Does anybody have any info on "Peardrop" R.N. Submarine Decoys.

[Mush Martin]

/\ that should read R.N.

I am unable to locate info on "Peardrop"
an RN radar decoy device consisting of
an inflated aluminized balloon tethered to
a submerged anchor bouy, deployed by submarines
to create the illusion of a surfaceship/sub???
on the surface. Either its an invasion deception
method or a submarine evasion decoy.

according to ballentines illustrated allied secret weaps.
it was meant for one and used for the other,

any info would be appreciated.
M