The gun-reactor consists of a gun barrel and a disc- or cone- 

 shaped part that serves to help counteract the reaction force, generated 

 as the anchor-projectile is accelerated away from the gun-reactor. A 

 removable breech block at the breech end of the gun-reactor provides 

 the means for inserting and containing the propellant charge. The 

 gun- reactor can be reused to fire a succession of anchor-projectiles. 

 Its reuse is contingent upon two factors. First, it must be retrieved. 

 Retrieval is not a difficult problem in shallow water but is a major 

 consideration in deep water. Second, it must be reconditioned after 

 a specified number of discharges due to the severe shocks it experiences 

 at each recoil. 



Another important feature of explosive anchors is the wire rope 

 pendant which must be attached to and trail the anchor-projectile into 

 the seafloor. The pendant must be packaged or otherwise arranged in 

 a manner that will permit it to payout at high velocity without 

 entanglements, kinks, or other damaging effects. The pendants for 

 the three designs are accommodated in two ways. For the two commercial 

 anchors, which are small by comparison to the MERDC anchor, the pendants 

 are packaged in a figure 8 so that they payout without a twist and 

 without damage. Figures 10 and 11. For the larger MERDC anchor, the 

 pendant is faked on a board fastened to the anchor assembly. Figure 12. 



Two methods are employed to discharge the explosive anchors; one 

 is by contact with the seafloor and the other is by signal control from 

 the surface. For the contact method, a rod extends below the main anchor 

 assembly and contacts the seafloor as the assembly is lowered. Upon 

 contact, it mechanically actuates an electrical or mechanical firing 

 system. Electrical or mechanical actuations may be used on any of the 

 designs. For the signal control method, the anchor with an attached 

 tripod support framework is lowered to the seafloor. Then with the 

 anchor supported and oriented on the seafloor by the tripod, it is 

 discharged using an electrical cable extending to the surface. During 

 work by NCEL with the MERDC anchor, a refinement of the contact method 

 was developed whereby discharge of the anchor occurred a preset time 

 after touchdown. This method improved operations procedures and safety. 



Tests and Results . A summary of deep water tests and results with 

 the explosive anchor designs is presented in Table 1. The tests 

 demonstrated that explosive anchors can function in deep water. The 

 tests also served to identify major problem areas associated with the 

 use of explosive anchors in deep water. Chief problems concern: 



1. Preparing and regulating the firing process; 



2. Orienting the anchor properly with respect to the seafloor 

 prior to discharge; 



3. Monitoring and establishing control over the penetration 

 process ; and 



4. Retrieving the expensive, reusable gun-reactor portion. 



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