What do frapping lines do?

Fraping lines serve the specific function of holding the lifeboat securely alongside the ship while it is being prepared for launch or during operations. These lines help ensure stability and prevent the lifeboat from drifting away from the vessel, which is crucial for the safety of embarking and disembarking procedures. By keeping the lifeboat in position, crew members can effectively manage the transfer of individuals or goods without the risk of the boat moving unexpectedly.

While other options touch on important aspects of lifeboat operations, they do not accurately describe the purpose of frapping lines. For example, securing a lifeboat's cargo is more aligned with the use of additional securing lines rather than frapping lines themselves. Safety tethers for passengers are crucial for keeping individuals secure while onboard the lifeboat, but that is a different safety measure. Meanwhile, the deployment of a lifeboat during emergencies involves other mechanisms such as davit systems or releasing hooks, rather than the frapping lines. Thus, the primary and correct role of frapping lines is to hold the lifeboat alongside the ship during various operational situations.