On Monday 22nd September 1958 Glen Usk was withdrawn from service earlier in the season than had been planned and was replaced by Cardiff Queen.
The previous day, Sunday 21st September, was intended to be the last day of the season for Cardiff Queen with the remaining couple of weeks of mostly Cardiff/Weston ferry connections, with a final couple of down Channel sailings, left to Glen Usk.
However the previous few weeks had seen issues with Glen Usk. On the late evening of Wednesday 27th August she had run aground on the mud while approaching the Cardiff pontoon and it was not until gone 3am the following morning that she floated off on the rising tide and was able to discharge her 200 or so passengers on their way home after an evening out in Weston.
During the afternoon of Wednesday 10th September whilst approaching Weston her steering gear failed and so she hit the pier with some force causing considerable damage to her starboard sponson and the pier itself.
On Sunday 21st September, while Cardiff Queen was off on a day trip from Cardiff, Penarth and Barry to Ilfracombe and Lundy, Glen Usk was rostered for the Cardiff/Weston ferry with departure from Cardiff (9.15am), Penarth (9.25am), Weston (10.45am), Cardiff (11.45am), Penarth (11.55am), Weston (1.10pm), Cardiff (2.10pm), Weston (3.20pm), Cardiff (4.25pm), Penarth (4.35pm), Weston (5.35pm) for Barry (6.30pm). She was then scheduled for one more circuit for an “Evening Musical Trip” but unfortunately that never happened.
During the afternoon trouble developed with the boiler water feed pump and that was the end of that. For any who don’t know, once the steam has done its work in the engine it is sucked out from the low pressure cylinder by a vacuum made by the air pump and passes into the condenser in which it is cooled down into water again. This condensate is then pumped back into the boiler by the feed pump so, in theory at least, as much, or almost as much, condensate is pumped back into the boiler as is used as steam by the engine so that the level of water in the boiler remains, or almost remains, constant.
If the feed pump doesn’t work then that condensate isn’t pumped back into the boiler so the level of water in the boiler goes down and therefore needs topping up. On lake steamers the boiler can be topped up from fresh lake water but at sea, whilst you could put seawater into a boiler in a dire emergency, it is not something that you would want to do as you wouldn’t want to get salt, which is potentially corrosive, in a boiler
On most steamships the boiler feed pump is driven by the main engine so that the rate of return of condensate is set by the speed of the engine which itself is governed by how much steam is being used so everything remains in balance. Some ships have independent feed pumps and all have other pump options which can be linked in to get you home in an emergency if the main boiler feed pump packs up. But that is a get you home sort of thing rather than a method to keep the ship in service.
So Glen Usk was withdrawn and Cardiff Queen took over her roster the next day, Monday 22nd September, and continued with it until the last trips of all of the season on Monday 6th October 1958 between Cardiff, Penarth and Weston