Non Conventional Propulsion For Ships Operating in Dangerous Atmospheres (Air Indipendent Propulsion)

On behalf of AgipKCO, Navalprogetti has designed an Air Independent Propulsion system to be installed on the shallow water icebreaking tug “Mangystau”.


The target was to install a removable storage system to provide the vessel with a source of energy that will allow to operate for 30 min in a contaminated atmosphere, in particular with H2S release, where diesel propulsion could not be utilized, through a 60 cm first year ice with a speed of 2 kn.

The first phase of the project was concluded in October 2011.  Here, the philosophy of the system was identified and described. In the second phase, a detailed description of the identified solution was  presented in collaboration with the potential suppliers of the necessary components and equipment.  The proposed innovative system, will allow the vessel to operate by means of the already installed propulsion system, independently of the external atmosphere in a gas release situation and will guarantee “safe living conditions” inside the recovery area for 68 persons for 2 hours.

The vessel will be provided with a source of energy that will allow sailing for 30 minutes in a toxic gas cloud through 60 cm first year ice (flexural strength 500kPa), in shallow water, with a speed of 2 knots.

The necessary energy for propulsion will be stored in lithium-ion batteries arranged in 3 ISO40 containers installed on the Main deck as dismountable installation.

In particular, in the second phase, the following key issues have been considered:

  • Battery type and arrangement has been identified with the contribution of a potential supplier .
  • The battery system hazard and risk analysis has been presented.
  • The power conversion system and its interface with the existing equipment has been defined with the contribution of a potential supplier.
  • The container characteristics and the inside arrangement has been defined. The position of the containers on the vessel’s main deck and the basements for the connection to the existing structure has been studied and a strength check carried out.
  • The cable watertight and gastight passages have been defined, as well as the removable protection structure.
  • The air system for the recovery area has been defined, including the definition of the container for air bottles, compressors and dryers. A potential supplier has been contacted and a quotation of the air system has been received.
  • The fire fighting system has been verified to be in compliance with current rules even after additional equipment installation

mangystau GA