Arleigh Burkes Class?

[kalos72]

Anyone know what being subjected to the thermal blast of a 2MT airburst would do ships of this sort?

Obviously there is alot of crew injuries/deaths to the thermal...would EMP wreck these newer ships or would they be pretty solid through a blast 10KM away?

Radiation poisoning an issue if they aren't in the fallout path?

[Legbreaker]

My (admittedly limited) knowledge is military ships are generally built to withstand a blast that far away. Provided the crew were expecting it, hatches and air vents closed, filtration systems working, etc, they should be ok at that range, even if they're in the fall out zone.

Once they're out of the area they'd have to do some serious decontamination and scrubbing though and there may still be some residual radiation after that. Anyone who stays inside should be safe enough.

Only those on deck, or not shielded by the superstructure would probably be injured (3rd degree burns, knocked off their feet if outside). Anyone on the bridge if shutters were not in place would likely be injured.
http://nuclearsecrecy.com/nukemap/?&kt=2000&lat=36.9642498&lng=-75.46443&hob_ft=0&casualties=1&fallout=1&ff=50&fallout_angle=99&zm=11

Sample point is 10.3 km from ground zero.
Overpressure: 4 psi
Maximum wind velocity: 62 mph
Initial radiation dose: 0 rem
Thermal radiation: 34.7 cal/cm²

[kalos72]

The scenario we are playing out is, the ship and crew were not expecting it. Many of the crew were on the rails, watching America drift away as they were on the maiden voyage on a new ship on April 1 in Houston.

Sailing past one, then two blasts as they leave Houston.

And the debate is, could that ship still function. Both from a crew loss/injury perspective and ship damage.

[Legbreaker]

The ship itself should be fine, although any papers, etc on the bridge would likely burst into flame and need to be extinguished. Anyone on the deck or bridge where they're not in shadow from the detonation would be severely burnt, but it's unlikely anyone would die.

The electronics are likely to suffer from the EMP, but again modern ships are built with that in mind so after switching out a few circuit breakers and the like should be back to near normal operation.

However with possibly critical crew injured and in the sick bay (which is sure to be overflowing with burn cases), it's unlikely the ship will be operating at anywhere near normal efficiency.

At least radiation at that distance doesn't appear to be a problem, unless they cop fallout...

[Targan]

And blindness, many of the crew would be temporarily or permanently blind, particularly if they were looking in the direction of the blast with LOS, or next to an exterior surface with a sufficiently high albedo.

[swaghauler]

Don't forget the "surge" from the airburst. It could easily be 50m high in the shallows depending on the depth of the water and the altitude of the airburst (if it was over water).

All US ships have been EMP shielded since the 80's and 10km is a bit of a reach for the incendiary blast from a 2KT airburst (which would extend about 3km). However, having the hatches open through the blast (which wouldn't directly reach the ship as a 2KT blast would generally only reach about 5km) could cause uncontrolled flooding. This in combination with a large surge (more common in shallow water rather than deep water) could swamp/capsize the ship.

The flash would extend to the horizon and could blind at 10km because it is an airburst (at probably 500 meters of altitude to maximize the blast).

Ok, I see you're talking about 2 MEGATONS (X2 the largest single warhead the Russians used)!

The Blast Effect would cause Minor structural damage to the ship (it will "toss" 150,000 lb railroad cars around at 5km).
The Incendiary Effect would possibly set fire to all flammable materials (including uniforms) and anodized aluminum would most likely lose its structural integrity (this can happen at just 250 degrees F).
The Radiation Effects would be fallout only.
The Surge could easily top 100 meters and would probably damage the ship (if the airburst was over water).

Also, keep in mind that if you're talking about multiple explosions which equal 2MT, things change. Wave Propagation occurs (and will be wider and taller) and Blast Range can be "amplified" by the intermingling blasts of multiple detonations. Incendiary Range would be reduced by the interaction of multiple blasts, though.

[Legbreaker]

I had thought about the wave when posting earlier but neglected to mention it. :/
If coming from the side it's absolutely going to be a major concern, from the bow or stern, not so much.

Are the warheads exploding simultaneously or in series? Are the effects (blast, light, etc) hitting the ship at the same time?

[kalos72]

Both nukes hit on the side, on land. The 2nd one is a 1.5MT and is about 20 minutes later as the ship travels out of Houston.

I am talking about the Baytown and then the Texas City hits...

[Legbreaker]

In that case the ship is almost certainly battened down for the second hit with nobody on the deck and blast shutters in place on the bridge, so it's unlikely they'd be any further injuries at that point from the blast.
http://nuclearsecrecy.com/nukemap/?t=ed881faac6d0d7bc30888cb2e3623787

Where was the ship departing from? My best guess is the ship would have been stern on to the first blast, and hit from the starboard by the second.
Also, once the first nuke hit, the Captain (or whoever is in charge if he was wounded) would likely order the maximum possible speed to get out into the ocean and away from a possible follow up warhead.

[kalos72]

That makes sense but would they really try to put to sea with large amounts of wounded or dead?

Wouldn't they try to find someplace local that they felt was safe to dock up and help with the wounded?

The story line is they were heading to Galveston to pick up some passengers after taking fuel and cargo on in Houston.

[Legbreaker]

Well the city just got nuked. What help are they going to get there with the tens of thousands of other wounded already clogging the medical facilities (if any are left) before they can even dock? There may even be crowds heading to the docks looking for a way out of the city, and willing to kill for a spot on the ship.
Being a military vessel, they've probably already heard the first reports of strikes in other areas as well, so it's not a huge mental leap to consider follow up strikes where they are as well, especially given the facilities in the area they're in.
Also, if they were stern on to the first blast the bridge is very likely to have been spared the worst of it (a few casualties who may have been exposed through the rear facing windows and hatches). The bridge crew would be amongst the most important people on the vessel in the initial stages and it will take some time for them to assess the damage to ship and crew. While that assessment and initial reaction was going on, it makes sense to put as much distance between ground zero and the ship - they're already in poor shape, don't need fallout adding to their woes.

Once they were a few dozen miles to sea they'd be in a better position to assess their situation. Are they able to cope with their own casualties? What are their orders in this eventuality? Does their mission preclude assisting survivors? How widespread is the attack?
A lot of questions to try and find answers for before either moving on, or heading back in.

[swaghauler]

Well the city just got nuked. What help are they going to get there with the tens of thousands of other wounded already clogging the medical facilities (if any are left) before they can even dock? There may even be crowds heading to the docks looking for a way out of the city, and willing to kill for a spot on the ship.
Being a military vessel, they've probably already heard the first reports of strikes in other areas as well, so it's not a huge mental leap to consider follow up strikes where they are as well, especially given the facilities in the area they're in.
Also, if they were stern on to the first blast the bridge is very likely to have been spared the worst of it (a few casualties who may have been exposed through the rear facing windows and hatches). The bridge crew would be amongst the most important people on the vessel in the initial stages and it will take some time for them to assess the damage to ship and crew. While that assessment and initial reaction was going on, it makes sense to put as much distance between ground zero and the ship - they're already in poor shape, don't need fallout adding to their woes.

Once they were a few dozen miles to sea they'd be in a better position to assess their situation. Are they able to cope with their own casualties? What are their orders in this eventuality? Does their mission preclude assisting survivors? How widespread is the attack?
A lot of questions to try and find answers for before either moving on, or heading back in.

I agree. As counter-intuitive as it may seem, deeper water is the better option. As the water gets deeper, the waves created by the blast get smaller (because the blast's energy is dissipated by the larger volume of deeper water). The fall out will have a harder time falling out to sea due to the higher pressure over the water (from the incendiary blast creating steam). And if no warning were given, a US warship might assume SLBM and go looking for a little "payback" (provided it wasn't badly damaged).

[Targan]

That makes sense but would they really try to put to sea with large amounts of wounded or dead?

Wouldn't they try to find someplace local that they felt was safe to dock up and help with the wounded?

No doubt there were SOPs in place for just such an event in real life. Do we have any Navy officer vets among our members?