Manta 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 |
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) |
- Drilled hole required to install.
- Installation may be difficult. Pilot hole may be required.
- Holding capacity limited by working load of anchors
- Holding capacity limited by soil failure.
- Not recommended in these soils.
- 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.