How much?

[jester]

Originally Posted by kato13

This took 75 lbs or RDX and 350 shaped charges. Kinda beyond the scope of the mission but it is a pretty picture.

But, I see three different secontions falling in the photo. So, what if you just wanted to drop 1 section? That is all I propose, drop a wide enough section to make it beyond use.


Unless there is damn upriver where a esxplosives genious and a mountainclimber turned explorer can blow which will release a torrent of water that will take out the brigde. If that's the case then the problem is solved.

[Grimace]

Make sure you all wave to the nice FBI agents reading this page!

As far as taking down the bridge, your best bet would be to damage one of the main supports enough with all the explosives you can that it weakens the bridge. Then, like smokewolf suggested, you let the enemy run their convoy on to the bridge and let it collapse from the weight upon the weakened section. Thus topples the section of bridge while inflicting losses upon the enemy convoy.

You can plan all you want, but trying to run a covert op against a bridge like that, without having access to all of the nifty gadgets, gizmos and extractions equipment necessary for proper insertion and extraction will result in a big hairy mess that leave any major plans largely undone.

Make it quick, make it simple, and throw all your explosives at one major point in hopes of successfully weakening the main support structure of the bridge enough that weight and/or nature will bring it down. If you're real lucky, or have more explosives than I think you could probably, reasonably have in Twilight, then you might just be able to drop a section of the bridge right away. It won't be pretty, it won't be quiet, but if you just want something "blowed up", you throw enough explosives at it and it'll drop.

Oh, and it would also help out in a major way if you've got either a civil engineer or a very, very good combat engineer who can pinpoint the exact points, the minimal exact points, that would be best to plant the explosives to cause the greatest weakening effect on the bridge.

[Legbreaker]

While I agree that the supporting structure are the preferred elements to attack, I rather doubt anything much less than a truckload of explosives is going to do the job without may hours of preparation (boring holes, etc).
I would also be rather hesitant to plan for just damaging the bridge and hoping the weight of subsequent vehicles bring it down. Chances are that unless very lucky or the calculations and application of charges is spot on, not enough will be inflicted or the damage will be so great even a blind man would be able to spot how unsafe the structure is.
The aim really should be to drop as much of the bridge into the river as possible whilst leaving as little as possible for the following enemy engineers to work with. Ideally as has been previously mentioned, even starting repairs should need significant effort to simply clear the debris.
With only the explosives a small team of SF troops are able to carry (remembering they're probably already loaded down with 40+ kgs of weapons, ammo and other vital equipment) the best that could be hoped for is cratering of the decking, and damaging supporting beams. With luck/planning, some beams mad be dropped across the decking creating more work for the engineers (both clearing and ensuring the structure is still able to carry tanks, etc).
The more debris that can be created, even without significant damage to the structural components the better - more locations to place booby traps and anti-handling charges.
While obviously not ideal, slowing the enemy by causing them to spend time on the bridge may be enough.

Unfortunately one has to remember that modern armies possess a much greater ability to cross water obstacles than even just a few decades ago. Many armoured vehicles are either capable of swimming, or in the case of some heavier AFVs able to use snorkels. A dropped, or even badly damaged bridge may not hold up the enemy advance for long....

[Targan]

I still think my barge full of ANFO idea has merit.

[Legbreaker]

So do I. Unfortunately it's not the stealthiest of insertion methods and you still need to pack the charges on the structure...
Unless you're looking at several tonnes of it in VERY close proximity (any air gaps significantly degrade performance to the point where you might only shake the rust loose).

[jester]

YOU ARE WRONG!

Google the following guys,

"Col John Ripley" and "Bridges at Don Ha."

1 man, crawled carrying full combat harness and weapons and satchel charges under a reinforced bridge that could handle TANKs. And he was able to place several charges, enough to drop the spans destroying the bridge. So, it is possible, if one man is able to do it, than I think a team can manage it.

And then the idea of modern mech vehicles with their amphib capabilities.

Sure, the armored vehicles can cross, but who here has traversed water in a armored vehicle? <Marines forward!> its painfully slow, and thus you are an easy target for everything to include slingshots. But, that is not the only thing.

A mech vehicle requires a large support and supply chain. Once the mech amphib vehicles cross, how long can they operate? They'll need fuel, ammo, mechanics to service them, the crews will need food and rest, so how long can a mech force operate if they cross a river and are forced to operate without a supply train? That has been the thing that has doomed most massive military disasters in history! A poor or non existant supply line, it destroyed Napoleon in Russia, the Germans in Russia, the British in the US Revolution, the Americans in the Philipine Campaign and several others. They could not sustain themselves and soon withered and became combat ineffective. Granted, these are major campaigns and a small column of BMPs is a small action, but if they are cut off and do not have the chance for fuel or ammo resuply they will soon be a sitting target unable to withdraw and soon unable to defend themselves.

[Targan]

Originally Posted by Legbreaker

So do I. Unfortunately it's not the stealthiest of insertion methods and you still need to pack the charges on the structure...
Unless you're looking at several tonnes of it in VERY close proximity (any air gaps significantly degrade performance to the point where you might only shake the rust loose).

How about packing the front third of a barge with explosives, backing and topping that section with steel plate and other tamping and filling the rear third with ballast. Then either use the current to hold the barge against the pillar at water level or water proofing the explosives and scuttling the barge next to the footings?

[Legbreaker]

Hmm, could work....
I like the idea of sinking it and using the water to transmit the expplosive force into the pilings. Still a big, difficult job though...

As for the one man dropping the bridge, how well built was they? Was it a modern, highly engineered structure such as we're discussing here?
Or little more than logs or hastily contructed temporary spans (eg a bailey bridge)?

Just because somethings capable of supporting a WWII tank (not a lot of weight really compared to modern days AFVs) doesn't mean it's anything like a modern autobahn bridge intended to support maybe a hundred times that weight.

Yes, Col Ripley may have been exceedingly brave and pulled off a very difficult task, but I don't feel it's really comparable.

[Fusilier]

Originally Posted by jester

YOU ARE WRONG!

I would say that is still subjective to whatever bridge you are talking about. Not fact, and definitely not wrong to think its not probable considering the objective given.

Originally Posted by jester

So, it is possible, if one man is able to do it, than I think a team can manage it.

Again, it still depends on the bridge and a huge amount of other already mentioned factors. Its not a given that it'll be possible to drop it into the river just because of the amazing feat of said event. The bridge in Vietnam was only about a third the size. And was likely built using different bridge architecture styles (US seabees) that what you see in Europe along the major highways over one the largest rivers.

Another reason I think the Ripley example isn't comparable is that he didn't need stealthy deep behind the lines insertion. He had a bunch of marines providing cover fire since they were defending the bridge area, not sneaking in deep behind enemy lines. The saboteurs in this example will be probably dealing with an already dug in force on both sides and won't have the firepower to sufficiently cover a demo group. Therefore IMO its significantly much more difficult task.

Originally Posted by jester

amphib crossing is painfully slow, and thus you are an easy target for everything to include slingshots.

If its behind enemy lines, any amphib water crossing is probably not going to be coming under fire including that from slingshots. Since its the only bridge standing, for the Danube armies, it'll be already well defended. That further increases the problems for every extra man you attempt to get to the objective and work on it without being discovered.

For logistics, it only stands to reason with me, that an engineer unit would be deployed nearby with bridging/pontoon equipment if for only the reason you mentioned. The Serbs for example did this during the bombing campaigns a couple years ago. Bridge goes down, but a few hours later lighter traffic can cross. Bridges in North Vietnam is another example.

[Rainbow Six]

Before I viewed this thread I thought it was a follow up to the "Entertainment Pricing" thread...

[Cdnwolf]

I just had an idea... since the river substains a lot of barge and boat traffic including small river cruise ships... maybe grab a working ship... and ram the support pillars?

[pmulcahy11b]

Originally Posted by Cdnwolf

I just had an idea... since the river substains a lot of barge and boat traffic including small river cruise ships... maybe grab a working ship... and ram the support pillars?

That is innovative. Maybe the ship itself can carry explosives that detonate on contact...or, if properly protected from the impact, the ship can carry an assault force instead of explosives.

[smokewolf]

Originally Posted by Cdnwolf

I just had an idea... since the river substains a lot of barge and boat traffic including small river cruise ships... maybe grab a working ship... and ram the support pillars?

Most support pillars are reinforced concrete and steel. Don't think it would do much on it own.

From http://www.ens-newswire.com/ens/nov2...-11-08-093.asp
"The collision damaged the 900-foot container carrier Cosco Busan, allowing 58,000 gallons of bunker fuel to spill into the bay. CALTRANS has confirmed there is no structural damage to the bridge."

If a 900' container ship loaded with 58k of fuel can't damage the supports I don't think a little barge is.


And one involving a barge...

From http://www.delmarvanow.com/article/2...7080372/-1/ESN
The barge was towed away from the facility. After officials determined there was no damage to the northbound section, all traffic was diverted to those lanes just before 7 a.m.

Not to mention most modern bridges have barriers around the support pillars to protect them from debris and runaways.

[jester]

Colonel Ripley was a Marine advisor in Vietnam. He dropped the bridge at Dong Ha in 1972 Durring the Norths Easter Offensive. The bridge was a main link and major bridge as robust of the photos in the above pictures. It was the bridge on a highway that the Northern Forces were intent upon using to cross in a major offensive. This included a few hundred T-65 type tanks <hardly WWII class, closer to modern and what we would find in the T2K world.>

Ripley was one of two Americans assigned to a S. Vietnamese Bn who has exhausted their ammo but they had been given the order to "Hold and Die!"

Here is an exerp of the Colonels Obituary:

ANNAPOLIS, Md. � Retired Marine Col. John Ripley, who was credited with stopping a column of North Vietnamese tanks by blowing up a pair of bridges during the 1972 Easter Offensive of the Vietnam War, died at home at age 69, friends and relatives said Sunday.

Ripley's son, Stephen Ripley, said his father was found at his Annapolis home Saturday after missing a speaking engagement on Friday. The son said the cause of death had not been determined but it appeared his father died in his sleep.

In a videotaped interview with the U.S. Naval Institute for its Americans at War program, Ripley said he and about 600 South Vietnamese were ordered to "hold and die" against 20,000 North Vietnamese soldiers with about 200 tanks.

"I'll never forget that order, 'hold and die'," Ripley said. The only way to stop the enormous force with their tiny force was to destroy the bridge, he said.

"The idea that I would be able to even finish the job before the enemy got me was ludicrous," Ripley said. "When you know you're not going to make it, a wonderful thing happens: You stop being cluttered by the feeling that you're going to save your butt."

Ripley crawled under the bridge under heavy gunfire, rigging 500 pounds of explosives that brought the twins spans down, said John Miller, a former Marine adviser in Vietnam and the author of "The Bridge at Dong Ha," which details the battle.

Miller said the North Vietnamese advance was slowed considerably by Ripley.

"A lot of people think South Vietnam would have gone under in '72 had he not stopped them," Miller said.

Ray Madonna, president of the U.S. Naval Academy's 1962 graduating class, served in Vietnam as a Marine at the same time and said his classmate saved countless U.S. and South Vietnamese troops.

"They would have been wrecked" if the tanks had crossed, Madonna said. He said Ripley also coordinated naval gunfire that stopped the tanks from crossing at a shallower point downstream

>>>>>>>>

So, yes one man can do it. And the enemy were the ones who had the heavier weapons who could provide the supressing fire.

Now, with stealth, a team to do the work instead of one man, and luck, because if its behind enemy lines or in an area thought to be secure then it is possible it can be done.


Here is a link to an interview as well as a few pictures of the two bridges he took out:

http://www.youtube.com/watch?v=rdpQY_sCL7I


And here is a copy of his citation:

Navy Cross Citation, USMC Captain John W. Ripley, Advisor, 3rd Vietnamese Marine Corps Infantry Bn.

The Navy Cross is awarded to Captain John W. Ripley, United States Marine Corps, for extraordinary heroism on 2 April 1972 while serving as the Senior Marine Advisor to the Third Vietnamese Marine Corps Infantry Battalion in the Republic of Vietnam.

Upon receipt of a report that a rapidly moving, mechanized, North Vietnamese army force, estimated at reinforced divisional strength, was attacking south along Route #1, the Third Vietnamese Marine Infantry Battalion was positioned to defend a key village and the surrounding area.

It became imperative that a vital river bridge be destroyed if the overall security of the northern provinces of Military Region One was to be maintained.

Advancing to the bridge to personally supervise this most dangerous but vitally important assignment, Captain Ripley located a large amount of explosives which had been prepositioned there earlier, access to which was blocked by a chain-link fence.

In order to reposition the approximately 500 pounds of explosives, Captain Ripley was obliged to reach up and hand-walk along the beams while his body dangled beneath the bridge.

On five separate occasions, in the face of constant enemy fire, he moved to points along the bridge and, with the aid of another advisor who pushed the explosives to him, securely emplaced them.

He then detonated the charges and destroyed the bridge, thereby stopping the enemy assault.

By his heroic actions and extraordinary courage, Captain Ripley undoubtedly was instrumental in saving an untold number of lives. His inspiring efforts reflected great credit upon himself, the Marine Corps, and the United States Naval Service.

>>>>>>

And again, we it is possible. As was stated many factors do come into play. But, it is possible a small force can do the job quite handily.