Self-supporting Marker Buoy

Abstract

A self-supporting marker buoy includes an upper unit, a lower unit, and a rim-engaging cover. The upper unit is a frustum which further includes a base opening facing downwards, a hollow center, and a base rim around the base opening. The lower unit is an upside-down frustum, which further includes a top opening facing upwards, a hollow center, a top rim around the top opening, and a water entry at the bottom of the lower unit. The radius of the base opening of the upper unit is less than that of the top opening of the lower unit.

1 . A marker buoy, which includes
 an upper unit, which further
 a base opening with a radius B facing downwards, 
 an upper hollow center, and 
 a base rim around said base opening; 
   a lower unit, which further includes
 a top opening with a radius T facing upwards, 
 a lower hollow center, 
 a top rim around said top opening, and 
 a water entry at the bottom of said lower unit; and 
   a rim-border-engaging cover.   
     
     
         2 . The marker buoy as claimed in  claim 1 , wherein said upper unit is of the shape of a frustum with a height of U, and said lower unit is of the shape of an upside-down frustum with a height L, wherein L is less than L, and said radius B of said base opening is less than said radius T of said top opening. 
     
     
         3 . The marker buoy as claimed in  claim 1 , wherein said rim-border-engaging cover is made of tender and resilient materials. 
     
     
         4 . The marker buoy as claimed in  claim 1 , wherein said rim-border-engaging cover is an elastic clip-on. 
     
     
         5 . The marker buoy as claimed in  claim 1 , wherein an air-flowing hole is disposed at a pre-determined height of said lower unit.