In March 1941, Messrs. Wales and Whitehead wrote to the Australian Army Inventions directorate with a memorandum and booklet proposing the construction of an amphibian tank along with an armoring system designed to overcome the problems which existed in Australia at the time with the manufacture of heavy armor plate. An amphibian tank would suit much of the terrain in which Australian forces were fighting in the Far East. The terrain was often swampy or involved transport on and off islands, terrain unsuited to conventional tank designs.
The proposal did include two drawings. One of the proposed vehicle, and a second for the proposed armor plate, but sadly only the armor sketch survives, so it is hard to know exactly what this vehicle might have looked like. The proposal itself was very brief, just a two-page letter, but it was a well thought out and considered proposal, perhaps more than some of the inventions and ideas sent into the directorate during the war.
The overall shape of the vehicle is not known, but it was envisioned to be 18’ x 9’ x 8’6” (5.48m x 2.74m x 2.59m), and to use equalized spring suspension when traveling on land, which was seen as being particularly useful when traversing undulating ground. Displacement in water was stated to be 430 cubic feet (12.17 m3) for a vehicle measuring 18’ x 9’ x 8’6” (5.48m x 2.74m x 2.59m). This 12-ton vehicle was driven and steered by means of a controlled differential from an unspecified pair of V8 or similar engines. The main shafts for this design were positioned under the working floor level of the tank.
For protection this design was to use “2” (50.8 mm) thick armour plate equalling 80 lbs/sq.ft., but using a composite scheme consisting of armour plate and wood rather than simple steel armour plate. The metal layer of the armour was to be formed from rolled sheet and this laminated scheme was seen to provide ample protection and the potential to be reduced to 40 lbs/sq.ft. in the future. Several overlapping layers were used.
All invention suggestions submitted during the war were subjected to a technical assessment by a committee of experts, and the Wales/Whitehead Amphibian, being a very thoroughly drafted idea, received an equally thorough appraisal. In terms of vehicle weight, the 12 tons envisaged by the designers was seen as unrealistic when considering the proposed size of the machine with 2” (50.8 mm) of armor plate. The assessment considered that armor at 40 lbs. per square foot (195 kg / m2) was possible for the desired 12 tons weight of the vehicle, but that this would be barely bulletproof. A little confusingly though, under ‘Armour’, the evaluation contends that in terms of the scheme for 2” of armor that:
“I have no reason to suppose that the proposed armour is, in any way superior to a single homogenous plate…. It is not clear how the various laminations are bonded together”
This, then, means that the 2” of armor in the design was not just a single homogenous layer of armour but some type of laminated protection possibly accounting for the thickness and the relative light weight of the machine. The design had mentioned the use of wood, but the exact composition is not known.
In terms of floatation, the technical assessment looked at the design seeing it would displace less than half of the stated 430 cubic feet (12.17 m3) and were not able to figure out how the designers came up with 430 cubic feet. It was assumed that in order to do so, the track guards were to act as floats for the machine. This design was condemned as it was open at the bottom, allowing any trapped air to escape easily adversely affecting buoyancy. Either way, the floats would be easily pierced by enemy machine-gun fire. The designers had selected a pneumatic gun mounting to resist the gun recoil of “as large a calibre gun as possible”, but did not specify a particular weapon. The only weapons specified were the machine-guns which were to be Bren and Lewis guns positioned on the vehicle in locations to be determined by the military.
The inventors were vague as to exactly how the machine could enter the water at ‘launch’, suggesting some kind of lowering would be needed, but this obviously rendered the machine unsuitable as an easily launched amphibian.
For armament there was a complete disagreement between the inventors and the military experts. The inventors contended that it was the recoil length of the main gun which limited the firepower available whereas the experts concluded that this was not a problem and that the stowage of ammunition was a far bigger factor in determining the gun carried.
Following this assessment, the Army decided it was not worth further consideration, although the technical appraisal section of the department did have a few points of its own to raise which did not agree with those of the Army experts.
The technical appraisal section did not, for example, agree with the overall characteristics of the design, saying it was done to provoke some discussion so that it could be developed further for submission to the inventions board. Further, the low weight of the machine (just 12 tons) was as a result of the 40 lbs/sq.in. protection rather than the original 80 lbs./sq.in. and that the final weight would depend entirely upon the armor protection specified by the military – an entirely fair point.
Having made that fair point about the protection and weight, the section in the proposal did not accept the criticism of the scheme stating that “the writer [of the assessment] has no direct evidence of the efficiency of the proposed armouring” and that simple tests should be done to check out their idea. Here, this section also made clear that the proposed armouring scheme may have used more than just a lamination of steel or steel and wood. The appraisal of the design specifically referred to the armour on some British Cruiser tanks in the desert whose protection consisted of two armour plates with an airspace between them which suggests the armouring scheme involved some novel ideas about spacing between plates.
For floatation, again, the criticism was rejected, saying that the track guards did not play any part in floating the machine and the “the criticism does not apply being misconceived”
The Wales/Whitehead Amphibian Tank was considered to be well thought out and used some novel features. It had gained sufficient interest for the Army to consideration and the technical assessment did, in some regards, rate the vehicle as worthy perhaps of some further investigation.
The Army though was not interested, and was dismissive of the whole concept. Their final word on the matter was that it did not justify expenditure to investigate and that “in any case, there is no requirement, from the General Staff, for an amphibious tank”.
The Wales/Whitehead design then, regardless of what merits it may have had, was terminated and the drawings of the tank were sadly lost. All that remains of it are a few pages in a file. It is not even known who the two designers were as there is no information remaining to identify them.
Wales/Whitehead Amphibian Tank specifications
|Dimensions||18’ x 9’ x 8’6” (5.48m x 2.74m x 2.59m)|
|Total weight||12 tons|
|Propulsion||pair of V8 or similar engines – controlled differential drive|
|Armor||2” (50.8 mm) thick laminate steel/wood|
Australian Inventions Directorate File G177/701/1264 March – April 1941