For commercial vessel operators, reliability is everything. When an engine reaches the end of its recommended operational lifespan, shipowners must decide whether to replace it entirely or opt for a full refurbishment. However, not all overhauls are equal—different providers follow different approaches, and the extent of parts replaced can vary significantly. At Dpower, the focus is on quality, ensuring that every rebuild meets the highest standards to maximize operational reliability.
Marine diesel engines are built to run thousands of hours at sea, but eventually, they need to be refurbished. Generally speaking, a complete overhaul is required once an engine reaches 12,000 operational hours.
“After that point, we strip the entire engine down,” says Carl Rapp, Technical & Service Manager at Dpower. “Everything is measured, all worn parts are replaced—pistons, liners, bearings, seals. The engine block, cylinder heads, and major components are either replaced or fully restored to meet factory specifications.”
Once completed, the rebuilt engine is virtually indistinguishable from a new unit, ready for another 12,000-hour cycle.
“What remains is typically just the crankshaft and camshaft, provided they are within tolerance levels. There’s also some pipes, manifolds and so on that are usually kept, but we follow all of the recommendations of the manufacturer to the fullest extent,” Rapp says. “We pressure test and clean everything to make sure it’s in perfect working condition.”
Cost-effective—if done right
Choosing to renovate an engine over purchasing a new one offers significant cost savings. “It’s roughly half the price of a new engine,” Rapp explains. “Plus, some of these engines are out of production, so replacing them means reconfiguring the entire vessel, which can triple the overall cost. We can source every part needed for a rebuild. While a fully new engine built from spare parts would be prohibitively expensive, reusing certain core components makes it economically viable.”
Engine refurbishment is not a one-size-fits-all process. The extent of part replacements, the precision in measuring tolerances, and the thoroughness of testing all have a significant impact on an engine’s lifespan. At Dpower, every engine leaving the workshop is rigorously tested to ensure it can run another 12,000-hour cycle with full reliability.
“Some workshops make assumptions or skip crucial steps to save time and costs,” Rapp explains. “We take a different approach. The list of parts we replace as standard is extensive, and if there is any doubt about the condition of another component, we replace it too. Every step is meticulously documented, and when our clients see the full report, they are often surprised by the level of detail. We leave nothing to chance—ever.”
A growing part of Dpower’s business
Dpower’s workshop has grown steadily under the leadership of Carl Rapp, driven by increasing demand. To keep pace, the company hires new technicians every year. However, mastering the complexities of these engines takes time. To ensure knowledge transfer, DPower follows an apprentice-based system where younger technicians train under experienced staff – a strategy that has proven to be successful.
One of the company’s most seasoned experts is Peter Rosengren, who started his career as a technician at Gothenburg’s shipyards at just 15 years old. Now, at 63, he plays a key role in mentoring the next generation.
“The knowledge he brings is outstanding. My expertise lies in operating these engines over long periods, while Peter has been hands-on with them for decades. We started renovating these engines together years ago. Many of our younger technicians have also trained at the MAN Academy in Germany, and one of our youngest team members is already among the best. He has worked alongside Peter for years, learning directly from him. If needed, he could now complete a full refurbishment on his own.”
Expanding Capacity for the Future
With demand surging, Dpower is looking to expand. “Our biggest bottleneck is workshop space,” says Rapp. “We have the expertise and the workload to support a larger operation, but finding the right facility is proving to be a challenge. As soon as we secure a larger location, we’ll be able to scale up and take on even more work.”
With its focus on high-precision restoration, rigorous quality control, and an unmatched depth of experience, Dpower has become the go-to specialist for engine refurbishments for a wide range of engines.
Carl Rapp
Technical & Service Manager
carl.rapp@dpower.se
Phone +46 (0)31-748 62 08
