The accounts of
the events of August 8th and of the preparations for the battle are
highly evocative. Zero hour for the attack was fixed at 4.20am on the
morning of the 8th. As the brigades and their vehicles and enormous
amounts of materiel were moved up to the jumping-off points in the
preceding days and nights meticulous precautions were taken to ensure
that the Germans had little or no warning of the coming blow. Troops
were told to move in small seemingly random groups by roundabout ways.
Aeroplanes were flown over the area so that their noise would drown out
the sounds of the tanks and lorries moving into position.
Diversionary attacks were carried out to confuse the enemy.
On the night of 4th/5th
August 1918 the 16th battalion was moved into bivouacs on the banks of
the river near Vaire-sur-Corbie (sic). Here it remained until the night
of 7th/8th August when it was moved immediately after dark to the first
forming-up place between Vaire-sur-Corbie and Hamel. (Taken from the
Diary of the 16th Battalion).
During the night before zero hour orders were whispered rather
than
barked. Accoutrements and anything other items which clinked or
rattled were muffled. Horses were calmed to prevent them from neighing.
Talk was kept to a minimum to avoid information being picked up by
German listening posts. The troops sat quietly smoking their Woodbines
and preparing for the great event. According to the contemporary
accounts morale was excellent.
At Zero Hour a thick fog lay over the area and as the battalions moved
forward from their jumping off points, heralded by a massive
bombardment of the German positions, they had the greatest of
difficulty keeping in touch, maintaining the required positions
relative to each other and making out the German positions ahead of
them which they were to attack. As usual in an assault of this kind the
Allied artillery, which was trying to "walk" its shells forward just
ahead of the advancing troops to soften up the German positions
(see the lines of trenches on the above map), was having difficulty
ascertaining the positions of the Allied troops in the fog. Conversely,
of course, the fog gave the infantry excellent cover as they advanced,
in many cases surprising German units as the Australians overran (or
stumbled into
?) their positions. One account in the Diaries mentions that a group of
German officers was surprised at breakfast !
The fog cleared later in the morning but was to hamper the attack
considerably in the first few hours. Nevertheless, the advances made by
10am that morning were prodigious. A contributory factor was surely the
limited resistance of the German troops. The Diaries of August 8th and
the succeeding days are full of accounts of German troops surrendering
in large numbers to be marched back to the prisoner-of-war facilities
in the rear with smiles and other expressions of relief on their faces.
The Australian troops reported that the fire from German artillery,
machine guns and other heavy weapons was intense but the resistance
melted as soon as the fighting at close quarters began. One gets a
feeling from these accounts that the majority of the German troops were
quite simply exhausted by 4 years of war.
Infantry Company D, of which Thomas Casey and Ivan Gurthrie were members, was
assigned to the third phase of the attack (between the RED and the BLUE
objective lines on the above map). They attacked on foot and in
infantry-carrying Mark V* tanks. These
tanks were not battle tanks as we know them nowadays but rather
armoured personnel carriers.

Mark V tank
The
abovementioned http://www.awm.gov.au/histories/first_world_war/volume.asp?levelID=67892 when referring to the tanks says in a
footnote on p.68 “Like those allotted to other brigades eight of
these tanks carried as passengers 8 officers and 112 other ranks of the
AIF with 10 Vickers and 16 Lewis guns, an average of 15 passengers each
beside the normal crew of eight". There was a ninth tank in reserve.
They were by all accounts underpowered, unreliable, cramped, hot, noisy
and fume-filled even before they were shot at. The Diaries describe
how Company D moved forward to their assigned part of the assault
in the fog and under artillery fire, with the officers in the tanks
peering out of little slits and trying to find the way and "steering"
the drivers by tapping on their shoulders. Time and again they
would find themselves moving up a hill or over terrain which the tank,
with its underpowered and overheating engine, could not manage and they
would have to turn back and try another way. For much of the advance
the infantry preferred to walk beside their tanks and risk the enemy
fire rather than endure the discomfort inside. If I have
read/interpreted the Diaries correctly, many of Company D's tanks had
quit by the time the unit reached the third phase of the attack to
which they had been assigned.
For the assault phase between the RED and the BLUE lines the
Battalion had only 4 tanks left and another tank, a Mark V, was picked
up to accompany them. Up to the RED line the casualties had been few
but between the RED and BLUE lines, the segment to which Thomas Casey's
and Ivan Guthrie's 'D' Company had been assigned, they mounted under the withering fire
from the German positions on the hill on the opposite banks of the
Somme. Four tanks were put out of action by the German guns
before reaching the BLUE line, one when crossing the RED line, two in
Q.18.c, and the fourth in Q.17.b (these map coordinates can be
found on this
map). The fifth got as far as the BLUE line near Mericourt
but was there put out of action and most of the crew were killed. This
latter tank was probably the one which carried Thomas Casey and which
he abandoned to advance with his Lewis gun.
The casualties between the RED and BLUE lines amounted to 40% of the
Battalion strength and included Thomas Casey.
Captain W.J.Lynas, D.S.O., M.C., O/C of 'D' Company, wrote the
following account of the advance of his tanks which contained
Thomas Casey and Ivan Guthrie (they may have been in the same tank but we cannot be certain of this):


To allow a better understanding of
this account of the assault I have transferred the map references to
the following map
of 'D' Company's movements on the morning of the 8th of August.
Tantalisingly, it is not clear
exactly which tanks Thomas Casey and Ivan Guthrie were in (they may have been in the same one). Note the statement that
"......all ranks on coming out of the machines were incapable of any
movement for varying periods up to 3 and 4 hours...". Possibly the
occupants of the tanks were poisoned with carbon monoxide in addition
to all the other vicissitudes they had to endure.
Another summary of the battle has been published by Philip
Eagles.