An evolution of Seaeye's Type 3 & Type 4 TMS, this garage-style system uses a bale arm arrangement to spool tether on and off a fixed drum without the additional cost of incorporating a slip ring. Up to 250 metres of tether can be accommodated which is remotely controlled by the ROV pilot. The Type 8's improved mechanism and stainless steel frame make it virtually maintenance free.

The TMS Type 8 is adapted for use with all Seaeye vehicles except the Seaeye Falcon, Tiger and Jaguar, i.e.:

• Seaeye Lynx
• Seaeye Cougar-XT
• Seaeye Cougar-XTi
• Seaeye Panther-XT
• Seaeye Panther-XT Plus

A Seaeye TMS 8 comprises a side entry garage which can be adjusted to accommodate a number of vehicles (see above) with no skid, one skid or two skids. A detachable top section contains the tether management mechanism and controls. The tether is stored on a polypropylene bobbin with an active level-wind mechanism to spool the tether evenly onto and off the bobbin.

The bale arm is powered by a Seaeye thruster motor which is connected to the bale arm reduction gearbox by a flexible coupling. This thruster motor is chosen to be common with the ROV, to allow commonality of spares. The control electronics are contained in a one atmosphere, hard-anodised pressure housing and all connectors are Seaeye metal shell type.

The mechanism section is enclosed by equipment guards that can be hinged up or down without the use of tools to facilitate easy maintenance. All mechanism components are oil-compensated.

The subsea end of the armoured main lift umbilical cable is terminated with a load termination bullet, supplied with a load test certificate. Electrically the main lift umbilical is terminated at the TMS in an oil filled junction box. This hard anodised oil-filled and compensated junction box provides a central termination point for the armoured umbilical, the tether cable and the TMS electronics pod. This unit allows fast and simple electrical re-termination in the field, should this become necessary. At the surface, the umbilical is terminated into a slipring fitted to the winch.

A hydrostatic release mechanism ensures that the vehicle is held securely in the garage until it reaches a depth of 10 metres, safely below surface wave action. The spring-loaded latch mechanism allows the ROV to re-enter the TMS and be captured even in the event of TMS system failure.

At the working depth the ROV can be safely flown from the TMS to the extent of its tether. The pilot operates the TMS tether in and out mechanism from the hand controller (or the surface control unit or the foot switches) as he manoeuvres the vehicle. The length of tether spooled out is displayed on the comprehensive video overlay provided as standard fit on all Saab Seaeye ROVs. This is automatically calculated by the number of turns made by the bale arm mechanism during spooling in and out.