-- FROM THE FULL PICTURE MAGAZINE --
Engine monitoring systems are not new, but they may now be making their
way onto ships in a big way. The greater control and oversight they offer are attractive
propositions. Even better is the possibility of skipping a risky open-up and inspection.
Strictly speaking, German shipowner D. Oltmann Reederei did not need to install
engine monitoring systems in its three container ship newbuildings under construction
at Hyundai Heavy Industries (HHI). Oltmann, like just about every other shipowner,
had never installed the components before, so why start now?
"As a shipowner, we are not likely to change unless there is a benefit, an incident,
or both," says Joern Winter, Managing Partner and Director for Fleet Management
and Operations at D. Oltmann Reederei in Bremen.
"In this case, there is a clear benefit; with engine monitoring systems, we may
be able to forgo the open-up bearing inspection often required by class after five
years. And, although we have had no engine failures, we're interested in savings
related to extra service calls and inspections."
The designer of the low-speed diesel engines being installed in Oltmann's newbuildings,
MAN Diesel, recommends these sensors, but they were not made standard equipment
until recently. The systems have become necessary due to the higher power to weight
ratio of today's engines, and new metals designed to handle these forces.
MAN Diesel's project guide book for the low-speed diesel engines being installed
in Oltmann's ships states: "The ultimate protection against severe bearing damage
and the optimum way of providing early warning, is a combined bearing wear and temperature
monitoring system." It was the first engine designer to make engine monitoring systems
standard equipment, and is thus an early mover on condition-based maintenance.
Dodging a bullet
Bearing wear monitoring Measures and displays the combined physical wear of crosshead, crank and main bearings, providing early bearing seizure warnings if problems occur during engine operation.
Cylinder liner monitoring Monitors piston running performance by measuring the temperature of the upper part of the cylinder liners. Increased friction can lead to abnormal liner wear and potential piston ring breakage.
Main bearing temperature Mounted on the main bearing girder with the tip of the sensor in direct contact with the bearing shell, it measures the combined temperatures of the bearing shell and lubrication oil.
Water in oil sensor/detector Dual sensors give continuous measurement of moisture in oil and oil temperature. Moisture in oil is measured in terms of the water activity and temperature, independent of oil type and age.
Crosshead & crank bearing monitoring Continuously measures the metal temperature of bearings during engine operation. The sensor communicates with a processing unit using a high frequency and low energy radar pulse, thus giving the temperature of moving bearings.
Data compiled by Swedish Club surveys illustrate damage causes and costs on low-speed
engines. Of the five most frequent types of claim, cylinder liner and bearing damages
come in at three and four, respectively. In terms of average cost, however, they
are the most expensive claims. Thus the downside of a failure provides strong motivation
for an engine monitoring system.
Describing Oltmann's motivation, Winter said: "We want increased and improved
insight, and a safety margin to react to new requirements. Monitoring is the key
to success in terms of efficiency and increased control. Safety and savings are
vital to us."
Oltmann originally approached the licensed engine manufacturers at HHI about
engine monitoring systems. From there, contact was made to Kongsberg Maritime, which
produces a range of sensors for engine monitoring and which was already supplying
the ships' propulsion control systems. Arjan Paans of Kongsberg Maritime met with
Oltmann in 2008.
"For low-speed engines, a number of monitoring systems are recommended," says
Paans. "These include temperature monitoring of crosshead, crank and main bearings,
bearing wear monitoring, cylinder liner temperature monitoring and water-in-oil
sensors. We expect all of these to become standard equipment soon."
Four core systems
Oltmann's three container ships will each possess a package of engine monitoring
systems, which – in addition to a pressure analyzer and the conventional oil mist
detection system – result in what Paans has called "one of the best equipped engines
in the world today."
Kongsberg's bearing wear sensor was developed in close co-operation with MAN
Diesel, and is designed to provide the crew with early warning if any of the crank
train bearings have an unexpected wear rate. Basically, a sensor will measure the
combined wear of the main bearing, the crosshead and crank bearings at bottom dead
center, and trigger an alarm if a problem is developing.
The bearing temperature sensors track metal temperatures in the three bearings.
The crosshead and crank head temperature sensors operate wirelessly. The sensor
itself has no power demand, and its signals pass via low-energy radar technology.
The cylinder liner monitoring system measures the temperature of the upper part
of the cylinder liners. Increased temperatures set off an alarm, so that the crew
can respond before excessive scuffing occurs. "Many shipowners have experienced
problems of this kind, and they're very interested in avoiding the high costs associated
with reconditioning or replacing the cylinder liners," says Paans.
The water-in-oil sensor has earned extra emphasis from engine designers. Water
content reduces lubrication, which can cause cavitation and corrosion. Corrosion
will result in fatal engine damage very rapidly. "We believe the water-in-oil sensors
are a significant improvement on the oil mist detectors," said Winter. These systems
fulfil the same functions as today's oil mist detectors, but are quicker and more
All of these systems are connected to Kongsberg's AutoChief C20® system via the
common (CAN) network. Any failure can have two results: either it will trip off
an alarm, or automatically initiate slow-down.
"It's important to understand that these systems can also be used for condition
based maintenance, which is getting more and more popular among shipowners," says
Many shipowners want to invest in these systems to skip the kinds of open-up
inspections of main engines required by classification societies today. Approximately
70 per cent of bearing seizures occur shortly after an overhaul or open-up inspection.
This is simply because conditions during the open-up, and the personnel doing it,
are seldom as good as during the engine's production.
"If we can extend the amount of time between open-up inspections, we stand to
save a lot of money. This is a very valuable argument for us," says Winter.
He also argues that the systems will provide Oltmann with an advantage on its
competitors in terms of reliability, when negotiating with charterers. He continues:
"Charterers have different values when it comes to the ship's operations, but many
of them aren't interested in your technical issues. Some may choose us partly because
we have well-equipped ships; others aren't as interested. But everyone wants reliability,
and that's what we aim to offer."
Asked why Oltmann chose Kongsberg to supply the engine monitoring systems (MAN
Diesel recommends a handful of suppliers), Winter explained that the company's prior
experience with Kongsberg played a big role.
"As a private shipowner, we need to make money on existing vessels, if we want
to extend our fleet. Thus we're looking for synergies," says Winter. "If we can
combine service calls with one maker, we save money. Also, as a tramp owner, we
need to have a global partner, because we don't decide where the ships will be calling."
Inevitable and invaluable
Oltmann is one of a host of shipping companies that is investing in these kinds
of systems (Denmark's TORM is putting them on a series of 11 ships), or seriously
considering them. The engine manufacturers recommend the systems, classification
societies approve them and providers like Kongsberg are steadily improving them.
Said Winter: "These have become much more reliable and reasonably priced. Five to
ten years ago, this was very fancy kit. Costs have come down and quality has gone
up." There is also a manpower and skills side to the picture. Seagoing personnel
frequently have less experience than before, and engines are only getting more complex;
given the situation, a more intensive alarms strategy mitigates operational risks
"These sensors will result in alarms and/or an automatic response that prevents
damage before it happens," said Paans. "This can save you an expensive repair and
possible off-hire, at the very least; at the most, it can save your crankshaft."