Richard Matthews speaks with Engebret Dahm, CEO of Klaveness Combination Carriers, about the rise, fall, and resurgence of tanker/dry-bulk “two-in-one” vessels. Once prominent between the 1970s and 1990s, these ships declined due to stricter safety and vetting standards following major incidents, cargo history limitations, higher complexity and capital costs, and poor economics in an era of low fuel prices.

Dahm outlines Klaveness’ journey and current fleet – 17 vessels, expanding to 19 across two core segments: CABU/Carbo ships, which transport liquid caustic soda in one direction and dry bulk cargoes on the return leg (notably Australia and Brazil), and CLEANBU designs, carrying clean petroleum products into the Americas before backhauling grains, sugar, and vegetable oils.

The conversation also covers operational complexities such as cargo switching and tank cleaning, early resistance from oil majors, and the broader, more diversified customer base seen today. Dahm highlights the high barriers to entry—from vessel design to crew expertise and systems—as well as the role of efficiency in decarbonisation, the limitations of current CII metrics, ongoing retrofit investments, alternative fuel flexibility, and the value of extending asset life through strong, customer-backed contracts.

00:53 What Is a Combination Carrier

01:53 Heyday and Decline

04:33 KCC Fleet and Origins

07:29 Trading Routes and Optimization

09:29 Operational Challenges and Vetting

14:49 Barriers to Entry and Know How

17:46 Efficiency and Decarbonization Edge

24:51 Alternative Fuels and Retrofits

30:00 Life Extension at 25 Years

35:16 Newbuild Plans and Market Timing