Don’t Play Games With Your Wear Part Planning

Board game for wear part manufacturing planning
Board game for wear part manufacturing planning

Last week we had another of our training courses for service engineers and field service engineers1. The interaction with people actually working with our products is quite refreshing and every time I understand their issues better. One of those issues is that they have to discuss with the client are spares for the wear parts. In a planned maintenance context, wear parts are a little odd. Sometimes, they are worn away or break down unexpectedly. And that is the moment customers call for spares. We do have a lot of spares on stock, but sometimes even we run out of stock or we advise to use a special execution of the concerned part for the specific operation of the client. And then we have to inform the service people and the client that there is a long lead time. Several times, they are filled with disbelief and under such circumstances it is very difficult to explain the reasons behind it. So, that is why I developed this little game to experience the waiting time for special wear parts.

Layout of the board for the wear part game
Layout of the board for the wear part game (Download pdf version here)

It is based on the old board game of ‘Snakes and Ladders’2. All it takes are the board, one dice and as much tokens as players. All start at the first position. The places are all phases in the manufacturing of the wear parts and each have their specific issues.

  1. Each pattern is used multiple times and wears down, itself. Also, some patterns have to be configured for the specific application, execution or material of the wear part.
  2. Moulding: the pattern is placed in a casting box and filled with sand.
  3. Sometimes there are more casting boxes needed and they have to be stacked carefully. Depending on the configuration, this step might be very short. Then you go directly from 2 to 4.
  4. Part of the casting system is already in the sand box with the pattern, but it has to be finished as the last part of the preparation.
  5. The material is melted in the furnace. This can take some time, depending on the size of the cast.
  6. The actual casting is done in minutes. Fifteen, at the most.
  7. But the cooling in the casting box takes weeks. Wait one turn.
  8. Sometimes the casting has not gone properly and the cast have to be done again. Back to square one.
  9. Satisfied with the cast, then it has to be touched up at the fettling station.
  10. A special heat treatment brings the final hardness and toughness to the product.
  11. The fitting surfaces of the wear parts have to be machined.
  12. Rotating parts have to be balanced. For non-rotating parts, this can be skipped.
  13. Then there is the bottle neck: quality control. If there is a deviation that can n ot be mitigated, you have to go back to square one.
  14. Depending on the location, transport can take weeks.
  15. Don’t start me about customs handling. Your anticipated spares are in bonded storage and customs is missing a document, wait some weeks or skip a turn.
  16. Finally, you’ve made it! Installation on the dredge.

Message of the game: keep your warehouse well stocked with wear parts3,4, or your dredge will be idle for months, before you can work again. Have fun!

Spare parts on stock
Spare parts on stock


  1. A well-trained team makes all the difference, Damen
  2. Snakes and Ladders, Wikipedia
  3. Do You Have Wear Parts For Spare?, Discover Dredging
  4. Options for Repairing Parts That Ought to be Replaced, Discover Dredging

See also

How DOP Pumps Developed and Entered the Digital Age

First application of a DOP pump

Recently, my daughter asked me: ‘Dad, what good is it to know your history?’ And I answered: ‘Dear, if you don’t know your past, you will not understand the world around you.’ And the world around us is changing rapidly. The most recent change in our dredging world is the launch of the DOP web shop1. The ultimate entrance into the digital age of a well proven pump. For those young people that only know how to order online (or others interested in dredging history): long before webshops were around, customers and suppliers had a direct relationship with each other.

In the early ‘90s, when Ballast Nedam received the contract to build the railway tunnel near Schiphol Airport2, they had a real tough challenge. The ground water level near Schiphol is very high. Any hole there, fills up rapidly. Using sump pumps to remove the water from a building pit would be useless. To prevent collapse of the sides, there was already sheet piling in place, supported by braces to carry the side load. The space between the braces was too small for a long reach excavator. And the area under the braces too low to work from pontoons. Moreover, the foundation pilings where already in place and they should not get damaged by the excavation with a crab crane.

Construction site of the railway tunnel at Schiphol Airport

At this point, Ballast Nedam contacted their supplier De Groot Nijkerk for a smart solution. Ballast Nedam wanted a small self-contained dredging machine, that would fit between the braces and remove the sediment hydraulically. In a real Gyro Gearloose fashion, De Groot Nijkerk managed to patch together a contraption to prove the concept: ‘the first DOP pump’ (of some sort). It consisted of a normal dredge pump and a submerged jet pump in the same frame.

Proof of concept for a DOP

The tests were successful and the prototype was turned into a production model. The main difference being that the bearing and the dredge pump were designed with a mechanical seal to remove the gland water installation. This mechanical seal required some development on itself, as standard mechanical seals were too fragile. The newly developed seal was of real dredging proof quality. The product was successfully used and word spread around the Dutch contractors about this nifty little dredging machine. As a result, the new DOP was introduced in 1991 and started a career of its own.

Introduction of the first standard DOP on the market

As customers were very original in creating their own solutions for their specific problems, this single product slowly evolved in a whole line of products and options3. For as long as I remember, there was this picture in the product leaflets, that the customer could use to configure their own tool. Hence the slogan: ‘Your job, our tools.’

Typical selection diagram of DOP options

Over time, the range has been reengineered and thoroughly standardised. Due to this standardisation, the sales could also be standardised. Thus, the natural consequence: the webshop. Here you can experience online convenience with personal service.

Real DOP’s on display. Buy them at


  1. Damen DOP shop
  2. Schiphol Airport expansion, Wikipedia (Dutch)
  3. The DOP® submersible dredge pump and the possibilities for the contractor, DPC December 1998

See also