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[KitS]

On Monday the 26th I crossed over from the IoW to Portsmouth on the Whitelink car ferry, and en route noticed this pair in the centre of the Solent heading west.


At first it looked like the freighter was towing the tug, but as the 2nd pic shows the tug is way off to starboard, and it's also going backwards! I've no idea what could be going on, anyone any ideas?













Sorry for the odd reflections, but the pics were taken through the ferry windows.

[Umi_Ryuzuki]

The tug is providing additional steerage or braking foce, if required, or just on the line in case of emergency.
It is also what is know as an "indirect tow". Where you see the tug at an angle to the line
of travel, the pilot and tug skipper are using the hull to create drag. This can double or triple the
amount of force the propellers can produce on their own. The offset to starboard will act as a 'rudder'
force, and pull the stern to that side as the ship travels. 

[Colin Bishop]

Tug is probably acting as a steadying line, if that is just outside Portsmouth it is a fairly narrow deep channel. The Portsmouth tugs often travel backwards in such situations. Dodes on here will be able to confirm.

Colin

[T888]

This looks like one of the Fawley Refinery Marine Terminal tugs which are power a pair of five bladed Voith Schneider, so can the tug can operate going an astern as well as ahead. It look as it’s being used as the braking tug and to help steerage.



Apex, Phenix and Tenax are custom designed Voith tractor tugs constructed by Astilleros Gondan SA of Figueras, Asturias, Spain using a design produced by Robert Allan Ltd in conjunction with Carl J Amundsen.
The ships are powered by two Rolls-Royce Bergen (Rolls-Royce Marine AS) C25:33L8P main engines that can produce a total of 6,850 bhp to power a pair of five bladed Voith Schneider cycloidal propulsion units (32 R5/250-2). The tugs are fitted with the Voith Turbo Fin, which is a rotating cylinder device incorporated in the leading edge of the deep skeg designed to increase the amount of lift when the vessel is operating in the escort towing mode.
The Voith Turbo Fin ensures stable flow and increases lift by virtue of the larger angle of attack to the water, resulting in a significantly higher transverse forces. The steering force of a Voith tractor tug with Voith Turbo Fin is up to 25% greater than that of a conventional tractor. The increased steering force enhances the safety of ships carrying hazardous loads, such as oil tankers, when they are escorted by Voith tractor tugs in difficult waters.

[KitS]

Hmm, that makes sense. They were east of Southampton Water and heading that way when I saw them.


Thanks for your expertise in maritime matters gentlemen. 

[Big Ada]

Hmm, that makes sense. They were east of Southampton Water and heading that way when I saw them.


Thanks for your expertise in maritime matters gentlemen. 

  and Umi !!

[derekwarner]

..Don't forget Danielle in Switzerland 

[Circlip]

Must have missed Danielle's posting on the subject?


  Regards  Ian.

[dodes]

After a large supertanker ran aground some years ago through some nav problem, Southampton Port Authority insists now all large tankers must have a escort tug attached to the rear as a safety precaution.