The first of a series of threads of single ship classes of the RN/RFA

Seabed Operations Vessel HMS Challenger (K07)

Challenger, ordered in 1979, was a multi role vessel capable of operating a diving bell to great depth, an ROV to even greater depth and the LR5 submarine rescue vehicle. She was built by Scott’s in Greenock with an expected in service date of 1982/3 at a cost of £80m

Named for the steam assisted corvette HMS Challenger of the expedition of 1872-76, widely regarded as the birth of modern oceanography, the new ship had big boots to fill! As an aside, the space shuttle Challenger was also named after her

https://en.m.wikipedia.org/wiki/Challenger_expedition

All was not well with the ship, or the shipyard. Redesigns, poor workmanship, industrial disputes etc meant that Challenger was not commissioned until 1984 and costs spiralled. Hansard states that it was now £154m. SSN Turbulent cost £160m and T42 York, £118m for comparison

She had a (then) revolutionary propulsion system: 5 16 cylinder Diesel engines coupled to 3.3kw electric motors driving 2 Voith Schneider propellers and 3 bow thrusters. She could hold her position in most sea states and alter it in 1m increments. Vital for deep diving ops

The stern A frame was for the Towed Unmanned Submersible: TUMS was a concept originally developed by the US but was never taken on by them because of many problems with the design. It was designed to deploy a depressor - a garage for the submersible about the size of a skip

The depressor would tow the submersible behind and below the ship to great depths and was piloted from the ops room. The problem was that it could be up to 2 miles behind the ship navigating over rocks and cliffs that the ship had already passed over...

...requiring software to allow for the delay. Second problem: it didn’t work. It was powered by 3kw of electricity which caused problems of its own and was never successfully deployed. It was vastly over budget and could not be used at the same time as the sat diving system

The diving system installed during build was woefully inadequate as it was built by a company that had had no previous diving experience. When tenders were invited the successful firm figured that if plans existed then they could build it and won the contract with the lowest bid

On requesting the plans, they were shown some concept of what the navy had in mind. It led to a system that was vastly over budget and never worked. Finally the ship was refitted by a company with a proven record at more cost. The ship now had a working diving capability to 300m

She had a moonpool to deploy an enormous diving bell and umbilicals required to sustain life at 300m. It is now apparently abandoned in Scotland and used by the oldest profession in the world

It’s easier to see the whole system in this short video

She could be role changed in 24 hours and deploy the LR5 submarine rescue submersible. However, the original design was to allow the submersible to lock onto the diving chamber complex to allow survivors to transfer under pressure if required– this system was never fitted

Although highly manoeuvrable, the top speed was 12 - 15 knots which meant if she was to be deployed to rescue a crashed submarine the time taken to reach the area was something that could become an issue. I actually did a SUBSMASH ex and this problem was very apparent

Although ostensibly a design disaster for the RN, Challenger completed many tasks that remain classified to this day. But government saw her as an extravagant white elephant and frankly, there was no argument against that. She was quietly withdrawn in 1990 and offered for sale

In 1993 she was purchased by Subsea Offshore and converted for decontaminating waste dumped in the Baltic, but was never used and remained on the Tyne until 2000. Then purchased by the Namibian Mineral company and towed to Gdańsk for conversion to a diamond recovery vessel

She was again sold to De Beers in 2003, further refitted and is now responsible for the collection of millions of pounds worth of diamonds.
As MV Ya Toivo, she’s in with a good shout of winning the ugliest ship afloat competition. Apart from the bridge, little is recognisable