Deployable ballast

A deployable ballast is a quest item

Gameplay
It attaches to the crashed B-29, one ballast on the underside of each wing, between the two engines (the location is indicated by a transparent ghostly outline). Once detonated, the plane is able to float on the ballasts.

Location
The deployable ballast is a quest item given to the Courier by Loyal at Nellis Air Force Base.

Related quests

 * Volare!

Behind the scenes
A deployable ballast is a reusable recovery system, attached to rockets or other small airborne instruments. The ballast is jettisoned after landing in water, allowing the item to become buoyant and to be recovered by a surface vessel.

Bugs
If the player attaches the ballasts on the plane and then goes back to Loyal and talks about the plane, Loyal will give the player two additional ballasts, which can't be removed from one's inventory even after the quest (because they'll still be marked as quest items). This can only be fixed with console commands.