Pykrete and Project Habbakuk

[Mossie]

Gregs request got me thinking.  I got 'My Tank is Fight' by Zack Parsons for Christmas & it details several truly nuts WWII projects.  One of most mind numbing was HMS Habbakuk, a crazy project to build a giant aircraft carrier/marshalling platform from ice!  The details are on Zack Parsons site Something Awful:
http://www.somethingawful.com/booklist/august05.htm

These are the only two pics I can find & of quite different configurations, I don't know if these are helpful enough?  I'd love to see it brought to life!


Drawing & General Arrangement diagram.


Drawing, including USS Nimitz & USS Missouri for scale.

[Archibald]

http://www.secretprojects.co.uk/forum/inde...pic,1719.0.html

[B777LR]

http://www.combinedfleet.com/furashita/habbak_f.htm

The Soviets wanted it as an offshore prison ship in Siberia, but the Americans took it across the Polar Route to Alaska to use as a ready-made housing project for Eskimos

 

[RP1]

I was working on it, but never got very far:



I couldn't figure out how to detail it, but that more detailed figure you show should be useful.

I'm sure I've been to Patricia lake.  I didn't know about the little bit of whiff naval history there!

RP1

[The Rat]

Ah yes, good old Pykrete! Next time we get a cold snap I'll gather some old grass clippings and try to make some.  

There is a story that Churchill was given a chunk, which he took into a hot bath with him to see if it really would resist melting. Now there's a diorama that would implant a mental image of questionable taste...    

[Madoc]

Mossie & all,

I think a lot of the depictions of the Habbakuk err in rendering it as either just a super large standard aircraft carrier or as some ice cube looking thing that's been chipped into a vaguely aircraft carrier shape.

From what I've read of the proposed design, the final shape of it would be pretty streamlined - i.e. no iceberg appearance to it at all.  The vessel's hull would also be entirely clad in plywood sheets thus furthering the smoothness of the surface.  The Pykrete would be formed in large blocks and that'd be laced with cardboard tubes through which the ship would pump chilled air to keep the Pykrete frozen.

The actual "aircraft carrier" portion of the vessel would be made out of steel constructed in a standard way and designed to sit in the middle and center of the whole Pykrete assembly.  Think of a really big barge sitting atop an even larger expanse of smoothly covered ice.  Thus there'd be no aircraft carrier "island" stuck off on one side of the ship's hull - there'd simply be no structure there to support its weight.  Instead, it'd be more like an airfield control tower emplaced atop the Pykrete's upper surface.

The central structure would contain all the habitation areas, aircraft elevators, machine shops, armory, fuel bunkerage, generators and the all important refrigeration plant.  All within its central position and all behind some very heavy insulation so that the normal operating temps of the inhabited spaces would not start melting any of the Pykrete around it.

As to how they'd mount all those propulsion units I've no clue.  They couldn't very well just bolt them to the Pykrete as the stresses generated by the engines would tear them off even that mixture of ice and wood pulp.  So, there'd have to be some sort of load bearing structure onto which those propulsion units got attached.

I also recall that there were plans to use such vessels even out in the Pacific and in equatorial waters there!  They figured that the ocean water's temp was low enough that the refrigeration plants would be able to stay well ahead of the warmer clime's effect.

Now, imagine that the Allies had produced not just one of these beasts but several.  A couple ranging across the Atlantic allowing for B-24's to operate from them as well as several out in the middle of the Pacific allowing B-29's to use them.  And then imagine the teams of repair workers who's job it would be to smooth over the chunks in the hull that'd be getting blasted out by all the torpedoes being fired - harmlessly - at such ships by all the Axis subs!

Madoc

[RP1]

My CG model matches the dimensioned schematic given in Wallace, W J "Habakkuk", Warship Volume V, 1981.  This shows that the vessel was not going to be very streamlined at all - there would be no point for a vessel of her size and low speed.

These figures show a basic island structure, but you are correct that this would have been problematic to incorporate structurally, unless it was mounted on a "raft" that distributed the load.  The issue of how to attach the propulsion motors seems never to be mentioned...

RP1

[Mossie]

Personally, the why's & wherefore's don't worry me too much on this one, more the sheer scale!  The first pic I've provided, although poor quality, gives some idea to it's structure, which Mado mentioned.  There appears to be a large hollow within the pykrete, which holds the stucture of the ship.  The engines seem to be attached to this structure via long beams, which I would imagine would then be supported by the pykrete.  As far as an isalnd goes, it doesn't seem to be attached to the internal stucture, although maybe foundations could be dug (or cast?) similar to a building?

[Archibald]

Mossie & all,

I think a lot of the depictions of the Habbakuk err in rendering it as either just a super large standard aircraft carrier or as some ice cube looking thing that's been chipped into a vaguely aircraft carrier shape.

From what I've read of the proposed design, the final shape of it would be pretty streamlined - i.e. no iceberg appearance to it at all.  The vessel's hull would also be entirely clad in plywood sheets thus furthering the smoothness of the surface.  The Pykrete would be formed in large blocks and that'd be laced with cardboard tubes through which the ship would pump chilled air to keep the Pykrete frozen.

The actual "aircraft carrier" portion of the vessel would be made out of steel constructed in a standard way and designed to sit in the middle and center of the whole Pykrete assembly.  Think of a really big barge sitting atop an even larger expanse of smoothly covered ice.  Thus there'd be no aircraft carrier "island" stuck off on one side of the ship's hull - there'd simply be no structure there to support its weight.  Instead, it'd be more like an airfield control tower emplaced atop the Pykrete's upper surface.

The central structure would contain all the habitation areas, aircraft elevators, machine shops, armory, fuel bunkerage, generators and the all important refrigeration plant.  All within its central position and all behind some very heavy insulation so that the normal operating temps of the inhabited spaces would not start melting any of the Pykrete around it.

As to how they'd mount all those propulsion units I've no clue.  They couldn't very well just bolt them to the Pykrete as the stresses generated by the engines would tear them off even that mixture of ice and wood pulp.  So, there'd have to be some sort of load bearing structure onto which those propulsion units got attached.

I also recall that there were plans to use such vessels even out in the Pacific and in equatorial waters there!  They figured that the ocean water's temp was low enough that the refrigeration plants would be able to stay well ahead of the warmer clime's effect.

Now, imagine that the Allies had produced not just one of these beasts but several.  A couple ranging across the Atlantic allowing for B-24's to operate from them as well as several out in the middle of the Pacific allowing B-29's to use them.  And then imagine the teams of repair workers who's job it would be to smooth over the chunks in the hull that'd be getting blasted out by all the torpedoes being fired - harmlessly - at such ships by all the Axis subs!

Madoc

Sounds fascinating, truly an idea for a James Bond movie villain!!!

Would this idea be interesting today ? Considering  refrigeration plants technology has progressed enormously since the 40's...  maybe this could be an interesting solution to build a low-cost carrier ?

The Pykrete would be formed in large blocks and that'd be laced with cardboard tubes through which the ship would pump chilled air to keep the Pykrete frozen.

Rafa, where are you ? Here's a building method for us...

[B777LR]

The Pykrete would be formed in large blocks and that'd be laced with cardboard tubes through which the ship would pump chilled air to keep the Pykrete frozen.

Rafa, where are you ? Here's a building method for us...

Blocks of glue mixed with saw dust? Ewww

[Mossie]

I've had a look in 'My Tank is Fight' & it seems the cladding would have been made from cork, which is at odds with the Wikipedia article that mentions fibreboard.  Doesn't matter much for modelling I suppose!

Wiki has an article on Pykrete, plus an interesting section on a test they did on Mythbusters which has been added since last time I looked.
http://en.wikipedia.org/wiki/Pykrete

Looking forward to seeing the pics of the hull!

[tinlail]

I haven't study the source material, so I am just talking about what I think is a good ideal. I would suggest that the working Habbakuk should be able to refinish itself, so I would suggest that the notion of cladding the edges is better done with a system of spraying on a new coating. Some examination of modern concepts of mobile sea basing might give a good notion of what capabilities Habbakuk could have. Perhaps to support the unexpected Norway landings.

[seadude]

Not sure if this topic belongs here. If it's in the wrong forum, then can a Mod move it to the correct one? Thanks.

As some people are already aware of, I'm currently in the process of constructing a Habbakuk model ship.
http://en.wikipedia.org/wiki/Project_Habakkuk
http://en.wikipedia.org/wiki/Pykrete
As I've been researching this subject, I've gotten very curious about the following: If a real Habbakuk type ship had been built in WWII, then how do you think it would have stood up against German or other Axis nation guns, bombs, and torpedos? What would have been effective and what wouldn't? Could a Habbakuk ship take a severe beating and still keep floating? According to research I've done, the hull walls, bottom, and top were going to be 40 foot thick pykrete. 




***merged with original Habbakuk discussion***--jjf

[Hobbes]

This is speculation, but I'd expect a 40-ft wall of ice to be pretty much invulnerable to everything except bunker busters, maybe 16" AP shells. Torpedoes are another matter. Detonating a torpedo underneath the ship would break it. The pieces still float, though. If you have some sort of structure in place to keep the pieces together, you can use the existing refrigeration machines to repair the ship (freeze the pieces together again). 

[The Rat]

Pykrete was pretty impressive stuff, but I'm sure some bright boffin would have come up with a way of defeating it. But go for it, I've had plans for a while now for a 1/144th Habakkuk but the thought of buying, building, and detailing a bunch of aircraft for it gives me the cold sweats!