Lashings should be spanner tight. Slack lashings on container bays are not desirable for obvious reasons. But should the crew apply excessive force or use tools to increase the mechanical advantage on the lever that allow them to over-tighten the lashings?
The answer is no. Overtightening can result in the lashing rods coming under excessive strain which can increase the pre-tension by a few tonnes leading to their failure when under load. Stevedores and crew should only spanner tight the lashings. Caution statements highlighting this must be included in the Cargo Securing Manual (CSM) which should be prepared in accordance with the guidelines inMSC.1/Circ.1353/Rev.1, Ch.4.
There are several other factors which should be kept in mind such as
It is strongly recommended that the lashing software used onboard is integrated with the loading be stability software.
Loss Prevention poster Lashing equipment