, it is incumbent upon yacht owners to do all they can to extend the lives of their engines.

While it may seem counter intuitive, marine engines actually last longer the more they are used, and run continuously. Laying fallow for a while, and frequent starts and shut-downs, prevent a typical marine engine from delivering its maximum number of hours.

yacht engine repair

Proper Maintenance is Key to Long Engine Life

If you are not planning on using your yacht very often, besides for the opportunity to offset expenses, this is a good reason to consider a charter income program. As a charter yacht, your boat will have an opportunity to “stretch her legs” more often and see that her engines and other critical systems get the workouts they need.

Also, when your boat is in a charter program, and a member of our On Demand Yachting platform, you can be assured that all routine maintenance is done on a planned and regular basis, ensuring that your yacht is always healthy and ready to go for you, or your charter customers!



Operating a motor yacht can be costly. You can reduce your expenses, and avoid costly repairs by keeping her well maintained. On Demand yachting from FYM can help. If you would like to learn more, or if you have any questions or comments about this blog post, do not hesitate to contact our Yacht Management specialists, or call us at (954) 900-9968.