This preview shows page 1. Sign up to view the full content.
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.
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.
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
(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.
- Winter '14