Hacker News Reader

Comment by GJim | Hacker News Reader

And the mother of all unexploded WW2 ordance is the SS Richard Montgomery.

1.4kt of explosive sat in the Thames Eastury, 35 miles down river from central London, that nobody knows how to get rid of.

"it was determined that if the wreck of Richard Montgomery exploded, it would throw a 300 metres (980 feet)-wide column of water and debris nearly 3,000 metres (9,800 feet) into the air and generate a wave 5 metres (16 feet) high. Almost every window in Sheerness (population circa 20,000) would be broken and buildings would be damaged by the blast."

https://en.wikipedia.org/wiki/SS_Richard_Montgomery

View on HN

Hm, reminds me of the 2020 beirut explosion. It was 2.7 kt of ammonium nitrate.

Isn't that a kind of thing you just have to bite the bullet and deal with directly, because waiting only makes dealing with it more expensive with time?

Just evacuate the people and blow it up, accepting that it'll inconvenience a lot of folks and the national budget even more, but will also briefly revitalize the local economy, as every contractor there is will maximize the opportunity to suck out the funds set aside for repairing buildings damaged in the explosion - and make sure to record the disposal itself from every possible angle, with most expensive cameras government can buy, as selling clips of it to the media industry would be a licensing goldmine and recoup some of the costs.

Hell, turn it into a spectator event, and tourists coming to see it may just pay for the whole thing.

If they can spend 5 millions just for mast removal, I am pretty sure they could build some rough reinforced concrete dome / something similar all around it (15m depth ain't something impossible to build on) that could absorb most of the blast.

Say 50 million budget. Of course red tape, bureaucracy and just laziness/incompetence of state bureaucrats would make such budget balloon and drag for a decade or two, but it should be doable.

Water is a great blast-absorbent material.

If 15m of water can't contain the blast, adding concrete or similar is more likely to add solid projectiles to the explosion than diminish the force of the blast.

It's the opposite.

You probably wouldn't build a dome. Better to build a open top cylinder so that the explosion is directed up. Then gravity takes the heavy stuff right back down, while water comes out as rain. Though that would be very expensive and hide the explosion so you can't sell tickets.

Note that I'm not claiming the above is a good plan. Just that it is better than a dome.

Build a dome and put a spaceship on top. An improvised Project Orion.

Yes, but why be the politician or civil servant responsible for dealing with it when it will most assuredly be someone else's problem in a few years? The political upside of getting it done is low, and the risk and cost are high.

OTOH make a spectacle out of it, and forever secure your place in history books.

I think the 1960s salvage effort of the similar SS Kielce which detonated while they were trying to remove the explosives put off similar efforts for SS Richard Montgomery. Mind you, I'm not sure what they thought would happen since they attempted to clear debris from the wreck with explosives.

https://en.wikipedia.org/wiki/SS_Kielce

If you keep it from exploding long enough the explosives will degrade and stop being explosives. Seawater ain't great for stuff.

Some explosives degrade by becoming more and more sensitive and dangerous, not less.

Source?

TNT or Dynamite will 'sweat' crystals as it is aging.

https://www.munirem.com/recovery-and-neutralization-of-dynam...

As dynamite bundles age past their recommended shelf life, the absorbing material degrades, and the liquid nitroglycerin begins to seep or "sweat" out of the matrix.

https://en.wikipedia.org/wiki/Dynamite

One example: https://en.wikipedia.org/wiki/SS_Richard_Montgomery

> When the condition of the munitions was originally assessed there was concern that copper azide, an extremely sensitive explosive, would be produced through reaction between lead azide and copper from fuze components (lead azide would react with water vapour, rather than liquid water, to form hydrazoic acid, which could react with copper in the detonating cap to form copper azide).

> An investigation by New Scientist magazine in 2004, based partly on government documents released that year, concluded that the cargo was still deadly, and could be detonated by a collision, an attack, or even shifting of the cargo in the tide. The deterioration of the bombs was so severe that they could explode spontaneously.

Disappointing to see you being downvoted for asking for a source, though this is the sort of thing we are increasingly seeing on HN.

The question though is at what rate will things happen. Not everything degrades that way as well. The ideal state would be everything degrades such that when those that do become more sensitive explode there isn't enough else still explosive (because it degraded to nonexplosive) and so we don't get the secondary explosions that makes the whole dangerous.

We are also hoping that future technology will figure out a better way to handle this.

Sounds like each consecutive politician making a gamble that, if it actually does explode and kill people, it will be during someone else's term in the office.

Trying to remove it is also a gamble though: if anything goes wrong the bomb squad dies and it destroys everything anyway. There are no good answers, and it hasn't gone wrong yet.

According to Wikipedia the leading plans were more like evacuate everyone, build some protection around it, then dissemble it one piece at a time and blow the pieces up individually.

This makes sense if you can tolerate some chance of the whole thing blowing up, but you'd still prefer not to replace all those windows.

They just cut the masts off it last week, apparently to stop boats heading over to look at it.

I saw them while still attached earlier this summer - very spooky, like being next to a potentially active volcano.

BBC says it was to stop the masts collapsing and maybe setting the thing off https://www.bbc.co.uk/news/articles/c6wyz44x4g33o

So a cautious person would naturally wonder when will an adversary (such as Iran?) choose to do something with this situation.

Small point: People throw around the "kt" label when it means very different things in context. Nuclear weapons are generally measured in TNT equivalent, the hiroshima bomb being roughly 15,000 tonnes equivalent (15kt). This is so common that "kt" has blurred in the mind and we forget that different explosives can be considerably more or less powerful than their TNT equivalent.

The 2020 Beirut explosion involved 2,750 tonnes of ammonium nitrite which exploded with a force equivalent to 1,100 tonnes of TNT.

The SS Richard Montgomery sank with 1,400 tonnes of explosives, of a variety of types, some of which could be more powerful than TNT.

Reply on news.ycombinator.com