In the case of the marine department, most replacement parts have to be bought through a specific manufacturer. This manufac- turer or official retailer is then in a position of power and can dictate the price in the market since it is unusual for ships to change engineering systems mid-life. The only strategy is to change man- ufacturer in new build projects. This, however, has also its disad- vantages since the personnel needs to be retrained and economies of scope are lost. A common strategy is to build ships in classes where a run of 3–6 identical ships will be built in order to facilitate personnel movement and curb training costs.