Three 12-inch-long tripod leg supports (see Table for specifications) were 

 welded to the tripod head (Fig. 4) . The legs were placed into the leg supports 

 and held in place by 0.5-inch (1.3 centimeters) steel pins through each tripod 

 leg and corresponding leg support. Two holes were drilled into the underside 

 of the tripod head for installation of steel eyebolts to support the come-alongs 

 during core extraction. 



A further modification entails cutting a core pipe slot, 5 inches (12.7 

 centimeters) wide and 5 inches deep (rounded at the inside end) , in the tripod 

 headplate (Fig. 4). A metal spring-loaded bar, the slot gate, is placed across 

 the core pipe slot. Attached to the end of the gate is a release cord to open 

 and close the gage from ground level. During extraction, the core is guided 

 through the slot and held vertical by the tripod. After the core breaks free 

 of the sediment, the come-alongs are removed. The release cord is then pulled, 

 opening the slot gate, and the core falls freely to the ground. This design 

 permits a safe extraction of long cores often unobtainable with other coring 

 systems. 



III, 



SECOITOARY COMPONENTS 



Three- inch aluminum irrigation pipe, a gas-main sealer plug, hacksaws, and 

 rope are all stock items and easily purchased. It is recommended that the 

 bottom end of the core tube be cut at a 45° angle and sharpened with a file 

 for easier penetration. 



Figure 4, A closeup of the tripod headplate. Leg supports welded to 

 the headplate are shown, along with the core pipe slot and 

 spring-loaded slot gate with attached cord. The underside 

 of the headplate has two steel eyebolts for fastening the 

 come-alongs . 



