The outcome of this project is an illustration of a rule of thumb from materials science: many solid materials begin to lose their mechanical properties at about half their absolute melting point. This is why (for example) ordinary steel should not be used above about 550 C; there's too much creep.
I thought the "failed" result of the project was more due to economic factors, and the reduced need due to other actions in the war meaning a waterborne carrier was less useful. Not some issue with the mechanical properties of pykrete. If the tested properties were already past that 1/2 absolute temperature point and considered acceptable, it doesn't really matter what the behavior would have been at less than that.
"The full-sized ship would also need to have a range of 7,000 miles, support heavy bombers and be torpedo-proof. It was to be over a mile in length, weigh as much as 2.2 million tons and require as many as 26 electric motors to move and steer across the ocean."
That's a crazy target growing out of "cheap to produce aircraft carrier"
I'd add in that ot would have been difficult to operate as well.
For starters aircraft carriers face into the wind for takeoff and landing. So that means either engines for maneuvering (noted in the article) or support vessels. Presumably support vessels are vulnerable so not in the picture.
It would sail like a pig ‐ with 90% underwater it'll pretty much go where the current goes. And very slowly.
I imagine the engines would either be small (slow maneuvering) or large (need fuel etc).
Once you need significant fuel you need to store it. Plus of course all the men, and their stores. And a lot of this doesn't like freezing temperatures.
To be useful the thing presumably has to be far from land, presumably closer to the enemy. So the enemy deploys a bunch of anti-aircraft ships to basically follow the thing. Returning aircraft are sitting ducks.
I'm no mechanical engineer, but none of this makes any sense to me at all.
I'm even less an admiral or air marshall but I dont see any tactical or strategic advantage here either.
> I'm even less an admiral or air marshall but I dont see any tactical or strategic advantage here either.
Not disagreeing with your main points at all, but from a strat/tac point of view, up until later in the war, there was an air gap in the Atlantic where German U-Boats didn't have to worry about a significant air threat from the Allies. A large airfield parked mid-Atlantic might have significantly improved Allied air coverage, and helped reduce the stunningly bad shipping losses they were experiencing.
Exactly, and we also developed longer range aircraft and better anti-U-Boat weaponry. Hence my observation regarding the air gap that existed earlier in the war (not that the bergship would have been ready then)
If your runway is a mile long you can tolerate a lot more crosswind component (or, more precisely, aren't so desperate for every know of apparent headwind).
As I understand it, they found out they needed to refrigerate the ice to keep it from creeping too much, and this increased the cost too much for the idea to work.
The US did make some vessels out of concrete because of constraints on steel production. A famous example was a barge in the Pacific (I think at Ulithi?) that was devoted to making ice cream.
The article seems to make it clear that the refrigeration requirement was known from the start (how could it not be?) but that the amount of steel required had to be increased substantially to avoid creep in the ice.
Can you expand on this comment in the context of ice/water? It implies ice changes behavior at about 140K, but that isnt close to a phase change boundary, so what would you expect to be seeing here?
Also same with cold . Up north it’s a fools errand to run heavy machinery past about -55c. The steel develops tiny fractures, and six months later the ten ton loader will just break in half.
"Strength loss for steel is generally accepted to begin at about 300°C and increases rapidly after 400°C. By 550°C steel retains approximately 60% of its room temperature yield strength, and 45% of its stiffness. At high temperatures, steel is also subjected to significant thermal elongation, which may lead to adverse impacts, especially if it is restrained."
The material they used (water mixed with wood, frozen) is called pykrete.
> Blocks of ice containing as little as four percent wood pulp were weight for weight as strong as concrete; in honor of the originator of the project, we called this reinforced ice "pykrete". When we fired a rifle bullet into an upright block of pure ice two feet square and one foot thick, the block shattered; in pykrete the bullet made a little crater and was embedded without doing any damage. My stock rose, but no one would tell me what pykrete was needed for, except that it was for Project Habakkuk.
Unfortunately it turned out to be basically impossible to keep a ship-sized block of it frozen, and modern attempts at replicating it have found the strength claims to be a bit "optimistic".
This is one of those “so cool yet so silly” brainstorms that I’m grateful someone was audacious enough to entertain. I’m both relieved and saddened that it never came to fruition.
There’s a word, chindogu, to describe things that are less than useless. In some sense this project engendered more problems than it solved. Like so many other attractive brainstorms.
This reminds me of my favorite part of this story. In 1943, the first Quebec Conference between the US and UK military brass was a very contentious and heated affair, with the top generals and admirals on either side almost coming to blows. At one point they all dismiss their aides and go into a closed session, and Lord Mountbatten takes this opportunity to brief everyone on Project Habbakuk, using some samples of pykrete to demonstrate its resilience compared to ordinary sea ice. At one point in the demonstration, he draws his service revolver and fires at the pykrete.
Now, both the US and UK aides and staff officers are outside the room where this is happening, and they don’t know what’s going on, but they all remember how heated the earlier discussions were, so naturally, when they start to hear gunshots from inside the room, they all panic and assume the worst and burst through the door. Fortunately, everyone was unharmed—the bullet ricocheted off the pykrete and embedded itself into the wall, only grazing the trouser leg of Ernest King.
Pykrete is one of those things that makes sense in theory, but in practice and from a practical perspective just isn't great.
There aren't a lot of places in nature where you have tons of trees and easy to get ice. So a society would never default to pykrete because those two things tend to be the opposite of each other. Its a somewhat unnatural thing to do.
Industrialized societies just can make steel and steel doesnt start to soften until 500-600 degrees F. There's no need for a 24/7 refrigerator power plant to keep steel from melting. Steel also is strong and rigid. Steel is of course still used today for both war and civil ships, and has been since the day it became technically and economically feasible to do. Its really hard to beat steel. This project has some nice technical merits and pykrete itself is interesting, but it just doesnt seem to ever have a practical use.
> There aren't a lot of places in nature where you have tons of trees and easy to get ice.
I take issue with this - there are vast swathes of canada, sibera, and northern europe where this is the case. I would say however finding all three year-round near liquid water may be harder, although not exactly an insurmountable challenge compared to say, moving quarried rock 5 miles to build a house
Think most peoples gut reaction would be that it would melt.
But
"it took three hot Canadian summers for the test vessel to completely melt."
Seems like in north sea, it would have worked and probably would have happened if it wasn't for un-related changes like airfields and re-fulling planes.
That makes me wonder if that guy that was killed by his girlfriend while attempting a dumb stunt, using a encyclopedia as ballistic shield, would succeed if he had soaked the book in water and put it in the freezer overnight, beforehand: https://www.dailymail.co.uk/news/article-5878953/Prosecutors...
If memory serves there was a plan to invade the Azores in WW2 which would have been immensely ironic.
After WW2 the US was gracefully handed over a few islands to serve as aircraft bases. The Chinese still lack such soft power so they have to make their own islands.
What if, instead of building a full carrier out of pykrete, you instead build very simple pykrete ships that follow around the outside of a carrier group to add a layer of protection from torpedoes and sea drones?
> By definition, a convoy consisted of two or more merchant ships under the escort of one or more warships, but typical transatlantic convoys during the war consisted of large numbers of ships—the largest composed of 166, with typical convoys consisting of 45 to 60 ships—steaming in 9 to 12 columns with 1,000 yards between columns and 600 yards between ships in the individual columns. Because of their extra vulnerability, tankers and ammunition ships were placed in the innermost columns, and the convoy commodore in charge would be in the lead ship in the center column.
That is a lot of attack surface. But they kind of already do your idea, just with metal ships carrying goods.
Yeah makes sense, if you already have metal ships carrying goods there is no need to make additional ships just for protection. I suppose there could be an economic advantage if the pykrete ships can be made significantly cheaper and faster than the cargo ships.
It makes me wonder why Ukraine is so successful in the black sea with their sea drones vs. the Russian navy? Why wouldn't Russia have ships or something else blocking their battleships at port? It seems Ukraine is able to sink everything with ease at the moment.
I am sure that it has been presented as wester aggression in some circles... but it is not really a great example if look at the whole story:
This was (very) late in WW1 and the Russian Revolution turned a solid ally of Czarist Russia into a mess of waring groups more-or-less causing the Russian front of that war to more-or-less collapse. The Whites looked more like they would be in favor of continuing the war, while the Reds explicitly made a pease that did not include the west (Treaty of Brest-Litovsk).
And the U.S. had been supplying Russia with arms, with many of them still sitting in warehouses in Murmansk. There was legitimate fear that German forces (who had just invaded Finland) would take this large stockpile of arms, and combined with the lack of an eastern front, that would turn the tide of war. From the Western perspective they needed to do something.
Please remember that Russia was in Civil War at this point, and pretending it was clear who was (or rightfully should be) in charge of things is not realistic. The West chose a side (the one more likely to favor it), and it turns out that was not the winning side. If the other side had won history would be very different (that is a safe statement, anyone who gives you more is just guessing), but that invasion probably would have been welcomed if it had turned out different.
With 20/20 hindsight it was wrong to do more than grab the arms shipments and leave: the Russian Civil War should have been an internal matter.
But pretending that the West was just being aggressive, or trying to take over Russia is a bit disingenuous.
you are right that there was serious conflict.. please note that I did not "pretend" anything.. as a serious place for discussion and learning, let's agree here at YNews to apply information tools and good reasoning on this important topic.
I am not taking sides. Historical documents show that the Germans in WW II bombed the city with ferocity and an intent to destroy it completely. Of course that was a different political era, yet it is relevent today.
Russian civil war was not an internal matter from the very beginning considering that multiple foreign forces conspired to make it happen. Also as we have learned it should have not been an internal matter considering the vast humanitarian losses caused by the communist terror that followed.
So perhaps you meant to say that Russian civil war should have been an international matter?
Btw. this is a common Russian propaganda talking point how Russia (a largest remaining imperial and colonist power) has never been aggressive and has only been "defending" itself.
A larger problem is that for some reason American conservatives have been starting to pick up many those Russian propaganda talking points, designed to undermine the American morale.
This concept could be done today with newer materials such as mylar film and polystyrene to keep the sun at bay.
Although a YouTuber would be able to do it for internet likes, in reality, when the horse manure gets real, every aircraft carrier is a dead duck when the enemy has hypersonic missiles.
