Spectacle Island

Spectacle Island is a location and settlement in the Commonwealth in 2287.

Background
Spectacle Island is a small island on the coast south-east of Boston, near to Warwick homestead. The original settlers on the island had constructed a basic settlement with a sonar pulse beacon that released a high pitched sonic pulse capable of repulsing or killing mirelurks. The beacon is represented by a structure similar to a siren or radio antennas connected by a long wire to a sunken ship, as the ship's generator room is still operational and provides power for the beacon.

The appearance of raiders on the island suggests the settlers fled or were killed. The raiders disabled the pulse beacon, looted the area and left, allowing the mirelurks to return.

A beached barge on the northeastern portion of the island has a large shipment of Vault-Tec crates within it. It is unknown if these were being shipped to work on one of the incomplete vaults of the Commonwealth such as Vault 88, Vault 114 or Vault 118, or if these supplies were to be used in the construction of a new vault.

Settlement
To unlock the island for use as a settlement, the Sole Survivor must go to the sunken boat to the south and flip the switch on the circuit breaker. This will cause the screen to shake and a mirelurk queen and several hunters will emerge, as well as potentially a legendary mirelurk deep king.

To finish the unlocking process, one must go back and flip the circuit breaker on the radio tower. After a few seconds, this will send out a pulse which will drive all remaining mirelurks to the shores of the island. It is not necessary to kill the queen, as she is affected by this pulse as well. The workshop will then unlock, and one will be able to build at any point on the island.

Layout
The island has several buildings scattered across it (mostly shacks and ruined houses). The north side of the island contains several crafting stations in a small shed across from a destroyed house. The main workshop, along with a radio tower, is located in the center of the island. To the south is a destroyed boat containing the Luck bobblehead as well as a large power generator that connects to the radio tower through a series of pylons. Mirelurks populate the shores, as well as the wreckage of several boats.

Notable loot

 * Fat Man in the half sunken green tugboat on the southern tip of the island.
 * Luck bobblehead on the same half sunken tugboat to the south, sitting in a locker.
 * Mini nuke on the first floor of the destroyed house, sticking out of some debris on the floor.
 * Signal checklist in a small shack in the middle southeast of the island. This describes the instructions regarding the island's most unique feature: a sonic pulse beacon that repulses mirelurks.
 * Two Nuka-Cola Quantums in a broken fridge in an underwater, wrecked house (with a skeleton in a wheelchair facing a modern TV and radio) just off the southwest coast. From the derelict hut where Randy is found, head west towards Warwick homestead and dive down 33-50 feet out to sea. Unfortunately, these are often glitched under soil within the fridge. The water physics can make them roll out onto the wooden floor when approaching however, so check it occasionally and the player character may be able to reach one or both.

Appearances
Spectacle Island appears only in Fallout 4.

Behind the scenes

 * The island is likely based on the real Spectacle Island in Boston Harbor. For most of the 20th century, it was a garbage dump used by the inhabitants of Boston. During the construction of the civil engineering mega project known as The Big Dig, the island's garbage dump was capped off with dirt from tunnel construction and the island transformed into a park. It is now a part of the Boston Harbor Islands National Recreation Area and features a marina, life-guarded swimming beach, visitor center, snack bar, walking trails, etc. Spectacle Island is staffed by park rangers and staff year-round by the Massachusetts Department of Conservation and Recreation.
 * Incidentally "The Big Dig" is also the name of a quest which incorporates elements similar to the real project.
 * It is possible that the crashed/beached barge is a reference to sci-fi author Neal Stephenson's "eco-thriller" "Zodiac" - a barge crashes on Spectacle Island during the narrative of that book.

Bugs

 * Even after turning the power generator on the circuit breaker still signifies that the power switch is off even though the tower pylons are lighting up and showing powered on. Occurs when all mirelurks are not killed that correspond with the event of turning on the generator.
 * If one activates the generator before finding the metal shack the game sometimes won't let the player character flip the second breaker. On PC, to solve that issue open command, target the workbench and type CallFunction SetOwnedByPlayer 1. Then flip the switch one or two times to be in the upper position (again). Now you should be able to open the build menu, but maybe cannot store things to the workbench. To solve that, fast travel to another location and back and it should work fine.
 * If one places a structure that affects settlement stats (such as a turret, bed or a water purifier) on one side of the island and moves to the other side, the stats given may go away, even if it is fully operational. This can affect the happiness of the settlement in a negative way and can be fixed if you move back to the side with the structure, but this is a very temporary fix, as the bug may repeat itself.
 * This is due to the game engine being set to load only 5 world grids (which it is by default) and it therefore unloads resources after traveling to the other side of the island.
 * This can be fixed by setting "uExterior Cell Buffer=100" (default is 36) and "uGridsToLoad=9" (default is 5) in the Fallout 4 INI/configs or using Fallout 4 Tweaker. This will increase load distance of resources which will enable the player to enjoy the entire island.  This will however reduce FPS slightly on standard or lower end machines.