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Installing earth anchorsManta Ray and Stingray earth anchors are driven tipping plate soil anchors dependent on soil strength for reaction of tensile loads. Manta Ray anchors have working loads up to 20 kips, and Stingray anchors have working loads up to 50 kips. After driving the anchor to the required depth, the driving tool (called drive steel) is removed. The anchor is then tipped and proof tested with Williams Anchor Locking Kit from its edgewise-driving position to present its bearing area to the soil. This is called "load locking" and provides an immediate proof test of each anchor.

Manta Ray and Stingray anchors offer many significant advantages:

  • Fast, easy installation
  • Immediate proof test results  
  • No grout
  • Inexpensive installation equipment
  • Environmentally friendly
  • No drilling required
  • Superior Holding Capacity
  • Anchors for a wide range of soils & application

The simple, effective and low cost Manta Ray and Stingray anchor system represents a major breakthrough in "anchoring technology" with a multitude of uses in the utility, civil engineering and construction markets for:

  • Utility Poles
  • Retaining Walls
  • Sheet Piles
  • Seawalls
  • Pipelines
  • Erosion Control
  • Underwater Applications
  • Blockwalls
  • Scaffolding

There are eight Manta Ray Anchors and three Stingray Anchors with light to heavy duty holding capacities. Shown to the left are six different Manta Ray anchor heads. All anchors are made of galvanized ductile iron, can be driven with the drive steel set (except the MR-88 & M-68) and can be tested to the desired holding capacity with the load locker. The anchors are designed to utilize solid steel rods as load carrying members.

Manta Ray & Stingray Anchor Structural Properties

Anchor Structural
Safety
Factor 2:1
Diameter** Part
Number
Weight
Per
Each
MR-68 2.5 kips
(11 kN)
3/8" - 16 UNC
(10 mm)
B8S-03 1 lbs.
(0.45 kg)
MR-88 5 kips
(22 kN)
1/2" - 13 UNC
(12 mm)
B8S-04 2.2 lbs.
(1 kg)
MR-4  8.5 kips
(36 kN)
3/4"
(20 mm)
R61-06 4.7 lbs.
(2.1 kg)
MR-3 10 kips
(45 kN)
3/4"
(20 mm)
R61-06 6 lbs.
(2.7 kg)
MR-2
20 kips
(89 kN)
3/4"
(20 mm)
R61-06 10 lbs.
(4.5 kg)
MR-1 
20 kips
(89 kN)
3/4"
(20 mm)
R61-06 12 lbs.
(5.4 kg)
MR-SR
20 kips
(89 kN)
3/4"
(20 mm)
R61-06 21 lbs.
(9.5 kg)
MK-B 20 kips
(89 kN)
3/4"
(20 mm)
R61-06 85 lbs.
(38.5)
Sting Ray Safety Factor Part Number Working Load Weight
SR-1 45.5 kips
(198 kN)
1-1/8"
(28 mm)
R61-09 47 lbs.
(21.3 kg)
SR-2 50 kips
(223 kN)
1-1/8"
(28 mm)
R61-09 66 lbs.
(30 kg)
SR-3 50 kips
(223 kN)
1-1/8"
(28 mm)
R61-09 91 lbs.
(41.2)
Our Anchor Rods are fully threaded and can be field cut and coupled.
**Anchor Rod Lengths:  R61-06 & R61-09 up to 50 feet uncoated. B8S-03 & B8S-04 up to 20 feet
Recommend: Galvanized rods should be cut to size prior to galvanizing to insure good nut fit.

Manta Ray Anchor Holding Capacities in Listed Soils

Common Soil
Type Description
 Typical
Blow
Count
"N" Per
ASTM-D1586
MR-68
MR-88
MR-4
MR-3
MR-2
MR-1
MR-SR
MK-B
Peat, Organic Silts;
Inundates Silts, Fly Ash
0 - 5
N.A.
0.2-0.9 kips
(.9-4 kN)
(4,6)
0.3-1.5 kips
(1.3-7 kN)
(4,6)
0.8-3 kips
(3.5-13 kN)
(4,6)
2-5 kips
(9-22 kN)
(4,6)
3-8 kips
(13-37 kN)
(4,6)
4-12 kips
(18-53 kN)
(4,6)
6-16 kips
(27-71 kN)
(4,6)
Loose fine Sand;
Alluvium; Soft-Firm Clays;
Varied Clays; Fills
4 - 8
0.4-.8
(1.8-3.5 kN)
(4,6)
0.9-1.5 kips
(4-7 kN)
(4,6)
1.5-2.5 kips
(7-11 kN)
(4,6)
3-5 kips
(13-22 kN)
(4,6)
5-8 kips
(22-36 kN)
(4,6)
8-12 kips
(36-53 kN)
(4,6)
9-14 kips
(40-62 kN)
(4,6)
13-20 kips
(58-89 kN)
(4,6)
Loose to Medium Dense
Fine to Coarse Sand; Firm
to Stiff Clays and Silts
7 - 14
0.75-1.25 kips
(3.5 -6 kN)
(4)
1.5-2.5 kips
(7-11 kN)
(4)
2.5-4 kips
(11-18 kN)
(4)
5-8 kips
(22-36 kN)
(4)
7-10 kips
(31-44 kN)
(4)
10-15 kips
(44-67 kN)
(4)
14-18 kips
(62-80 kN)
(4)
20 kips
(89 kN)
(4)
Medium Dense Coarse
Sand and Sandy Gravel;
Stiff to very Stiff Silts and Clays
14 - 25
1-1.5 kips
(5-7 kN)
(4)
2-3 kips
(9-13 kN)
(4)
3.5-4.5 kips
(16-20 kN)
(4)
7-9 kips
(31-40 kN)
(4)
9-12 kips
(40-53 kN)
(4)
15-20 kips
(67-89 kN)
(4)
18-20 kips
(80-89 kN)
(4)
20 kips
(89 kN)
(2,4)
Medium Dense Sandy
Gravel; Very Stiff to
Hard Silts and Clays
24 - 40
1.5-2 kips
(7-9 kN)
(4)
3-4 kips
(13-18 kN)
(4)
4.5-6 kips
(20-25 kN)
(4)
9-10 kips
(40-45 kN)
(4)
12-18 kips
(53-80 kN)
(4)
18-20 kips
(80-89 kN)
(2,4)
20 kips
(89 kN)
(2,4)
20 kips
(89 kN)
(2,4)
Dense Clays, Sands
and Gravel;
Hard Slits and Clays
35 - 50
2-2.5 kips
(9-11 kN)
(4)
4-5 kips
(18-22 kN)
(4)
6-8.5 kips
(27-36 kN)
(4)
10 kips
(45 kN)
(2,4)
15-20 kips
(67-89 kN)
(2,4)
20 kips
(89 kN)
(2,4)
20 kips
(89 kN)
(2,3,4)
20 kips
(89 kN)
(1,3)
Dense Fine Sand;
Very hard Silts and Clays
45 - 60
2.5 kips
(11 kN)
(2,3,4)
5 kips
(22 kN)
(2,3,4)
8.5 kips
(36 kN)
(2,3,4)
10 kips
(45 kN)
(2,3,4)
20 kips
(89 kN)
(2,4)
20 kips
(89 kN)
(1,3,4)
20 kips
(89 kN)
(1,3)
20 kips
(89 kN)
(1,3,5)
Very Dense and/or
Cemented Sands;
Coarse Gravel and Cobbles
60 - 100+
2.5 kips
(1 kN)
(1,3)
5 kips
(22 kN)
(1,3)
8.5 kips
(36 kN)
(1,3)
10 kips
(45 kN)
(1,3)
20 kips
(89 kN)
(1,3,4)
20 kips
(89 kN)
(1,3)
20 kips
(89 kN)
(1,3,5)
20 kips
(89 kN)
(1,3,5)

1 - Drilled hole required to install.
2 - Installation may be difficult. Pilot hole may be required.
3 - Holding capacity limited by working load of anchors
4 - Holding capacity limited by soil failure.
5 - Not recommended in these soils.
6 - Wide variation in soil properties reduces prediction accuracy.
Pre-constructed field test recommended.
Minimum 2:1 Safety Factor Recommended
* Use this chart for estimation only.
* True capacity must be tested with anchor locker.

Stingray Anchor Holding Capacities in Listed Soils

Common Soil
Type Description

 Typical Blow
Count "N" Per
ASTM-D1586
SR-1 SR-2 SR-3
Peat, Organic Silts;
Inundates Silts, Fly Ash
0 - 5 N.A. N.A. N.A.
Loose fine Sand;
Alluvium; Soft-Firm Clays;
Varied Clays; Fills
4 - 8 13-19 kips
(58-82 kN)
(4,6)
19-28 kips
(85-125 kN)
(4,6)
24-37 kips
(107-165 kN)
(4,6)
Loose to Medium Dense
Fine to Coarse Sand; Firm
to Stiff Clays and Silts
7 - 14 16-24 kips
(72-107 kN)
(4)
27-36 kips
(120-160 kN)
(4)
37-48 kips
(165-214 kN)
(4)
Medium Dense Coarse
Sand and Sandy Gravel;
Stiff to very Stiff Silts and Clays
14 - 25 24-32 kips
(107-142 kN)
(4)
31-48 kips
(138-214 kN)
(4)
48-50 kips
(214-253 kN)
(4)
Medium Dense Sandy
Gravel; Very Stiff to
Hard Silts and Clays
24 - 40 29-41 kips
(129-182 kN)
(4)
46-50 kips
(205-223 kN)
(4)
50 kips
(253 kN)
(4)
Dense Clays, Sands
and Gravel;
Hard Slits and Clays
35 - 50 39-45.5 kips
(173-198 kN)
(4)
50 kips
(253 kN)
(2,4)
50 kips
(253 kN)
(2,3,4)
Dense Fine Sand;
Very hard Silts and Clays
45 - 60 45.5 kips
(198 kN)
(2,4)
50 kips
(253 kN)
(2,4)
50 kips
(253 kN)
(2,3)
Very Dense and/or
Cemented Sands;
Coarse Gravel and Cobbles
60 - 100+ 45.5 kips
(198 kN
(1,3)
50 kips
(253 kN)
(1,3)
50 kips
(253 kN)
(1,3,5)
  1. Drilled hole required to install.
  2. Installation may be difficult. Pilot hole may be required.
  3. Holding capacity limited by working load of anchors
  4. Holding capacity limited by soil failure.
  5. Not recommended in these soils.
  6. Wide variation in soil properties reduces prediction accuracy. Pre-constructed field test recommended. Minimum 2:1 Safety Factor Recommended * Use this chart for estimation only. * True capacity must be tested with anchor locker.
Interline

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