The Scope
The Inpex Ichthys subsea trees (XTs) weigh 96t each and measure approx. 4.7m x 5.5m x 5.0m. The existing Upper Deck on the E5006 did not have sufficient structural strength to support the trees. Furthermore, the dedicated maintenance stands needed for inspection and maintenance activities offshore prior to running neither had the required strength or stability to support the XTs during transit & cyclonic conditions.
The Outcome
Cube Offshore successfully designed two “integrated” structural support grillages which maximised the use of existing underdeck steel on the E5006 to minimise the weight of the new support stand. The new support stands supported the XTs 1.6m above deck to allow for inspection & maintenance activities prior to being run subsea. The stands are strong enough to resist cyclonic and transit loading with the XTs on top thereby avoiding further tie-down or handling requirements. The corner posts are bolted onto the support frames allowing removal for alternative laydown options offshore.
