Editing Project Habakkuk (section)

=== Variants ===
Naval architects produced three alternative versions of Pyke's original concept, which were discussed at a meeting with the Chiefs of Staff in August 1943:
* Habakkuk I (soon discarded) would have been made of wood.
* Habakkuk II was closest to the COHQ model and would have been a very large, slow, self-propelled vessel made of pykrete with steel reinforcement. The size would have been a length of 2000 feet and a width of 300 feet.<ref>{{cite conference |date=August 18, 1943 |title=Memorandum by the British Chiefs of Staff |url=https://www.jcs.mil/Portals/36/Documents/History/WWII/Quadrant3.pdf |pages=188 |access-date=May 3, 2024 |book-title=Quadrant Conference}}</ref>
* Habakkuk III was a smaller, faster version of Habakkuk II.
<gallery mode="packed" heights="200">
File:Habakukk aircraft 02.jpg|Aircraft carrier drawings.
File:Habakukk aircraft 03.jpg|Cross section, showing 40 ft (12 m) thick walls made of ''[[pykrete]]''
</gallery>

[[Charles Portal, 1st Viscount Portal of Hungerford|Air Chief Marshal Portal]] asked about potential bomb damage to Habakkuk III, and Bernal suggested that a certain amount of deck covering might be ripped off, but could be repaired by some kind of flexible matting. It would be more difficult to deal with bomb holes in the centre portion, though the roof over the aircraft hangars would be made blast proof against 1,000&nbsp;kg bombs. Bernal considered that no one could say whether the larger Habakkuk II was a practical proposition until a large-scale model could be completed and tested in Canada in the spring of 1944. He had no doubts about the suitability of pykrete as a material, but said that constructional and navigational difficulties remained to be overcome.<ref name=brown>{{cite book |last=Brown |first=Andrew |title=''J.D. Bernal: The Sage of Science'' |publisher=[[Oxford University Press]] |year=2005 |isbn=0-19-851544-8}}</ref>

The final design of Habakkuk II gave the ''bergship'', as it was called, a displacement of 2.2 million tons. Steam turbogenerators were to supply {{convert|33,000|hp|abbr=on}} for 26 electric motors mounted in separate external [[nacelle]]s (normal, internal ship engines would have generated too much heat for an ice craft). Its armament would have included 40 dual-barrelled 4.5" DP (dual-purpose) turrets and numerous light [[anti-aircraft warfare|anti-aircraft]] guns, and it would have housed an airstrip and up to 150 twin-engined bombers or fighters.<ref name="perutz" />