Tether Specifications

Tether Diameter

Units \ Type	Negative	Neutral	Performance
mm	8.51 +/- 0.38	11.18 +/- 0.50	8.18 +/- 0.50
inches	0.335 +/- 0.015	0.440 +/- 0.020	0.322 +/- 0.020

New tether was introduced in 2018. These tethers include a braided Kevlar around the conductors, are slightly different diameter and can be identified by an "FB" code printed on the tether.

Units \ Type	FB Neutral	FB Performance
mm	12.2 +/- 0.25	9.1 +/- 0.25
inches	0.440 +/- 0.010	0.358 +/- 0.010

Minimum Tether Bend Radius

Units \ Type	Negative	Neutral	Performance
mm	88.9	114	82.5
inches	3.5	4.5	3.25

Tether Connector Pin Configuration

Tether pin numbering in the connector is shown above. When looking at the mating surface of the connector, Pin 1 is the offset pin / socket. For male connectors, pins 2-8 proceed in a clockwise direction. For female connectors, sockets 2-8 proceed in a counter-clockwise direction.

Tether Pin Function and Conductor Wire Gauge

Pin	Function	Negative	Neutral	Performance
1	Video -	24	24	28
2	Video +	24	24	28
3	48 VDC +	16 (x2)	20 (x2)	24 (x2)
4	Aux + (APIC)	24	28	28
5	Ground	16 (x2)	20 (x2)	24 (x2)
6	Aux - (APIC)	24	28	28
7	RS-485 +/B	24	28	28
8	RS-485 -/A	24	28	28

All conductors are straight through, such that pin 1 in the male connector is connected to socket 1 in the female connector, and so on for all eight pins / sockets.

Conductor pairs 1 & 2, 4 & 6 and 7 & 8 are twisted.

Pins 3 and 5 use 2 conductors each for maximizing power transmission and tether flexibility.

Tether Buoyancy

Performance and Neutral tether includes buoyancy compensating foam that provides near neutral buoyancy in fresh water. Negative tether contains no foam and will sink. The connectors do not contain any buoyancy compensation and will sink slightly.

Tether Strength

All tether types include Kevlar that is rated at 450 kg (1,000 pounds), the connectors are rated 80 kg (175 pounds).

These values are breaking strength. The tether should not be subjected to a working strength greater than one half of the breaking strength. The ROV and tether are equipped with a strain relief cable and connectors, which are rated at 136 kilograms (300 pounds). The strain relief cable should be used to avoid separation of the tether connectors and loss of the ROV.

The maximum usable tether length is limited by the ability of the tether to transmit power and data signals. The maximum usable tether length of the Pro 4 Ultra is about 305 meters (1,000 feet). See the Tether Management section of the Operations Guide for more information.

Kevlar is a registered trademark of E. I. du Pont de Nemours and Company