As the author of the original post linked to on the warships board re. Project Tentacle, I thought I would post the whole of the original (I have emboldened the relevant bit) :





Project Tentacle (sort of)



Well as I was popping into the PRO today, I put “Tentacle” into the search catalogue and got “ADM 116/4882” which is staffnotes covering Project Habbukuk and Tentacle.



HEALTH WARNING – This is only one file and is only part of the story, still it is interesting.



First, the file covers minutes and minor correspondence from June to November 1943



The vast majority of the file covers Habbukuk, only two pages and one refernce to “Tentacle” is in the file.



I learnt a lot more about Habbukuk, it wasn’t just the pyecrete vessel, it was a whole range of options.



The initial specification was for a floating airfield due for delivery by Spring 1944 with approximate dimensions 1,500 ft by 250ft and capable of being towed at approx. 2 knots.



Later the spec changed in various iterations to increase the length to 2,000 ft, width to 300 ft and a self-propelled speed of, variously, 7 and then 10 knots, all depending upon the proposed function of the vessel.



Five different vessel types were proposed ;



1: Pure Ice



2: Pykrete



3: Steel (est. 50,000 tons)



4: Concrete (see below)



5: Timber (quoted at different places at 47,000 tons and 100,000 tons)



Originally the Timber version was recommended.



In relation to the concrete version, two types (sub-types ???) are mentioned, Habbukuk II intended as a staging post for bombers and transports, 2,200 ft long with a speed of 7 knots. Habbukuk III was meant as support for amphibious landings, operating fighters and light bombers, 1,000 to 1,200 ft long with a speed of 12 knots.



----------------------------





Well that’s Habbukuk, what about Tentacle ?



Tentacle is mentioned right at the beginning of the file XXXXXXXXX



In addition there is a memo dated 10th November 1943 from “J.S.M. Washington” addressed to “W.C.C. London”.



It notes that “flying test on steel pontoon type 1800 ft long on November 6th highly successful. …….. 16 Hellcats, 9 Avengers and 9 Dauntless landed in 20 minutes without practice ……… 33 planes took off in under 14 minutes …… Outboard motors at 2 diagonal corners successful in keeping platform head to a changing wind which increased to 10 knots. Anchor cable was brought to centre of contraption. …… Strip rigid and free from tendency to wave motion under load. Has withstood waves up to 4 foot high with 45 m.p.h. wind for three days. ……. All U.S. and British observers very pleased with results. ……. It seems doubtful however if even with the best boat drill it could be assembled in much under two days, and this makes its tactical use questionable.” The last comment reads “11. We have encountered obstacles and obstinacy in the way of HABBUKUKS made out of cement.”



It is also noted that films were taken of the test.



-------------



The comment earlier in the file is a sort of “index” to the file and reads (in its entirety :-



“Tentacle Airfield

(Floating Steel Pontoon)

Reports of flying trials conducted in U.S.A.

Anglo/US co-operation



------------------------------------





Make of that what you will.





I never did find out any more about project tentacle.



.