Data Sheet

ManualsBrandsBlueRobotics ManualsUUV / ROV PartsBlueRobotics Fathom ROV Tether (25m)

6/8/2018 Fathom Tether

http://docs.bluerobotics.com/fathom/ 1/12

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Fathom Tether

Introduction

The Fathom Tether is a high quality tether cable designed specically for ROVs and other subsea applications. It is

neutrally buoyant, has 350+ lb breaking strength, and is embedded with water-blocking bers to seal any leaks. The

tether has a diameter of 7.6mm and is slimmer than the vast majority of comparable ROV tethers.

We put a lot of time into making sure that it has impeccable electrical qualities. The tether carries 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. Each pair is individually jacketed inside the cable to maintain reliable properties and

minimize interference between each pair of wires.

Quick Start

1. Prepare the ends of your tether for use as shown in the installation tutorial.

2. Be sure to tin the ends of the conductors prior to installing the tether into your vehicle.

3. Firmly attach the tether to your vehicle by following the 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.

Specications

Specication Table

Physical  

Item Value 

Tether Diameter 7.6 mm 0.30 in

Summary of content (12 pages)

PAGE 1
6/8/2018 Fathom Tether Fathom Tether  Introduction The Fathom Tether is a high quality tether cable designed speci cally for ROVs and other subsea applications. It is neutrally buoyant, has 350+ lb breaking strength, and is embedded with water-blocking bers to seal any leaks. The tether has a diameter of 7.6mm and is slimmer than the vast majority of comparable ROV tethers. We put a lot of time into making sure that it has impeccable electrical qualities.
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6/8/2018 Fathom Tether Physical Weight 0.043 kg/m 0.0287 lbs/ft Buoyancy in Freshwater Neutral Buoyancy in Saltwater Slightly Positive Wire Gauge 26 AWG Working Strength 35 kgf 80 lbf Breaking Strength 155 kgf 350 lbf Minimum Working Bend Diameter 200 mm 8 in Electrical Item Value DC Resistance @ 20°C 0.0386 Ω / ft Characteristic Impedance @ 1 MHz 120 Ω Capacitance @ 1 kHz 16.5 pF / kft 54.
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6/8/2018 Fathom Tether A datasheet for the polyethylene jacket material is available here: DF4960 Polyethylene Foam (/fathom/DF4960.pdf). Installation Stripping the Jacket 1. Wearing a protective glove, bend the cable at the point that you want to cut. Bending the cable makes it easy to see when you have cut through the jacket. 2. Using a sharp knife, gently slice the jacket open using a sawing motion. Stop when the jacket opens and you can see the white Dacron bers underneath the jacket. 3.
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6/8/2018 Fathom Tether 5. Pull o the length of jacket that you just cut. http://docs.bluerobotics.
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6/8/2018 Fathom Tether 6. Unwind the clear plastic wrap and white bers that are wound around the outside of the conductor bundle to the jacket. 7. Separate out the white Dacron bers from the conductor bundle and cut o the all white bers and plastic wrap at the jacket. http://docs.bluerobotics.
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/8/2018 Fathom Tether Stripping the Twisted Pairs 1. Take a jacketed, twisted pair and grab it near the end. 2. Use a knife to split the pair. Cut into the pair 5 to 10 mm and then you can pull the wires apart using your ngers or pliers. http://docs.bluerobotics.
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6/8/2018 Fathom Tether 3. Cut the excess clear jacket. 4. With the 26 AWG slot on a set of wire strippers, remove the insulation from each conductor. http://docs.bluerobotics.
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6/8/2018 Fathom Tether 5. Tin the ends of the conductors. Installing into a Penetrator 1. Clean the jacket and the tether penetrator that will touch epoxy with isopropyl alcohol. 2. Twist the Kevlar and the conductors so that they will slide through the penetrator. http://docs.bluerobotics.
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6/8/2018 Fathom Tether 3. Insert the tether into the penetrator. 4. Mix a small batch of Loctite Marine Epoxy (https://www.bluerobotics.com/store/tools/loctite-marine-epoxy/) and pour into a potting syringe. (https://www.bluerobotics.com/store/tools/tool-potting-kit-r1/) 5. Fill the penetrator hole with the epoxy. Move the tether from side to side within the hole to ensure the epoxy is lling all gaps.
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6/8/2018 Fathom Tether 6. When the epoxy has dried, apply epoxy to the other side of the penetrator using the same method. 7. Cut o excess Kevlar strands, and that’s it! http://docs.bluerobotics.
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6/8/2018 Fathom Tether Strain Relief 1. Grab the tether somewhere between about 16 and 24 inches away from the penetrator and loop it around a plastic thimble. (https://www.bluerobotics.com/store/parts/fathom-p-thimble-r1/) 2. Firmly attach three alternating heavy gauge zip ties (included with thimble) at the base of the thimble. 3. Firmly attach the thimble to your vehicle using at least two heavy gauge zip ties. http://docs.bluerobotics.
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6/8/2018 http://docs.bluerobotics.