In the past few months, DNV has received an increasing number of requests to evaluate the hatch cover strength for helicopter landings, mainly from bulk carrier operators calling at Australian bulk terminals.
A number of major Australian ports are using helicopters to transfer marine pilots. The Australian Maritime Safety Authority (AMSA) is therefore requesting proof from the ship’s master that the hatch covers are strong enough to withstand the helicopter loads.
To support the owners, DNV has started evaluating the strength of hatch covers based on the Rules for Ships Pt.6 Ch.1 Sec.2 – Helicopter Installations.
This evaluation is normally done for a specific helicopter type. EUROCOPTER-145 and BELL 430 are the most commonly used.
Based on the hatch cover scantlings, we are also able to calculate the maximum helicopter take-off mass for both helicopters with wheel landing gear and helicopters with tubular skids. The results are more favourable for helicopters with wheel landing gear. (The same hatch cover will be able to withstand a higher take-off mass in the case of a helicopter with wheels than one with skids.)
A statement has been issued upon completion of the strength assessment of the hatch cover.
In most cases, the results hatch cover strength assessment are positive. Most of the hatch covers will be able to take the load of a commonly used helicopter provided the hatch covers are well maintained and there is no significant reduction in the as-built thicknesses.