Green Marine can carry out transit and towing analysis to investigate vessel or device behaviour during transportation or transit. The focus of these analyses is to specify towing equipment and any seafastenings required. If a renewable device or sensitive equipment is being towed, an analysis can show the motions and accelerations the object is likely to experience during the tow.
A key stage of Project Natick was the towage of the device and installation barge from the assembly location to the deployment site. The decision was made to have the load suspended from the GM700 installation gantry barge to remove the need to transfer the device from a flattop barge to the lifting barge on site. Green Marine carried out a transportation assessment to establish could this be performed without the addition of seafastenings (1), to quantify dynamic loading on the device & rigging (2) as well as its excursions relative to the barge (3).
The engineering team used Orcaflex to model the barge and device under tow in a number of environmental conditions. The device was submerged over a range of depths during this assessment to find the optimal position for reducing loading & relative excursions.
From the results of this analysis, the lift rigging was specified, weather limits were set and the optimal draft of the device was found.