STU
STU
STU
STU
STU

STU Metric Range

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Hi-Force STU series sub-sea bolt tensioners are designed and manufactured to suit the demanding requirements of divers operating in harsh sub-sea environments. With an easy to operate two piece design comprising of a quick fit/ release threaded puller and a hydraulic load cell with integral bridge and an extra long 1.18 inch piston stroke to reduce re-setting operations. Hi-Force STU series sub-sea bolt tensioners offer a consistent, reliable and cost effective method of tensioning sub-sea bolted joints. All hydraulic load cells are suitable for different thread sizes and interchangeable quick fit/release pullers can be ordered separately, as required, resulting in even greater flexibility and cost savings.

  • Capacities from 28.8 to 279 tons
  • Bolt sizes M24 to M90 diameter
  • Working pressure 21750 psi
  • Single acting design with manual piston retraction
  • High grade alloy steel construction
  • Simple two piece design for easy operation by divers subsea
  • Visible maximum piston stroke indicator
  • Dual quick connect couplings for easy connection
  • Designed to fit most sizes of ANSI and API flanges and some Compact flanges
  • Interchangeable quick fit pullers to cover secondary bolt sizes for each STU model
  • Customized and special design tensioners are available on request
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Sub-Sea Bolt Tensioners Metric Range
Sub-Sea Bolt Tensioners Metric Range
Model Number Quick fit pullers Bolt Thread Size Capacity Effective area inch2 Stroke inch Weight lbs Tommy Bar
kN Tons
STU1-24 QFP1-24 M24 x 3 256 28.8 2.65 0.79 7.5 TTB06
STU1-27 QFP1-27 M27 x 3 256 28.8 2.65 0.79 7.5 TTB06
STU2-30 QFP2-30 M30 x 3.5 430 48.4 4.45 1.18 13.2 TTB08
STU2-33 QFP2-33 M33 x 3.5 430 48.4 4.45 1.18 13.2 TTB08
STU2-36 QFP2-36 M36 x 4 430 48.4 4.45 1.18 13.2 TTB10
STU3-39 QFP3-39 M39 x 4 553 62.2 5.72 1.18 16.5 TTB10
STU3-42 QFP3-42 M42 x 4.5 553 62.2 5.72 1.18 16.5 TTB10
STU4-45 QFP4-45 M45 x 4.5 756 85 7.82 1.18 21.6 TTB10
STU4-48 QFP4-48 M48 x 5 756 85 7.82 1.18 21.6 TTB12
STU5-52 QFP5-52 M52 x 5 1168 131.3 12.07 1.18 32.0 TTB12
STU5-56 QFP5-56 M56 x 5.5 1168 131.3 12.07 1.18 32.0 TTB14
STU6-60 QFP6-60 M60 x 5.5 1649 185.3 17.04 1.18 50.3 TTB14
STU6-64 QFP6-64 M64 x 6 1649 185.3 17.04 1.18 50.3 TTB16
STU6-68 QFP6-68 M68 x 6 1649 185.3 17.04 1.18 50.3 TTB16
STU6-72 QFP6-72 M72 x 6 1649 185.3 17.04 1.18 50.3 TTB16
STU7-76 QFP7-76 M76 x 6 2483 279 25.66 1.18 78.5 TTB16
STU7-80 QFP7-80 M80 x 6 2483 279 25.66 1.18 78.5 TTB16
STU7-85 QFP7-85 M85 x 6 2483 279 25.66 1.18 78.5 TTB16
STU7-90 QFP7-90 M90 x 6 2483 279 25.66 1.18 78.5 TTB16

Note: Tommy bars are not included. Hi-Force recommends one tommy bar for every four tensioners. Please note that the tommy bar listed will fit related quick fit puller; a different size may be required for the drilled hexagon nut.


Model Number Dimmensions in inch
A B C D E F
STU1-24 3.23 0.87 4.69 4.69 5.52 2.4
STU1-27 3.23 0.87 4.69 4.69 5.52 2.52
STU2-30 4.02 1.18 5.52 5.52 6.46 2.88
STU2-33 4.02 1.18 5.52 5.52 6.46 2.96
STU2-36 4.02 1.18 5.52 5.52 6.46 3.07
STU3-39 4.49 1.38 5.59 5.59 6.66 3.23
STU3-42 4.49 1.38 5.59 5.59 6.66 3.35
STU4-45 5.04 1.62 5.95 5.95 7.13 3.7
STU4-48 5.04 1.62 5.95 5.95 7.13 3.86
STU5-52 5.91 1.89 6.46 6.46 7.96 4.41
STU5-56 5.91 1.89 6.46 6.46 7.96 4.57
STU6-60 6.93 2.36 7.21 7.21 9.1 5.36
STU6-64 6.93 2.36 7.21 7.21 9.1 5.36
STU6-68 6.93 2.36 7.21 7.21 9.1 5.36
STU6-72 6.93 2.36 7.21 7.21 9.1 5.56
STU7-76 8.47 3.51 8.47 8.47 10.24 6.46
STU7-80 8.47 3.51 8.47 8.47 10.24 6.46
STU7-85 8.47 3.51 8.47 8.47 10.24 6.9
STU7-90 8.47 3.51 8.47 8.47 10.24 6.9