The Right Tools For The Job – Avoiding Dangerous Shortcuts

In this article we will look at a specific incident involving a grinding disc that breaks up during use reported in the UK Marine Accident Investigation Branch (MAIB) Safety Digest 1/2017. Although the report is specific to a grinding disc incident the lessons learned are relevant to many accidents or near misses experienced on board.

The incident involved a grinding disc which disintegrated and penetrated a protective safety mask and caused an injury to the second engineer. He was lucky that his injuries were not more serious.

What Happened?

The engineers on a large container vessel were overhauling a slow speed 2- stroke main engine cylinder liner and piston. The first part of this process was to safely remove the cylinder head and piston. The next step was to calibrate the liner which involved taking measurements to determine the amount of wear to the liner.

Before calibrating the liner and before putting a new piston into the engine it is important to remove the wear ridge. A wear ridge is formed at the point where the piston rings do not reach, towards the top of liner. Most engine makers will recommend that the ridge is removed at every overhaul. Therefore the correct tools for the job should always be kept on board.

The second engineer realised very quickly that the grinding disc normally used for this task was worn too much.

On searching the second engineer found another disc to use but the hole was larger. Having nothing more suitable to hand and wishing to progress the maintenance he fabricated a washer to allow use of the disc with the larger hole.

The second engineer then entered the liner to remove the ridge. As soon as grinding started the disc shattered. One piece smashed through his mask hitting his head above his left eye. This was enough for him to lose consciousness and he needed to be lifted out of the liner.

Why Corners Are Cut And What Are The Reasons Behind This?

• There may have been time pressure to complete the main engine piston overhaul within a certain time frame and allow the vessel to depart on time. Pressure is placed on crew to complete work in time and prevent delays to the vessel departure. Time is money and commercial pressure can be high. The shortcut in this instance was to use another type of grinding disc not fit for purpose.
• The second engineer may have only realised that the grinding wheel was worn too much just before he started the grinding job on the ridge. This may have left very little time to find the correct tools.
• The grinding disc which was used unsafely may have been the only available grinding disc at the time.
• He may not have been aware of the speed rating of the new grinding disc in relation to the speed rating of the grinder. The grinder used had a maximum speed rating of 22,000 RPM, but there was nothing to suggest that the grinding disc used was rated above 15,000 RPM.
• There was no washer used normally with this grinder but the second engineer may have thought this was the quickest way to get the job done without considering the consequences.
• He may have used the protective mask because it was the only type available on board or he thought that it was suitable for grinding. But the mask may only be suitable for chemical protection.
• Human nature. Crew will always be tempted to look for the easiest answer to a problem. But this may not be the most efficient. Time, effort and most importantly safety may be compromised if shortcuts are taken.

What Lessons Can Be Learned?

• The correct equipment should always be used for the task in hand. In the above example the correctly rated grinding disc and protective mask should have been used for this work and available. This applies to all tools and equipment on board a vessel because using the wrong equipment may be dangerous. If you’re unsure of a tool’s suitability for the job then don’t do the job until checks can be made. Always carry out a risk assessment.
• It is important to educate the crew about the dangers of shortcuts. This may require further guidance from the ship management office.
•  Ensuring crew understand the importance of equipment rating and correct usage. Planning is essential! If maintenance is planned then are tools and equipment present and correct to complete the job? If there is a shortfall then ordering may be required in advance of work. Safety should not be compromised because of missing equipment.
• Crew should ensure that personal protection equipment is suitable for the work they are undertaking. For example masks to prevent chemical damage to eyes may not be enough to prevent objects with a high momentum.

With thanks to Queensland Government for permission to use images 1-3.