There are some issues with this approach which make them vulnerable to damage or loss on a project and these all must be risk assessed and mitigated. Since nodes connected together on a rope sit on the sea floor unattended: they can be moved due to strong currents, the ropes can snag on seabed obstructions, they can be dragged by third party vessel anchors and caught by trawling fishing vessels. The threat of these types of potential hazards to this equipment should normally be identified and assessed during the project planning phase, especially in oilfield locations where well heads, pipelines and other subsea structures exist and where any contact with these must be avoided, normally achieved by adopting exclusion zones. Since it is possible for node lines to be moved after deployment, the issue of node position on recovery is critical and therefore positioning during both deployment and recovery is a standard navigation quality control check. In some case, node lines may need to be recovered and re-laid if the nodes have moved outside of the contract specifications.
