Question 62 OSV02 - Mate - Offshore Supply Vessels

The Correct Answer is D **Why Option D ("Five to seven times the depth of water") is correct:** The recommended scope of anchor chain (the ratio of the length of chain paid out to the depth of water plus the height of the bow above the water—known as the vertical distance to the hawsepipe) for anchoring a vessel under normal conditions (good holding ground, moderate weather) is generally between 5:1 and 7:1. * **Optimal Holding Power:** A scope of 5:1 or greater ensures that the anchor chain forms a relatively shallow angle with the seabed. This horizontal pull is crucial for maximizing the holding power of the anchor, as it prevents the anchor fluke from lifting out of the ground. * **Safety Margin:** A 7:1 scope is often used in situations requiring higher security, such as exposed anchorages or when anticipating stronger winds, providing an excellent margin of safety. **Why the other options are incorrect:** * **A) Two and one-half times the depth of water:** A 2.5:1 scope (or even 3:1) is considered a "short stay" or temporary anchor setting used only for brief stops in extremely calm conditions, or while waiting to moor. It provides insufficient holding power and is highly likely to cause the anchor to drag if wind or current increases. * **B) Fifteen times the depth of water:** A 15:1 scope is far excessive for normal anchoring. While theoretically increasing holding power slightly, it is highly impractical. It wastes valuable chain, takes up an unnecessarily large swinging circle (creating collision hazards), and makes weighing anchor much more time-consuming. * **C) Four times the depth of water:** A 4:1 scope is considered a minimum safe scope in ideal conditions (very calm weather, known excellent holding ground). However, it offers a small safety margin and is typically not the *recommended* scope for general "normal conditions," where a 5:1 or 7:1 ratio is preferred for reliability and safety.