Manufacturing Lead Times



MarineDiesel engines are built by hand. This gives our customers a level of quality assurance that they cannot get anywhere else. Since some of our engines are sold as customized to the application, in many cases this is the only way to produce an engine meeting specifications.

Unfortunately, with such care to detail, this requires time. Most competing manufacturers operate on a three month lead time, from order to shipping, and this is generally our lead time, too, in most cases (Though some manufacturers can me less, and other much longer). Of course, we sometimes have particular models in stock, or out dealers and distributors may also carry inventory, but for orders over a couple of engines, a nine to twelve week lead time is normally necessary.

Now, regarding spare parts, 99% of spares are on the shelf, and our dealers are required to maintain inventory on the most common spares. In either case, spares are always available immediately, if not at the dealer level, than directly from the MarineDiesel factory in Sweden via express courier.

New Video Showing NorSafe Magnum 850S with VGT450



The following video is an installation of the VGT450, SOLAS approved by our partners, Bukh, on the Norsafe Magnum 850S rescue boat.

The vessel specifications:

Fast rescue boat designed and manufactured according to latest SOLAS Classification Society and National Authority requirements.

The rescue boat has excellent reliability, manoeuvrability, and seakeeping abilities in order to fulfil its prime function – to provide an effective means of search and recovery for persons missing at sea. Design and construction fulfil the need for reliable, low maintenance standby and operation. When installed with an approved davit, the boat fulfils the requirements for fast rescue boats on offshore installations and standby vessels, and is fully compliant with latest requirements for Ro-Ro ships. The boat is further designed to operate away from the Mother Ship for extended periods, with sufficient range for long time operation and large walk around cabin providing a protected and comfortable environment for crew and passengers. The lay out and performance of the boat also allow it to perform other roles including, dive support, inspection, patrol, survey and work boat duties.

Technical data: Magnum 850 with twin waterjet

Length overall 8,37 m
Beam 3,27 m
Height 3,20 m
Height, keel to lifting point 2,35 m
Capacity 17 persons
Crew 3 persons
Weight boat with equipment 4.300 kgs
Weight with equipment and 17 persons (SOLAS) 5.703 kgs
Lifting arrangement Off Load Release Hook

Engine: Inboard diesel 2 x 450 hp VGT 450

Propulsion: 2 x Waterjet Hamilton HJ274

Speed with crew of 3: Approx. 50 knots


View Video on YouTube:

Visit NorSafe Boats Website


Updated Power, Torque, and Fuel Curves, VGT Series



MarineDiesel is always innovating. Always updating our product lines to meet our customers’ needs.

We recently put togather the following document that illustrates the fuel, power, and torque curves in detail for our VGT Series of marine engines.

Some important considerations to note:

  1. In terms of fuel consumption in g/kWh, MarineDiesel’s VGT Series is among the lowest in the market.
  2. Note the flat torque curves of the VGT engines. The VGT Series provides a high, flat torque curve compared to the peaks and valleys so prevalent in competing products.
  3. Note the very gradual power curve. There are no sharp drops, like on competing engines.

These curves prove the superiority of the VGT Series when compared to any other marine engine in the market today. Our VGT Series is specifically designed with the performance requirements that high speed vessel need in order to complete their missions.

Add in the highest power at lowest weight of any other engine in the market, and you have an unbeatable combination of power and performance in the world.

Characteristics of Different Fuels



Different fuels have inherently different combustion characteristics (They burn in different ways and hold different amounts of energy). When considering alternative fuels, it is important to keep these characteristics in mind, over and above merely considering cost of fuel and cost of operation. The chart below demonstrates different fuels and gives an easy “at a glance” comparison between fuel types:

fuel characteristics


Comparison of Auto-Ignition Temperature

The auto-ignition temperature is the temperature at which fuel will ignite without a flame or spark. In respect to the auto-ignition temperatures, LPG, CNG, and LNG are safer than gasoline or diesel.because the auto-ignition temperature is much higher.

Comparison of Peak Flame Temperature

The flammability range is the difference between the leanest (LEL) to the richest (UEL) mixture of fuel and air that will burn. Fuel with narrower ranges are safer to work with, but are less versatile because they offer less choice of air / fuel ratios. CNG has a peak flame temperature of 1,790 deg C / 3,245 deg F, which is 187 deg C / 337 deg F cooler than peak flame temperature of gasoline at 1,977 deg C / 3,591 deg F. The peak flame temperature of LPG at 1,991 deg C / 3,614 deg F is only 13 deg C / 23 deg F (Less than 1%) higher than gasoline.

Comparison of Energy Content

Energy content per unit of fuel (energy density) is an important factor affecting range and power output of internal combustion engines. The higher the energy content of the fuel, the more power the engine will make.

Volumetric Efficiency

The amount of air entering an engine at a particular throttle angle and load is fixed. Any fuel added to the air before it enters the cylinder will displace an equal volume of air and will reduce the volumetric efficiency and power output of the engine. Reductions are as follows:

  • Diesel – Less than 1% (approx.)
  • Gasoline – 1-2% (approx.)
  • LPG – 4% (approx.)
  • CNG – 9% (approx.)

What is LPG?

LPG is “Liquefied Petroleum Gas” Commonly known as propane C3H8, a combustible hydrocarbon based fuel. It comes from the refining of crude oil and natural gas. At normal pressure and temperatures, propane remains in its’ gaseous form. At lower temperatures and / or  higher pressures, propane becomes a liquid.

Propane is odorless and colorless. For safety reasons, propane is required to be odorized. There are currently three grades of propane available: HD5 for internal combustion engines, commercial propane, and propane / butane mixture for other uses. The exact composition of propane varies slightly between different parts of the world and different refineries. Compared to gasoline, the energy content of LPG is 74%.

What is CNG?

CNG is “Compressed Natural Gas”. Natural gas (CH4) is a naturally occurring mixture of combustible hydrocarbon gases found in porous formations beneath the earth’s surface. Natural gas is created by the decomposition of plant and animal remains, under great heat and pressure, over very long periods of time.

Natural gas can be found as:

  • Non-associated gas: Free gas not in contact with significant amounts of crude oil in the reservoir.
  • Associated gas: Free gas in contact with crude oil in the reservoir.
  • Dissolved gas: Gas in solution with crude oil in the reservoir.

For safety reasons, CNG is required to be odorized. Compared to gasoline, the energy content of CNG is 25%.

Derating – What does it mean?



Engine buyers are often presented, as a sales pitch, with a lot of gobbledygook about horsepower, torque, how great an engine performs, and so on…

How much is actually true?

With MarineDiesel, you get what you pay for. If you buy 500 hp, you get 500 hp.

Nothing is as frustrating to a vessel operator as receiving a new vessel and finding out that the engines are not producing the power that they thought they had purchased.

Why do these scenarios happen?

It is related to derating.

Engines can be either intentionally derated or unintentionally derated.

Intentional derating occurs when the customer asks the manufacturer to change the engine rating to alter performance or life cycle. There are many reasons why someone would want to do this. Every vessel is designed for a specific purpose and sometimes the vessel’s mission does not neatly fit into a range of standard options or offerings. For instance, if an operator wants a longer service life on the engine, and is willing to accept a reduction in power to receive that service life, the engine can be configured to provide that requirement.

Unintentional derating is a much more troubling scenario. When engines are rated, they are “certified” to provide a certain amount of power and torque for a specific period of time in a specific set of conditions. This is the fine print in the engine brochures and advertising that is usually not very prominent, or is sometimes even missing entirely.

Engines require adequate cooling in order to function properly. If an engine is rated at one level with ambient air temperature of 25 deg. C, using a specific fuel, what would happen if that engine was operating in an environment with an ambient air temperature of 40 deg. C?

The engine will not provide the same amount of power. It must work harder, and the result is a loss.

This is the frustration of the customer. He goes to an engine dealer, is assured of a specific level of power, yet received something else.

This is an area where MarineDiesel shines. Our VGT Series of engines features our own, programmable ECU. We can rate the engines according to climate, use, or customer specifications.

Since the majority of our sales are to military users, who normally must operate in a wide range of temperature extremes, our standard engine ratings assume far harsher conditions than the average customer is likely to experience. If that customer requires something different, it can usually be delivered quickly, and cheaply.

Some specific information about the VGT Series ratings:

Power Standards

The engine performance corresponds to ISO 3046 and a fuel with specific calorific value of 42,7 MJ/kg (18 360 BTU/lb) and a density of 0,84 kg/litre (7.01 lb/US gal, 8.42 lb/Imp gal).

The engines will operate up to 1000 m altitude and 40°C without derating. For operation at higher altitudes the power will be derated according to the following factors:
Altitude derating factor up to 3000 m 4% / 500 m
Altitude derating factor over 3000 m 6% / 500 m
Ambient temperature derating factor* 2% / 5°C
Humidity No derating
*Ambient air temperature at aircleaner inlet


Breaking In a New Engine



MarineDiesel engines are all built by hand, and thoroughly tested before any engine leaves the factory. Our quality control is unsurpassed. Every engine is operated for testing, and is in perfect working order when it is shipped.

However, all diesel engines, when new, require a “Break In” or “Run In” period before being pushed to their limits and operated under extreme conditions. The break in period for the VGT Series is 50 hours. Following this procedure will ensure a long, trouble free engine life.


The Marinediesel VGT series engines need break-in time before being operating to its full potential. This is due to the design characteristics of the base engine.

Follow the recommendations below:

0-5hrs: Use varied load and rpm but do not load the engine above 50% throttle and keep maximum rpm below 2500. Do not stay at one load and rpm configuration for more than 30 minutes at a time.

5-10hrs: Use varied load and rpm but do not load the engine above 60% throttle and keep maximum rpm below 2800. Do not stay at one load and rpm configuration for more than 30 minutes at a time.

Do an oil and filter change after the engine has run a total of 10hrs.

10-30hrs: Use varied load and rpm but do not load the engine above 80% throttle and keep maximum rpm below 3000. Do not stay at one load and rpm configuration for more than 30 minutes at a time.