An airdrop type buoy apparatus, which is dropped by a flight vehicle, such
as aircraft, that is flying in the air, to a water surface of sea or lake
to be floated as a marker, a hydrographic conditions measuring device or
the like, for flexibly coping with a shock at the time of landing on the
water to absorb the landing shock on a balloon and also suppressing the
rise of an inner pressure of the balloon so that the balloon is hardly to
burst.
