SOLAS is based on the notion that a ship shall be self-sufficient and independent of external support in case of an accident. In a special category of ferries, High-Speed Craft (HSC), typically constructed from lightweight materials like aluminium, have been safety-regulated in a different way than steel ships because, with their reduced weight, they would not be able to carry everything needed to be autonomous. The higher operating speeds were also perceived to introduce new risks. The year 2000 HSC Code therefore focuses mainly on passenger evacuation/rescue and the different fire risks, in conjunction with shore-based support. To distinguish this novel safety approach, the HSC Code requires such vessels to have a minimum design speed – typically 30-40 knots depending on their length.

Historically, HSC have served markets demanding quick crossings, so the minimum speed requirement has not been an issue. However, more recently there have been ever-increasing demands for greater energy efficiency and lower greenhouse gas (GHG) emissions, where slower speed as well as lighter weight are important factors. As such, at a time when the IMO is legislating for dramatic CO2 reductions – and when many operators have reduced speed to cut costs – it goes against all common sense for the Code to enforce a level of engine power appropriate only for fast running during sea trials.


Interferry believes that engine power should not be regulated unless justified for safety considerations. In 2019 the association established an industry consortium with HSC manufacturers Austal and Incat, and classification society DNV. A study commissioned from Seaspeed Marine Consulting reviewed the HSC Code and identified any implications of removing or adjusting the current minimum speed requirement.

The plan was to submit a speed revision proposal to the IMO during 2020, but the pandemic has caused all new issues to be deferred until 2022. Regardless of the IMO’s general scheduling of revisions, we could anyway not expect our proposal to enter into force until the next SOLAS revision in 2028, although individual Flag States would likely issue exceptions far sooner if the ongoing IMO work indicated support.

In addition to the speed issue, the IMO’s Carbon Intensity Indicator (CII) initiative is a particular concern for HSC. Following the Marine Environment Protection Committee meeting last June (MEPC 76), a correspondence group including Interferry was set up to consider various outstanding details on GHG emissions by the end of August – not least how to ensure a fair CII dataset for HSC. The current formulae severely disadvantage HSC because there is no distinction between them and conventional ro-pax vessels. Interferry is asking the IMO to separate the sub-segments so that each is treated fairly.

Defining the efficiency of ferries is already highly complex due to their diversity, and mixing up two distinctly different ship types makes fair treatment impossible. HSC are typically less energy efficient than conventional ro-pax if transporting trailers and cars. However, if efficiency is measured as fuel consumed per passenger per mile – as in aviation – HSC is on par with conventional ro-pax.


We all recognise the imperative to move on from a fossil world, and are happy to contribute, but we must avoid a statistical method that is not firmly anchored in reality. Before our IMO submission is discussed next October, we will reach out to relevant Flag States to affirm their support of the concept. In addition, while the issue is purely environmental, procedurally we have to voice our concerns with the Maritime Safety Committee, the guardian of the HSC Code. To that end, we need to engage more widely, even with Flag States who have no inherent interest in HSC.

Reference: SeaSpeed Marine HSC Code White Paper (SMC 560/02 Issue 01, July 2021)