Buoys are generally inspected and repainted every 6

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: anchors around it, forming a web. The container must have enough buoyancy to lift the cables far enough off the bottom for emplacers to readily secure it by grappling. Emplacers must locate the site exactly at the time of emplacement by visual sightings to fixed landmarks in the water or along the shore using several FRPs to establish a point where two sighted lines intersect. The recovery party locates the site by taking sightings on the reference points when they engage a mooring cable by dragging the bottom while diving. This method of mooring is the most difficult to recover. Emplacers can only use this method in bodies of water with smooth bottoms firm enough for dragging. Planners should also ensure the water at the site is not too deep, cold, or murky for diving. Structural Mooring D-94. Structural mooring uses a retrieval line run from the weighted container to a bridge pier or other solid structure in the water. The emplacer must fasten this line well below the low-water mark. 30 November 2010 TC 18-01 D-15 Appendix D Essential Data for Submersion D-95. Whatever method of mooring planners designate, they must carefully consider certain data before designing a submersible cache. If planners overlook any of the critical factors in the following paragraphs, they are likely to lose the cache. Buoyancy D-96. Many containers are buoyant even when filled. If the contents do not provide enough weight to submerge and secure the container in place, the emplacer must attach enough weight to the container to accomplish this. Table D-1 shows the approximate weight necessary to attain zero buoyancy. Table D-1. Zero buoyancy chart Zero Buoyancy Guide Container Dimensions (Inches) Empty Container Weight (Pounds) Approximate Weight to Attain Zero Buoyancy (Pounds) 7 x 9 x 8 1/2 5 15 7 x 9 x 16 1/2 8 31 7 x 9 x 40 16 77 7 x 9 x 45 17 1/2 88 7 x 9 x 50 19 97 D-97. The previous table utilizes several stainless steel container sizes. Soldiers can calculate the weight necessary to attain zero buoyancy for any container if they know the displacement of the cont...
View Full Document

This document was uploaded on 01/15/2014.

Ask a homework question - tutors are online