STU Metric Range

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 30 mm 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 256 to 2482 kN
  • Bolt sizes M24 to M90 diameter
  • Working pressure 1500 bar
  • 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

Sub-Sea Bolt Tensioners Metric Range
Model Number Quick fit puller Bolt Thread Size Capacity Effective area cm2 Stroke mm Weight kg Tommy Bar
kN tonnes
STU1-24 QFP1-24 M24 x 3 256 26.1 17.1 20 3.4 TTB06
STU1-27 QFP1-27 M27 x 3 256 26.1 17.1 20 3.4 TTB06
STU2-30 QFP2-30 M30 x 3.5 430 43.9 28.7 30 6.0 TTB08
STU2-33 QFP2-33 M33 x 3.5 430 43.9 28.7 30 6.0 TTB08
STU2-36 QFP2-36 M36 x 4 430 43.9 28.7 30 6.0 TTB10
STU3-39 QFP3-39 M39 x 4 553 50.4 36.89 30 7.5 TTB10
STU3-42 QFP3-42 M42 x 4.5 553 50.4 36.89 30 7.5 TTB10
STU4-45 QFP4-45 M45 x 4.5 756 77.1 50.4 30 9.8 TTB10
STU4-48 QFP4-48 M48 x 5 7560 77.1 50.4 30 9.8 TTB12
STU5-52 QFP5-52 M52 x 5 1168 119.1 77.9 30 14.5 TTB12
STU5-56 QFP5-56 M56 x 5.5 1168 119.1 77.9 30 14.5 TTB14
STU6-60 QFP6-60 M60 x 5.5 1649 168.1 109.9 30 22.8 TTB14
STU6-64 QFP6-64 M64 x 6 1649 168.1 109.9 30 22.8 TTB16
STU6-68 QFP6-68 M68 x 6 1649 168.1 109.9 30 22.8 TTB16
STU6-72 QFP6-72 M72 x 6 1649 168.1 109.9 30 22.8 TTB16
STU7-76 QFP7-76 M76 x 6 2483 253.2 165.6 30 35.6 TTB16
STU7-80 QFP7-80 M80 x 6 2483 253.2 165.6 30 35.6 TTB16
STU7-85 QFP7-85 M85 x 6 2483 253.2 165.6 30 35.6 TTB16
STU7-90 QFP7-90 M90 x 6 2483 253.2 165.6 30 35.6 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 mm
A B C D E F
STU1-24 82 22 119 119 140 61
STU1-27 82 22 119 119 140 64
STU2-30 102 30 140 140 164 73
STU2-33 102 30 140 140 164 75
STU2-36 102 30 140 140 164 78
STU3-39 114 35 142 142 169 82
STU3-42 114 35 142 142 169 85
STU4-45 128 41 151 151 181 94
STU4-48 128 41 151 151 181 98
STU5-52 150 48 164 164 202 112
STU5-56 150 48 164 164 202 116
STU6-60 176 60 183 183 231 136
STU6-64 176 60 183 183 231 136
STU6-68 176 60 183 183 231 136
STU6-72 176 60 183 183 231 141
STU7-76 215 89 215 215 260 164
STU7-80 215 89 215 215 260 164
STU7-85 215 89 215 215 260 175
STU7-90 215 89 215 215 260 175