FINAL HEADING
The final heading is the direction in which a ship will lie when at anchor heading into the wind and current acting on her superstructure and underwater hull, after the anchor has fetched up and the ship has swung around to bring all those forces into play. There are several reasons why it's better to let go when the ship is on her final heading, and the advantages of doing so more than compensate for any additional time spent maneuvering to that heading. When the anchor is let go on the final heading:
1. The chain will lead clear of the hull as it's slacked out.
2. Wear and strain on the chain, stem, windlass, and the mate's paint budget are minimized.
3. The chain is laid out along the bottom neatly and quickly.
4. The ship can be positioned among other ships and obstructions without concern about swinging clear after the anchor fetches up since your vessel is already on the same heading as those ships.
The more restricted or crowded the anchorage, or the stronger the wind or current, the more important it is to anchor on this heading. In some instances it is essential to anchor on the preferred heading. Large bulbous bows can be damaged by a chain leading under and around the bulb with a heavy strain and, even more importantly, the chain itself may be damaged.
Heavy winds, swell, and strong currents can be a problem as the chain works and surges more heavily against the wildcat, and the stem, bulb, and any protruding ship's gear. It isn't always possible to maneuver to this final heading before letting go, especially when the anchorage is small or crowded, or the wind or current is quite strong or from the wrong direction, or visibility is restricted. It isn't always necessary to do so either, since a ship may anchor on any heading in light airs or slack water; in a calm, every ship in the anchorage probably lies at a different heading anyway. A real professional, tries to bring the ship to her final heading before letting go in even a light breeze or weak current and, in practice, a reasonably skilled ship handler is usually successful in doing so.
How is the final heading determined, look at other ships and boats anchored in the area that are already lying to the wind and current or estimate the heading if there are no ships in an anchorage. A master could also compute the final heading by vector analysis, but the calculation would be complicated and impractical in day-to-day work, and there would be no point in doing so when such information is not needed anyway. A practiced seaman's eye, current tables, the knowledge that a 1-knot current has approximately the same effect as a 30-knot wind over a given surface area, and some seafaring experience are really all that are needed to determine this heading with reasonable accuracy.
