Explorer's harrowing experience of being trapped at Titanic stern in 2000

As a massive search continues for a missing tourist submersible with five people on board near the Titanic wreck, US journalist Michael Guillen recounts his harrowing experience of being trapped in a similar vessel during a dive in the North Atlantic back in 2000.

"I was the first correspondent ever to report from the wreck of the Titanic. So, naturally, I was excited," Dr Guillen, who was at the time science editor at America's ABC network, told BBC Radio 4.

He recollects that - together with diving partner Brian and Russian pilot Viktor - they went down in a small Russian submersible lowered from the Akademik Mstislav Keldysh research ship.

After touring Titanic's bow where "everything had gone well", the crew decided to head to the stern area some distance away.

The Titanic sank on 15 April 1912, after striking an iceberg. Before going down, the British passenger liner split into two parts.

"As we approached the stern area - flying over what's called the debris field - we were caught up... in a very fast-moving underwater current. So we ended up getting stuck in the propeller," says Dr Guillen, describing it as "huge".

"All of a sudden, there was just crash. We just felt this collision, and all of sudden debris... just huge chunks, rusted chunks of Titanic started falling on top of us."

Dr Guillen, a physicist and now a best-selling author, remembers that "it was pretty clear to us almost immediately we were stuck".

He says the pilot was a former Russian Mig fighter pilot, and he was trying to jostle the sub out.

"It's like you get your truck, your car stuck in the mud: you try to forward, backward, forward, backward. Just to try dislodge yourself.

"We all fell silent. We didn't want to disturb or distract Viktor. And we knew we were in a crisis. So we just kept quiet."

The sub eventually managed to get out "through the skill of Viktor", admits Dr Guillen.

"We were just fortunate. There was a better part of an hour we were stuck. And I already pretty much had said my goodbyes in my mind.

"I'll never forget this thought that came to my head: this is how it's going to end for you.

"But in the end, we sensed that something changed... there was a sense that we were floating."

The journalist recollects that all this was happening in complete darkness, as the pilot turned off the spotlight.

"We didn't want to say anything. I was like 'My gosh, is it possible that we are out of this?'

"Then I turned to Viktor, and I said: 'OK?' That was all.

"He only spoke broken English. And I'll never forget [how] he said this in a very low growling Russian accent: 'No problem.'"

"I breathed a sigh of relief."

Dr Guillen said it took them about two-and-a-half hours to get back to the surface, and people aboard the launching ship had been aware of a "crisis" situation.

He says that back in 2000, there were only two countries that had subs able to withstand enormous water pressure - France and Russia.

Comparing the 7.8m-long (26ft) Russian Mir sub he was in to the missing vessel Titan, he says: "Our sub was nothing like this luxurious sub. I've seen pictures of the interior of Titan - it's like a mansion."

Inside the tight vessel, there were "two benches on either side - that was me and my diving buddy, and in the middle - the pilot".

"I have a fear of water. It was already difficult for me to do this," admits Dr Guillen - but says he simply could not turn down the opportunity to report from Titanic's wreck.

Before the dive, the crew had been instructed on what to expect in the sub.

"We were briefed on a true story that had happened when another gentleman had been caught in the sub in a crisis," says the American journalist.

"And his first instinct was to go the hatch. Because your first instinct when you're trapped down there is, you stand up, you reach for the hatch, which is right overhead... thinking you're going to escape that way.

"This gentleman did that in a panic, and of course doomed himself because as soon as he does that, all it takes is one crack; the water comes in - it's under such enormous pressure: it's just a like razor blade - it cuts you in half.

"I was very concerned about someone doing this in the sub. So I immediately became vigilant," he recalls, adding that he was not panicking - but was "ready to gang-tackle anybody else in the sub who might panic".

"That helped distract me from the crisis we were in - it kind of gave me a purpose, a reason to not think about anything else," he says,

"And then - being a scientist - I immediately started taking an inventory in my mind: OK, how much our oxygen gonna last, what could we possibly do.

"I thought to myself how we could get out of this, and I reached a point that I really had to concede the really stark fact that there was no way out," he says, describing the conditions as "very hostile".

"That's when that voice came to my head - this is how it's going to end for you. And just experienced almost like a supernatural peace."

When asked about the missing Titan submersible, Dr Guillen is unable to contain his emotions.

"My heart is breaking for this five poor souls down there," he says in tears. "I know exactly what they are experiencing. There are just no words for it.

"I know what they are going through. I'm just praying so hard."