I have no info on the available wire lengths on the Battler for this tow, but her is the specs for the Maersk B-Class vessels: maersksupplyservice.com/Documents/B-Type.pdf
As can be seen, the vessel was more than amply supplied with winch capacity
Towing/Anchor handling equipment
Winch Make Brattvaag
Drums 3 with spooling device
AH drum Max. pull 500 ts and 625 ts static brake
Capacity 5,850 m x 84 mm wire
Towing drums 2 x max. pull 400 ts and 575 ts static brake
Capacity of each drum 2,610 m x 84 mm wire
Secondary winches 2 x 170 ts (Mærsk Battler)
2 x 140 ts (Mærsk Boulder)
2 x 120 ts (Mærsk Blazer)
Chain lockers 2 x 201 m3 and 2 x 179 m3
Guide pins 2 x 300 ts Triplex
Shark jaws 2 x 700 ts Triplex
Stern roller 2 x 3.25 m x 4.00 m.
I found a report for a towing approval inspection I did on the Maersk Shipper in Nov/2014 for towage of a Semi-sub MODU from Singapore to Labuan for lay-up.
At that time the tow wires were as follows:
Main Tow Wire* Second Tow Wire** Spare Tow Wire**
2,300 M 1,100 M. 1,300 M
83 MM. 83 MM. 83 MM.
EIPS EIPS EIPS
6X41(WS)IWRC 6X41(WS)IWRC 6X41(WS)IWRC
BS 447 m.t. 450 m.t. MBL 500 m.t.
CR 529 SOCKET, BOTH ENDS
*) ALSO USED AS WORK WIRE.
**) Spooled ready on Tow drums
This is fairly typical for Maersk AHTS of similar BP. (>200 tonnes)
But I cannot say if the Battler had the same, or similar wires on board, nor which drum(s) were used.
PS> From the pictures I have seen, there appears to be relatively small Yokohama fenders placed between the hulls and not much distance between the bridge wings. (Damaged bridge wing wouldn't sink the vessels though)