The friction between car tires and decks under ship motions

For roll-on/roll-off (RO/RO) ships, when transporting more cars within the same deck area on board, it is necessary to adjust or take away the current lashing system. Furthermore, this operation may also decrease the cost and time of operation as well as cargo damages due to lashing. This requirement, combined with the safety consideration on cargo shifting, may lead to concepts of lashing-free deck design. One of the lashing-free concepts suggests that in some conditions cars can be secured without using lashings, mainly depending on the friction between the tire and the deck without lashings. By doing a series of parametric studies of vehicle securing without lashings under roll and pitch motions, it was found that the value of the maximum required friction coefficient between the tires and the deck is highly relevant to the roll and pitch amplitude, pitch period, orientation of vehicles on decks, and the vertical location of vehicles from the baseline of the vessel.