INTRODUCTION 



Subject and Purpose of Report 



This report describes the development by the Naval Civil Engineer- 

 ing Laboratory (NCEL) of a propellant-actuated direct embedment anchor 

 (deep water anchor), and reports the results of a land testing project 

 used to define the anchor's gun system performance. The project is 

 sponsored by the Naval Facilities Engineering Command. The overall 

 objective is to develop practical embedment anchors which are both 

 reliable and efficient for use in mooring deep ocean surface or sub- 

 surface structures. The anchor is designed to be functional in water 

 depths to 20,000 feet, to have a long-term holding capacity of 20,000 

 pounds, and to develop this capacity in seafloors from soft clay to 

 hard rock. 



Background 



Present deep water mooring installation techniques require contin- 

 uous at-sea operation through a long-time period; therefore, the instal- 

 lation process is subject to inclement weather. It would be advanta- 

 geous if improved hardware and procedures were available to ease and 

 speed installation. The solution to this problem, however, encompasses 

 a broad spectrum of considerations. Anchor designs, special appurte- 

 nances, connective gear, and special operational techniques are among 

 the more critical areas that need improvement. The single most impor- 

 tant consideration is the anchor design because improved anchors can 

 alleviate problems in the other areas. 



Based upon the operational requirements established in the program 

 objectives, the state-of-the-art, and the available time frame, it 

 appeared that this critical mooring problem could be most easily solved 

 through development of a propellant-actuated direct embedment anchor. 



The direct embedment anchor best satisfies the requirements of a 

 deep ocean anchorage. Two advantages of this type anchor are the 

 capability to embed directly into the bottom without the necessity of 

 dragging and the capability to resist significant uplift loads. Direct 

 embedment shortens the lowering and placement time, enhances the preci- 

 sion of placement, and reduces the quantities and sizes of accessory 

 gear. Uplift resistance provides for both reduced amounts and variety 

 of connective gear and greater flexibility of application of the anchor. 

 Of the direct embedment anchor types, e. g. , vibratory, propellant- 

 actuated, hydrostatic, free-fall, the propellant-actuated anchor offered 



