Ballast-free ships – will they happen?

Malcolm Latarche
Malcolm Latarche

08 December 2017


This week at Marintec China, LNG containment specialist GTT and Dalian Shipbuilding Industry Co (DSIC) received approval in principle (AiP) from Lloyd’s Register (LR) for their 30,000m³ B-FREE LNG carrier design. Ever since the issue of species transfer by ballast water was first raised, there have been regular attempts to develop a ballast free or minimum ballast ship. To date none of these have come to fruition or industry wide acceptance. While the initial driving factor behind developing a ballast-free ship was to prevent any opportunity for species transfer, more recently the cost of installing and operating a ballast treatment system has been advanced as a good enough reason. The announcement of the AiP for the design used these reasons as well as some others including not having to comply with the Performance Standard for Protective Coatings (PSPC) for ballast tanks. These are all valid reasons, but it seems that few if any owners have yet found them compelling enough to opt for a ballast-free ship. What the announcement did not reveal was the precise means by which the ship would not require ballast tanks. Ma Yingbin, Vice Chief Engineer, DSIC, is quoted in the statement as saying “While we are still in the initial stage of the project and the design is subject to ongoing change, the initial results are indicating that we will meet our goal of having a ballast-free ship that is equal to, or better than existing conventional designs. The ship granted AiP was a 30,000m3 LNG carrier – a small ship by the standards of most LNG carriers and therefore likely intended for coastal or short sea distribution or even as a bunker barge. There are very few ships of similar size so comparisons are limited. It may be that if same risks areas were established in time before the ship was ever built and it was intended for such limited operations, then a ballast treatment system would not be necessary in any case although the PSPC requirements would still apply. Previous designs of ballast-free vessel have covered several ship types. At least one concept intended to make use of flow-through ballast systems whereby the ballast water was constantly being replaced as the ship moved through the water and taking in new ballast at the bow and discharging the older ballast at the stern. Another concept was a pronounced vee-shaped hull coupled with a wider beam that would allow for a similar displacement by length but without needing ballast. A true ballast-free ship would arguably need some form of anti-heeling system to replace the ability to move ballast to correct trim or list for operational purposes although this would probably not be enough to allow for extreme lists to be deliberately introduced so as to avoid water ingress if the hull was damaged in some way. LR says that the first results show that this ballast-free design has also introduced complimentary advantages such as a reduction in the number of cargo tanks, handling equipment, engine power, and more. We are excited to move forward with the next phase.” It will be interesting to see how the project does evolve and if the benefits are as positive as they are claimed to be, then doubtless several owners of other ship types will be watching to see if the ballast-free element of the design can be applied to other ship types. That could reduce the cost of newbuildings and be another blow for makers of ballast treatment systems on top of the recent decision to effectively delay enforcement of the initial installation dates.