Deckstone

"As blue to red Anchor us home With stone on lead The waves churn foam" -The Western Wind

Mechanics & Inner Workings

The mutual attraction of split pan'Punde stones cause the blue stone's lead vessel to tilt the mounting as well as compressing or stretching the perpendicular springs. These angles and stresses can be translated into a distance and direction of the red stone's vessel allowing for the ship's position to be known. The red stone's vessel stone cauldron only doesn't require gradation because the red stone always angles in the direction of the sunrise.
The precision of these measurements depends on the size of the pan'Punde stone and the distance the hemisphers are apart. For small stones the typical error is 1 mile for every 500 miles apart. Larger stones can have the same precision at distances of up to 5000 miles.
Militaries and large merchant groups use a dangerous piggyback technique in which one or more ships in a fleet put their anchor stone in cargo relying on their sister ships for navigation. The anchor stone can then be installed at their destination to create a new home harbor with appropriate calibration of the blue deckstone. Lord Troxon of Crawshank famously lost half his armada during a hurricane using this technique giving birth to the euphemism Trox.
More complicated arrangements of multiple deckstones, Relational Navigation have been used by naval forces in warfare, piracy, exploration and rescue operations.

Manufacturing process

A pair of lead vessels, one containing the sapphire half and the other the ruby half of a pan'Punde stone, are created by an Alchemist and then mounted in stone cauldrons. Navigators then carefully score the mounts and cauldron with demarcations calibrated to the stones contained in the leaded canisters. The deckstone containing the red stone (often called the Anchor) is then placed at a precisely noted geographic location such a merchant company's main port. The blue deckstone (often given a name by the ship's crew) is installed on a ship.

Weight

800-3000 pounds

Dimensions

12" to 24" diameter x 2' to 4' length.

Base Price

1000 gp to 50000 gp

Raw materials & Components

Sealed lead canister containing a red or blue hemisphere from a pan'Punde Stone mounted in a graduated stone cauldron