Anchor Spirits

Introduction
Throughout nautical history, the most worn sailors have often taken on the habit of referring to a ship as though it was an entity, as though it had a soul and a voice of its own. Are they merely delusional from decades spent under the wear of salty waves, or are they simply more in tune with the spiritual side of the ocean?

History
Many ships bear details that lend it a semblance of humanity, such as figureheads or eyes painted on the side. In most such cases, these simply served as decoration. But in a few cases, when the ships they were a part of had come perilously close to being claimed by the briney depths, the intensity of the moment, combined with the desperation of the sailors and the hope symbolized by the artistic details of the ship itself would cause something to awaken.
These entities, normally only known to the captain of the ship, are the spirits of the very ships themselves. Possessed of an intrinsic love of the ocean and almost biological control of the functions of the ship, they can give the ship the extra bit of 'oomph' needed to escape a whirlpool, the stability to avoid being capsized, and even the luck that could cause an entire rack of harpoons to clatter loudly to the deck when the ship is being stealthily boarded in the dead of night.

Personality & Abilities
The exact abilities of an anchor spirit are as varied as ships themselves, and often closely reflect the personality of the spirit. A blockade runner might posses a feisty spirit that thrills at the thought of danger, while a fishing schooner might be inhabited by a patient yet strong spirit.
In general, most spirits share some abilities. As previously stated, they have almost biological control over the ship. They can cause knots in rope to appear or disappear, manipulate the state of the sails and cause almost poltergeist-like activity. These things are almost never done if the spirit believes it would hinder the ship or its crew, but instead would cause a tangled rope holding the sails in to come loose or toss a bucket of water onto a fallen torch.
Most Anchor Spirits communicate only with the current captain of the vessel, though who they deem captain isn't always the man in charge of the ship. To such a person, they often appear similar to a ghost, but with less of a frightening aura. Their appearances vary as much as appearances do among people, but they always have some sort of aquatic trait. This can range from something minor, such as long, flowing hair that billows as though it were underwater, to a very defining characteristic, such as having the face of an angler fish. Generally their appearances fit their personalities. A pirate vessel's spirit may have needle like teeth, a beard of barnacle encrusted seaweed and a voice like boards shattering on rocks, while the spirit of a trading ship might appear as a charming rogue with white, vacant eyes, as though they had never seen the sun.
Some spirits show themselves in other ways, the most common of these other forms being to actually animate the figurehead. In cases such as this, they often communicate with the entire crew. Other forms of displaying themselves include animated carvings, upon which they sprint as though the carved scenery was entirely real, appearing in the ghostlike form to the entire crew or, in some rare tales, the front of the ship coming apart and forming a giant, planked maw, from which a rumbling voice issued forth.
The abilities that are unique to a given spirit are varied indeed. Common ones involve influencing the winds or ocean currents, guiding the ship towards a destination (be it a specific island or simply good fishing grounds) and cursing another ship with poor conditions. Many spirits have more than one such ability.
There are more powerful abilities that can arise from overcoming harrowing scenarios. These abilities can border on the legendary, many of them believed to actually be some form of divine intervention. Such abilities include causing caches of supplies relevant to the spirit's interests to be found (i.e. on a gunship a cache of cannonballs and powder could be found where there was none before), the creation of such things as typhoons, storms and whirlpools and even the 'healing' of the ship from damage such as fire and hull breaches.
These abilities are rare indeed, and stories of their occurrence can always be found circulating in dockside taverns.

Hooks and Plotlines

1. In recent years, more and more anchor spirits have been coming into existence. More interestingly is the fact that they all have a habit of including references to an enigmatic being that goes by the moniker 'The Lord Under the Waves'. Oddly, when asked about this being, they respond with quizzical, blank looks, as though it had been some fleeting fragment of memory, such as a dream.

2. The cheap sailing that the PCs have chartered gets caught in a storm, and in escaping an anchor spirit is created. Unfortunately, the boat is actually a rum runner (or fantasy parallel) and takes any chance it can to taunt the law. Things go poorly when they pass near a Imperial Navy frigate, and the ship attempts to sideswipe the figurehead off.

3. The PCs, washed up on a deserted island, find a half intact ship. Seeing that there is enough there to cobble a small vessel together, they set to work only to find out that there is a half dead anchor spirit residing in the wreck. If they are able to salvage the figurehead and incorporate it into their piecemeal ship, they could not only have a better chance at getting home, but would have just gained a valuable ally if they can ever commission it to be included in a new ship.

4. A ghost ship is said to haunt the waters just out of sight of the local lighthouse whenever a fog rolls in. If the PCs investigate, it turns out that there is indeed an abandoned ship out there, although there is still a presence on board. This spirit, it seems, doesn't like company...

5. While sailing, the PCs hear a terrified scream from the edge of the ship. Investigating, they find that the wooden carvings have animated, and a small figure is being chased by stylized sea serpents. Similar events have been taking place on all vessels with Anchor Spirits, from their ethereal forms seeming to dry out and wither to figureheads bearing new scars, complete with painted blood. If the PCs can communicate with them, they discover that the spirits are in dire need of help. Should the PCs offer to help, they are drawn into the strange reality of the spirits of the sea, where the Anchor Spirits are the relative newcomers, and ancient beings don't take kindly to them. However, in this other world, Anchor Spirits and their kin have few abilities at all. In this reality, the PCs are the spirits, and it is they who wield strange new powers.