lowering line through the flaked downhaul cable is propelled into the 

 seafloor at velocities up to 400 feet per second. After penetration is 

 complete, a small pull on the main cable causes the fluke to key 

 (rotate into its resistive position) . After about a week the launch 

 vehicle, which is attached to the main cable by a corrosive link, is 

 designed to fall free thereby eliminating a potential source of abrasion 

 to the cable. 



ANCHOR DESIGN 



Flukes 



Two types of flukes were designed to satisfy performance goals in 

 seafloor sediments and rock. 



Sediment Flukes . To satisfy anchoring requirements in seafloor 

 sediments, two flukes were chosen, one fluke for sand and stiff clay 

 (sand fluke) and one for soft clay (clay fluke) . The basic shape of 

 these sediment flukes is illustrated in Figures 3 and 4 by the sand 

 fluke. It is shown with a piston, in its penetrating position, Figure 

 3, and its keyed or resistive position. Figure 4. The bent-plate 

 configuration was necessary to ensure that the fluke mass and drag area 

 were balanced about the piston. Fluke characteristics are: 



Clay Fluke 



63 

 30 



12.5 

 337 

 116 



24 



13 



These flukes were designed to conform to the requirements for an opti- 

 mum direct embedment anchor: they are streamlined for deep penetration, 

 they are quick keying, and they should obtain high holding capacities. 



The principal feature of the new fluke design is the technique 

 used for keying. This quick keying feature is patterned after the 

 free-fall anchor fluke (Smith, 1966). There is no mechanical connection 

 between piston and fluke at their contact point. The fluke is held 

 tight against the piston by the turnbuckles before launching as shown 

 in Figure 2, After firing fluke-piston contact is maintained during 

 initial penetration by the inertial force of the piston and in later 

 stages of penetration because soil drag on the fluke exceeds that on 

 the piston. After embedment, an upward pull on the cable attached to 



Characteristic 



Sand Fluke 



Length (in.) 



38 



Width (in.) 

 Plan Area (ft. ) 



18 



4.5 



Fluke Weight (lbs.) 



147 



Piston Weight (lbs.) 



116 



Piston Extension Weight 





(lbs.) 



24 



Connective Gear Weight 





(lbs.) 



13 



