The Fathom Tether is a high quality tether cable designed specifically for ROVs and other subsea applications. It is neutrally buoyant, has 300-350 lb breaking strength, and is embedded with water-blocking fibers to seal any leaks. With diameters of 4mm and 7.6mm, these tethers are slimmer than the vast majority of comparable ROV tethers.
The tether carries one or four unshielded twisted pairs (UTP) of 26AWG wire. These pairs are colored and arranged in the same fashion as a Cat5 networking cable including cross-talk resistance. A pre-installed Binder 770 plug makes it easy to connect to the FXTI and Fathom Spool. A cable penetrator is installed at the other end to interface with the BlueROV2 or any of our watertight enclosures.
The slim tether really shines when it comes to its size. Its slim profile makes it ultra low-drag, making it ideal for deep dives, high current dives, and long distance dives where the drag from the tether is really noticeable. The size also makes it incredibly portable and easy to handle. A hundred meter tether weighs just 3 lb (1.4 kg) and can be managed by hand very easily.
Since the slim tether only has two wires, it can only be used for the primary communication of the BlueROV2. There are no spare twisted pairs when using this cable, which means that it is not compatible with applications where you need extra tether pairs.
The core of the cable contains Kevlar strands for strength and Dacron fibers for space filling. Both fibers are impregnated with waterblocking compound to block any leaks caused by nicks or rips in the cable. The high-visibility yellow polyurethane foam jacket resists abrasion and provides neutral buoyancy.
The stiffness of the cable is designed to be flexible enough to give plenty of freedom to your ROV, but stiff enough that it does not become tangled easily.
The capabilities of this tether are meant to provide design flexibility and a wide variety of uses. Pololu carries the 3 position 0.1” (2.54mm) Crimp Connector Housings and male crimp pins that may be used for connecting your own devices to the spare tether terminations.
We also have this cable available by the meter with no terminations at either end.
Contents
- 1 x Fathom ROV Tether with Installed Binder 770 Plug and WetLink Penetrator (of the selected length)
- 1 x Header Pin to Ferrule Adapter to Connect to Fathom-X
- 1 x Tether Cable Thimble
- 1 x M10 Nut
- 1 x O-ring for Bulkhead
- 5 x Heavy Duty Zip Ties
Specifications
| Parameter | Standard Fathom Tether (4 twisted pair) | Fathom Slim Tether (1 twisted pair) |
|---|---|---|
| Performance | ||
| Maximum Rated Depth (seawater) | 1000 m | |
| Design Lifetime¹ | 3 years or 500 cycles to rated depth | |
| Temperature Rating (air) | -25 to 60°C | |
| Temperature Rating (water) | 0 to 40°C | |
| Installed Penetrators and Connectors | ||
| Topside | Binder 770 Plug (6-8mm) | Binder 770 Plug (2.5-4mm) |
| ROV Side | M10-7.5mm-HC | M10-4.5mm-HC |
| Twisted Pairs | 0.1" Header Pins, 3 Position | |
| Tools | ||
| Compatible Bulkhead Wrench | BR-100977-010 | |
| Recommended Installation Torque | 3.5 Nm | |
| Physical | ||
| Tether Diameter | 7.6 mm | 4.0 mm |
| Weight | 0.043 kg/m | 0.012 kg/m |
| Outer Jacket | Polyurethane Foam | |
| Buoyancy in Freshwater | Neutral | |
| Buoyancy in Saltwater | Slightly Positive | |
| Wire Gauge | 0.14 mm² / 26 AWG | |
| Working Strength | 35 kgf | |
| Breaking Strength | 155 kgf | |
| Minimum Working Bend Diameter | 75 mm | 25 mm |
| Recommended WLP Thru Hole Diameter | 10.2 mm | |
| Bulkhead Thread | M10 x 1.5 | |
| Bulkhead Thread Length | 20 mm | |
| Bulkhead/Nut Wrench Flats | 16 mm | |
| Overall Assembled Height From Endcap | 25 mm | 23.5 mm |
| Overall Outer Diameter | 18 mm | |
| Bulkhead O-ring Size | AS568-013 Buna-N 70A | |
| Bulkhead/ Plug Material | 7075-T6 Anodized Aluminum | |
| Wetted Materials | Buna-N Rubber Molykote 111 Compound 7075-T6 Anodized Aluminum PUR Foam FKM |
|
| Electrical | ||
| DC Resistance @ 20°C | 0.127 Ω/m | 0.146 Ω / m |
| Insulation Resistance @ 500 VDC | > 1640 MΩ/km | - |
| Voltage Rating | 300 VDC | |
| ¹ Design life was used to inform testing in an accelerated environment, does not reflect warranty period. | ||
Pinout
Standard Fathom ROV Tether
| Pair | Wire | Color | Binder Connector Pin # |
|---|---|---|---|
| Pair 1 | Wire 1 | Blue | 1 |
| Wire 2 | Blue/White | 2 | |
| Pair 2 | Wire 1 | Orange | 3 |
| Wire 2 | Orange/White | 4 | |
| Pair 3 | Wire 1 | Green | 5 |
| Wire 2 | Green/White | 6 | |
| Pair 4 | Wire 1 | Brown | 7 |
| Wire 2 | Brown/White | 8 |
Fathom Slim ROV Tether
| Pair | Wire | Color | Binder Connector Pin # |
|---|---|---|---|
| Pair 1 | Wire 1 | Blue | 1 |
| Wire 2 | Blue/White | 2 |
Cross Section
Standard Fathom ROV Tether
Fathom Slim ROV Tether
Revision History
29 June 2023
- FATHOM-TETHER-NB-4P-26AWG-25-R3-RP SKU changed to BR-100862-025
- FATHOM-TETHER-NB-4P-26AWG-50-R3-RP SKU changed to BR-100862-050
- FATHOM-TETHER-NB-4P-26AWG-100-R3-RP SKU changed to BR-100862-100
- FATHOM-TETHER-NB-4P-26AWG-150-R3-RP SKU changed to BR-100862-150
- FATHOM-TETHER-NB-4P-26AWG-200-R3-RP SKU changed to BR-100862-200
- FATHOM-TETHER-NB-4P-26AWG-300-R3-RP SKU changed to BR-100862-300
- FATHOM-SLIM-NB-1P-26AWG-50-R2-RP SKU changed to BR-100985-050
- FATHOM-SLIM-NB-1P-26AWG-100-R2-RP SKU changed to BR-100985-100
- FATHOM-SLIM-NB-1P-26AWG-200-R2-RP SKU changed to BR-100985-200
1 July 2022
- FATHOM-SLIM-NB-1P-26AWG-XX-R2-RP – Initial Release
- Updated preinstalled penetrator to WetLink Penetrator
14 March 2022
- FATHOM-TETHER-NB-4P-26AWG-XX-R3 – Initial Release
- Updated preinstalled penetrator to WetLink Penetrator
7 August 2018
- FATHOM-TETHER-NB-4P-26AWG-XX-R2 – Update to new construction with polyurethane foam jacket
3 November 2017
- FATHOM-SLIM-NB-1P-26AWG-XX-R1 – Initial Release
Quick Start
1. Install the cable penetrator on a watertight enclosure end-cap, such as the back of the BlueROV2.
2. Firmly attach the tether to your vehicle by following the thimble strain relief tutorial or some other method that prevents the tether from pulling directly on the tether penetrator. The tether can twist the penetrator loose if you do not provide strain relief.
Guides
Thimble use with Fathom Tether and Fathom Slim Tether
Tether Repair Guide
