There is no new thing under the sun
The problem of anchoring in a designated spot usually involves only the placing of the bow of a ship over the required location and the dropping of the anchor when the bow is in Position. Normally this is a simple exercise in seamanship and navigation. The captain of one of the large battleships, or one of the plane carriers, in a ship of 33,000 tons with a draft of 32-34 feet has another factor to consider whenever he attempts to anchor in an assigned berth. Like every other ship captain, he must put the bow of his ship over the designated spot and let go the anchor when the bow is in the correct position, and, in addition, he must so regulate his approach to the anchorage that his ship will be practically "dead in the water" when the anchor is dropped. It is imperative that the commanding officer of one of these large ships know the exact distance and course at all times if he is to so regulate his approach as to reach his position in the desired manner. The problem, then, becomes one of plotting instantaneous bearings so that the position of the ship is definitely known at all times during the approach.