gear leg were deployed in succession. Then the anchor assembly was 

 lowered with 1-inch wire rope leading from the port drum of the winch 

 and fairled over the port side of the ship. 



The operation showed that though the anchor can be placed in deep 

 water, special rigging arrangement is required with existing ship 

 equipment. The size and weight of the launch vehicle imposed severe 

 conditions on the handling equipment. A lighter l aunch ve hicle wit h 

 less drag through the water during retrie val would h e an asset. 



DISCUSSION 



The present design as modified through testing partially fills the 

 void in anchoring capability for salvage operations that currently 

 exists as a result of inherent limitations of conventional anchors. 

 The anchor can be directly embedded without a preset pull operation in 

 hard seafloors such as coral and it will develop holding capacities 

 that exceed the strength of a standard beach gear leg. Also, by 

 employing a different type of anchor-projectile it can be set in sand 

 and mud seafloors though the holding capacity and reliability of 

 functioning in these seafloors is less than in coral. However, 

 significant further development is required before the broad operational 

 and performance goals set at the beginning of the program can be attained. 



Explosive anchors and conventional anchors each possess inherent 

 characteristics that currently appear to give each type exclusive 

 advantages over the other in individual situations. Prominent 

 advantages of the explosive type of anchor are its ability to penetrate 

 directly into the seafloor, to resist uplift loads and loads from all 

 directions, and to function in hard seafloors such as coral. Prominent 

 advantages of the conventional type of anchor are its simple construction 

 and the fact that the force applied to it tends to embed it further 

 rather than to extract it (in the case of explosive anchors, the 

 force is opposite in direction to the embedding force). Also, the 

 capability to use chain with conventional anchors greatly reduces 

 abrasion and wear of connective gear, thus increasing service life. 

 Another fact pertinent to all anchors is that their efficiency as 

 measured by holding-capacity-to-weight-ratio goes down as size increases. 

 This factor is especially important in the design of explosive anchors 

 because of the energy required to accelerate a large mass. 



Limited amounts of hardware of the present design are stored at 

 NCEL and available for emergency use. Drawings and specifications for 

 the procurement of additional items and an interim operations manual 

 have been prepared (NAVSHIPS Technical Manual, 1970). However, further 

 minor refinements of the design are advisable to improve its handling, 

 functioning and reliability. An attachment package to support and/or 

 protect the touchdown firing mechanism, the explosive (MDF) leads and 

 the downhaul cables and a retainer to keep premature force off of the 

 shear pins used to secure the anchor-projectile against the gun barrel 

 prior to firing are needed. The cable release mechanism should be 

 improved by eliminating the need for the release bar pull cable, 

 Figure 7. 



12 



