Isaacs—Faughn—Schick—Sargent: Deep-Sea Moorings 303 
cable and the scope are normally depended upon to minimize the vertical com- 
ponent of tension at the anchor. As the depth of water inereases and the practical 
limits of scope decrease, the weight of the anchor assumes greater importance. In 
taut mooring, where the pull is vertical or nearly so, the weight of the anchor 
usually predominates over other holding characteristics. 
TABLE 4 
CoMPARISON OF ANCHORS 
Comparative anchor weight for same holding power 
Approximate (in pounds 
Northill folding anchor number holding power ee 
(in pounds) 
Northill Kedge Stockless 
GP Resear Gnteceet aie aha) carat aa 240 6 35 60 
ee eres GOR cae a ERE EN 720 12 100 180 
QO AY tates chet eae esto tvertiacis 1200 20 170 300 
SO resets rece veer nehececteieine ie 1800 30 260 450 
SO par eet eraunirers eneyale repens Sees 2500 50 360 825 
G0) Siohnete Wario urerar tater nae ons 3600 80 500 900 
LOO ears ears tee erates ean eke 4500 100 570 1000 
Houpine Power or Nortuitt Utmiry ANCHOR 
Approximate 
Anchor weight holdingipower 
Anchor number (in pounds) 
(in pounds) 
GIR here ge ele tn ners Rute he 13 450 
DRA ey Sars risreder see eyaese shops) seopaisr aus 25 900 
QO R ener tear eacies etd claveeee eee ee 47 1575 
3) Ee raat ect peace Oh aN eo ean 70 2100 
HO een bak yao ontno esas been aalae 150 2625 
Various methods have been employed to increase the holding power and to 
minimize the vertical components of tension at the anchor. These have included 
the use of heavier components of cable adjacent to the anchor and of special 
weights or “clumps” ahead of the anchor. In some instances the weight of the 
clump may be several (three or more) times the weight of the anchor itself. 
In taut moorings, the situation is essentially reversed although the components 
used may be very similar; that is, the weight or clump itself becomes the anchor 
and a small drag anchor is provided to back it up. 
If it is necessary to place the anchor on a steeply inclined bottom, special pro- 
visions may be necessary to prevent it from dragging. Various sophisticated de- 
signs of anchors have been proposed for use in special situations. Most suggestions 
have been directed toward reducing the weight while increasing the holding 
power. Some have included various means of “burying” the anchor by driving, 
screwing, or otherwise forcing something into the bottom or by using a jet to make 
a hole, which then closes about the anchor. In order to reduce the lowering stresses 
on the mooring cable in deep water, some means of “floating” the anchor down 
