Mechanism and Dynamics of Marine Ice Accretion on Vessel Archetypes

Abstract

Abstract Marine icing (or, 'sea spray icing') is a well-known threat for commercialfishing craft and other relatively small vessels. However, larger vessels, suchas supply ships, where localized icing can primarily be a safety or operationalhazard, are less well studied. The MARICE project is a multi-year effort by DetNorske Veritas (DNV), the Norwegian University of Science and Technology(NTNU), Statoil and the Research Council of Norway (NFR) to study this issue. Athree-part simulation system has been designed to study the amount of waterlifted from different types of ship bows in different weather conditions andestimation of the movement of droplets over, and their impingement with, thesuperstructure of vessels, neglecting the possibility of droplet break-up orcoalescence. It was found that areas where the icing potential might be thegreatest are not necessarily intuitive, as the movement of water and air isturbulent. Attempts were made to validate the model for water freezing on ametal unit against land-based spraying measurements conducted on Svalbard innatural weather conditions. The results of this study would be of greatestinterest in the design and operation of vessels for cold conditions where seaspray icing might pose a hazard. 1. Introduction Due to the increasing interest in commercial operations in cold marineenvironments, the process and dynamics of sea spray-generated ice accretion onmoving vessels is a high priority area of research. For smaller vessels, suchas many commercial fishing boats, the general threat posed by spray-generatedicing to the stability of the craft is widely acknowledged. However for vesselssuch as those in the 100-meter (300-foot) length range, where the rightingability is less likely to be compromised, the primary concerns regarding vesselicing are more localized, specifically interference with normal operations dueto hindrance of the motion or functionality of equipment, loss of equipmentaccess and obstruction of walkways, icing of sensors, work burden associatedwith ice removal, threat to the safety of the working environment and abilityto conduct emergency operations.