Power Take Off

Marinediesel offers various PTO options with all of the engines we manufacture. In fact, the list of applications would be quite large, were we to list them all. Some examples of PTO options we have provided in the past, for both marine and industrial uses include:

  • Alternators
  • Pumps
  • Hydraulic Motors
  • Fire Control Systems
  • Blower Systems
  • Lifts, Davits, and Cranes

In fact, PTO is a standardized option, and a variety of shafts and couplings can be provided, depending on the use. You need merely ask your dealer or distributor to add it to your purchase and we will do the rest!

MD VGT + Jackshaft closeup

Can I replace a marine starter with an automotive starter?

A question we are often asked, particularly since we frequently mention our use of GM engine blocks, is if there is parts compatibility between Marinediesel components and automotive components. The answer is not so simple.

Yes. And No.

Can you use automotive components on our engines. Yes. In most cases they will fit. Should you? No.


Marine parts are designed for use in the marine environment. Though sizes may be the same, the marine components are usually manufactured with different seals and different alloys to inhibit both corrosion and the intrusion of moisture.

A couple of good examples are starters and alternators.

Since the topic is starters:

  1. Starters for marine use produce the spark differently, as in they are shielded. This is due to the need to minimize the risk of igniting fuel vapors in cramped engine compartments. Automotive starters are typically not located in areas with reduced air flow.
  2. The number one cause of failure of starters is moisture. Starters manufactured for marine use are more moisture resistant.
  3. As in point number two above, corrosion is a problem with starters. The alloys used to produce the sparks are different.

So, in theory you can use an automotive starter on the Marinediesel engines. However, you really should use a starter that is classified for marine use in order to operate safely and with a long service life.

As to other components being interchangeable, a few are. You need to consult with your local Marinediesel distributor before attempting to take any shortcuts.

How rough is it out there, really?

Boating and the life at sea is full of many superstitions and beliefs that sometimes do not mesh with reality. How many have heard long time captains say something on the order of “This is nothing… You weren’t there when I was aboard that vessel in 15 m seas!”

Unfortunately, determining wave height while standing at the helm is not always very easy. In fact, most people tend to overestimate the size of waves. Why? It is due to an optical illusion. When you are standing at the helm, you are not only several meters above the surface of the water, but you are standing on a deck that is pitching. The wave trough is not straight down to you, at a 90° angle, but rather pitched either forward or aft.

Therefore, it is easy to overestimate a 1m wave by thinking it is 1.5m or more.

So, how do you make a more accurate estimate? Simple. You estimate the wave height at the trough of the wave, when the boat is most level. At that point, the angle is correct to get the most accurate perspective. This illusion was first noted by William Froude back in the 19th Century (Yes, the same person who developed the formulas for determining resistance).

VGT: THE diesel alternative to outboards

Outboards are common on small, high speed craft. Indeed, on some vessel types, they are often though of as the “default” propulsion method.


  1. They are cheap.
  2. They are easy to maintain.
  3. They provide “pretty good” speed.
  4. They do not take up much space.
  5. They are lightweight.
  6. A row of them, side-by-side “looks” fast and impressive.

However, outboard engines have some serious disadvantages and limitations:

  1. Outboard engines are usually gasoline automobile engines that are mounted vertically to a gearbox and drive system as a single unit. The forces generated by these engines are vertical, rather than horizontal, resulting in a substantial loss of power and a drastic increase in wear.
  2. Gasoline (petrol) is an explosion and fire risk, especially with government vessels or those used in the offshore industry. (Diesel is a much safer fuel)
  3. Gasoline is usually more expensive than diesel. Additionally, gasoline engines always consume fuel at a higher rate than diesel engines. (In some markets, the differential is as much as 50%).
  4. Outboard engines have a life cycle that is usually no more than a few hundred hours, at best. (You can  easily replace an outboard five times before needing to rebuild a VGT engine… Not so cheap now, eh?)
  5. Outboard engines are, by their design, limited in the number of propulsion options (You get what you get. With a VGT engine, you can use jets, surface drives, a variety of stern drives, or traditional shafts.)
  6. Diesel engines provide far more torque than outboard engines (Outboards cannot even come close).
  7. The vessel will always perform better with a VGT engine and proper propulsion system. ALWAYS.

The Marinediesel VGT Series of engines was designed to be the lightest, most powerful engines in their class. Our compact size and high power output make them an ideal alternative to the use of outboard engines. The VGT will, quite simply, fit where other engines may not.

Vessels can be equipped with Marinediesel inboard VGT engines at only a slightly higher cost than equipping the same vessel with large outboard engines, and that slightly higher cost is recouped very quickly in a much longer service life and the substantial fuel savings received. In fact, on larger outboard vessels, the use of outboards for propulsion is often equated by simply flushing money down the drain. They always cost more in the long term. In fact, many of our customers refer to outboards as “throwaway” engines. They run them full throttle until they simply break, and replace them with a new engine.


This “ease of replacement” and “ease of repair” is very much an illusion. The Marinediesel VGT Series will last up to five times longer than the average outboard before requiring an overhaul. Additionally, our remote mounting options give the VGT Series an ease of maintenance that approaches even the best designed outboard.

Additionally, the higher power and torque give a much better level of performance and control than an outboard-equipped vessel. Outboards, by design, are limited in the amount of operational control that they can provide, particularly regarding trim. A well-designed propulsion package with inboard engines will give a higher level of control and speed than even the best outboards on the market.

Finally, outboard engines are external, and thus, noisy by design. They are very difficult to control noise, and are often impossible for effective noise control.

If you want to look into the feasibility of using our VGT engines instead of outboards, and experiencing the meaning of true performance, Contact Us or your local Marinediesel Distributor for a quote today.


Choosing the right engine


Vessel design is a complex process, and every engine does not necessarily suit every project. Of course, Marinediesel would like to win every project out there in the market, but as manufacturers we understand that all engines are not necessarily created equal.

Some of the important points to consider when choosing an engine are listed below, along with some notes about the competitive advantage Marinediesel engines possess:

  • Power: Does the engine produce enough power and torque to get the job done? Marinediesel engines are usually best suited for small, high speed craft.
  • Weight: Lighter engines are best. Marinediesel’s VGT Series is the lightest engine in their class at a mere 515 kg.
  • Size: All the power in the world will not help you if the engine will not fit into a constricted space.
  • Cost: There is cost, and there is value. Marinediesel engines are usually not the cheapest, but they generally cost much less over the long term than those made by our competitors.
  • Operating Costs: Engines that require lots of maintenance, or difficult maintenance, cost far more over the long term. Our GM heritage means that our engines are reliable and easy to maintain.
  • Reliability: How much does vessel downtime cost you? Reliability pays big dividends over the long term.
  • Vibration: Excessive vibration reduces engine life and increases noise. The Marinediesel V8 beats every competitor hands down, no contest. An inline six cylinder engine can never produce less vibration. Don’t just take our word for it, though. It’s the physics.
  • Noise: Noise is uncomfortable on a pleasure boat. On a government boat, it can be deadly. What if the enemy hears you coming long before they can see you?




Choosing the Right Engine



As an engine manufacturer, MarineDiesel would love to be able to answer the question, “Which engine should I choose for my project?” with a resounding “MarineDiesel, of course!” every single time. However, that is not the correct answer to give. Different engines have different strengths and weaknesses, and ours are no different. We often get requests to quote where our engines are simply not an appropriate match for a project. Sometimes, people are just price shopping, matching horsepower to horsepower, and sometimes a new project pops up where the shipyard does not have a lot of experience.

When determining the engine to choose, price should be among the last crieria that should be considered. There are far more important questions to ask:

  1. How will the vessel be used? Our engines tend to focus on fast boat applications. They are normally not a good match on tug boats, for instance (Though sometimes, occasionally, they are suitable).
  2. How much space is available for the engine? Smaller spaces require smaller engines.
  3. Is noise a problem? Engines are tested for noise when manufactured. Noise can be controlled through both silencing and insulation, in addition, yet those items also have costs in space and money associated with them.
  4. Is vibration a problem? Some engines, such as our VGT Series, produce much less vibration than inline models, due to their physical characteristics. Additionally, there are aftermarket ways to control vibration, like the use of different mounts or couplings.
  5. How capable is your maintenance team? Some engines are more complex than others. Some require a higher level of skill to maintain.
  6. Price. Price is important, and does play a role. However, consideration also needs to be given to the cost of spares, service, and training.
  7. Life Cycle / Rating. An engine used 2,000 hours per year needs a longer life cycle than an engine used for recreational purposes.
  8. Service network. Some engines may fit all criteria, but there is no service in your country available. Engine maintenance gets expensive very quickly when performed across continents.
  9. Warranty. How good is your engine’s warranty? Some manufacturers have better warranties than others.
  10. Fuel consumption. Fuel costs, on average, exceed 60% of any engine’s operating cost. Cost savings are significant over time.
  11. Performance expectations. You need to have proper calculations made with bona fide data: Not just guesses. Horsepower and torque requirements can vary drastically with small differences in hull design.
  12. Emissions requirements. This can be important. Laws and regulations vary widely between regions / nations.

We realize that choosing an engine is complicated. Contact your local MarineDiesel dealer for personalized assistance on your project.





Bad practice: Engine idling




A common misconception in the marine industry is that you must allow diesel engines to idle before putting them under load. With modern diesel engines, this belief is 100%, completely incorrect.

In fact, allowing an engine to sit at idle for long periods of time has the opposite effect: It increases wear on the engine, increases emissions, and wastes fuel.

How did this belief get started? Quite simply, people observed truckers at truck stops allowing their engines to idle and thought it was “Best Practice.” On older diesel engines, this may have been the case with fuel efficiency, and it is certainly the case with gasoline engines. Yet, a glance at a fuel consumption curve will show that a diesel consumes more fuel at idle, over a greater time period, than at startup. Additionally, in colder climates, it is believed that idling maintains the temperature. However, all modern diesel engines that are used in cold climates have sufficient heating to allow an easy start.

Unlike gasoline engines, modern diesel engines are designed to heat up under load. The fuel is under compression by heat, combusting more efficiently, and idling does not generate that necessary heat. Sitting at idle does not provide this load, and merely increases the friction in the cylinders. The load is generated on a boat under throttle. Idling for a period of time any more than an initial 30 seconds or so after the engine is started does nothing. No extra lubrication. No benefits. All marine engines manufactured by MarineDiesel are sufficiently lubed in this time period.

Finally, add in the fact that many jurisdictions in the world restrict unnecessary idling, due to emissions, this practice is one that should be eliminated. It just creates waste.



Are there quality differences in diesel fuel?


Fuel quality is a topic that is frequently discussed on this blog. Fuel is such a critical factor in engine performance and reliability, that is why we give the topic so much attention.

Is there a difference between brands in terms of fuel quality? In other words, is there a difference between marine grade diesel produced by Shell, versus Exxon, versus any other brand?

The answer is, in theory, yes, but there are other factors that are far more important. The primary difference is the additives each producer blends with a specific brands of fuel. For instance, Exxon may add one proprietary additive to improve combustion and Shell may add their own proprietary blend.

The Cetane Number is also an indicator of fuel quality. The Cetane Number is an index of the time from injection to compression. High speed diesel engines typically perform better with higher Cetane Numbers, typically over 40.

What is far more important from an engine manufacturer’s perspective is the quality of fuel that the customer receives at the bunker. Fuel quality can vary widely based on storage conditions, infrastructure conditions, regions of the world or even within one region. These factors are often independent of brand, and out of the refineries’ control.

What is certain is the following: All major fuel producers in the world comply with strict ISO standards regarding fuel quality. When the fuel leaves the refinery, it is effectively guaranteed to be of a specific quality. Problems with quality normally arise much further down the supply chain.

All marine fuels are required to comply with the latest ISO 8217 standards, effective from June of 2012. Additionally, in regions where ULSD is mandated (most notably North America and Europe), sulfur content is further restricted and the fuel is in compliance with EPA and EU rules:

  • 15 ppm: Sulfur limit of 15 ppm (ULSD) becomes effective in June 2010 for nonroad fuel, and in June 2012 for locomotive and marine fuels. ULSD has been legislated for nonroad engines to enable advanced emission control systems for meeting the Tier 4 nonroad emission standards.

For the ISO quality standards, see the chart below:


DMX is the normal standard for marine use.