Ships of this tonnage have two independent hydraulic pump units for the steering gear
Certainly on the Australian coast, a 100,000 tonner would use one pump from Kembla to Headland & on the return voyage the other pump unit was used......
The circuitry was such that if one pump failed, the other would cut in...if both pumps fail, hydraulic accumulator storage was sufficient to return the rudder to mid ships & PO check valving then locked the rudder .....then chain blocks were available to stroke the rudder after the PO checks were disabled
This is all surveyable equipment ...many years ago.......tasks of mine were to oversee the stripdown of such pumps for both Lloyds & DNV survey
In the late 70's...the Australian Nation Line vessel Mt Newman [104,000 tonner] ...had one 55 GPM Sunstrand radial piston steering gear pump failed Lloyds survey....the ship could not leave port as without the second pump being operational, the vessel fell out of the Society's classification

......just by chance, the Iron Cumberland was astern of the Newman & the Cumberland had the identical 55 GPM Sunstrand pumps in her cranes....+ one spare........so we borrowed the spare pump from the Cumberland...& the Newman sailed on schedule
ANL paid for the replacement pump for the Cumberland to be imported from Europe......
I find it difficult to understand this exchange between the Colombo & a Maesrk being caused by a steering gear failure......Derek