Part II: The Fortress Holland
The battle with the airlanded troops in the Fortress Holland would peak at the Island of Dordrecht on the third day of the invasion. It would develop into a very complex and interesting series of events. We shall therefore first reintroduce the opposing forces in a comprehensive overview.
After the extended elaboration on the battle for the Island of Dordrecht, the other events elsewhere in the Fortress shall be addressed.
Introduction and status quo
The Dutch Light Division was a mobile division. Originally it had been designated as the dynamic Field Army unit in defence of the large gap to the southwest of the Peel-Raamline. That particular assignment had required the unit to be highly mobile and dynamic, which features used to be the premise of units designated as 'light' in those days.
To Dutch standards the division indeed matched the requirements in respect to mobility. The strength of her ranks and quantity of her equipment left however much to be desired. First of all the division was still being built up when the war broke out. Her infantry regiments, for example, had shortly before the German invasion received their third battalions, which were incompletely filled and moreover lacked much of the modern equipment the other battalions were equipped with. Prior to war break-out the Division had been stripped of all its  modern armoured cars and one of its motorized units [Regiment Motorized Hussars]. These had been assigned to air field defences and reserves near The Hague. This permanent detachment of significant forces could nevertheless not be seen out of the context of the revised strategy in which the Light Division would form a strategic reserve within the Fortress Holland rather than a dynamic Field Army unit.
The division artillery was weak. Only 16 guns of 7,5 cm were available. The two motorized six gun batteries of light field guns [5,7 cm] had been re-assigned elsewhere in the south. The foreseen battalion of medium field guns had not yet phased in. Furthermore, in the morning of the 10th when the Division was ordered to evacuate Brabant, it had to leave behind the second and last motorized hussar regiment that was engaged in the battle at Mill. It would only partially return to the division main force during the days that followed.
All in all the divisional strength contributed to a number of about 8.500 men at 10 May. Of this modest strength about 3.500-4.000 men would be transported to the Island of Dordrecht, whereas a force of about 3,000 men would take positions around Alblasserdam.
About 1.500 men Dutch garrison troops were encamped in the city Dordrecht itself when war broke out. With exception of about 100 men, these troops were of low combat value. The majority were recruits or auxiliary troops such as cooks, instructors, medical troops and especially engineer-recruits. During the first day about 80 men of maritime engineers joint the garisson, and brought ten heavy machineguns along.
The artillery units that had been stationed at the Island of Dordrecht in the morning of the 10th had all been lost. Of the main force on the Island (with exception of the Dordrecht garrison) the majority had been captured or killed on the first and second day of the war. Only about two companies of infantry and about 200 artillery men were still at large, but of little value due to lack of officers and communication lines. Three artillery battalions positioned just left of the Kil waterway (area called Hoekse Waard) could cover the entire west side of the Island of Dordrecht with their 7,5 cm and 15 cm guns. In practise only the 7,5 cm light field artillery would really be able to expand their efforts to the Island though.
This modest Dutch force received some reinforcements from the Light Division as off the 11th. Two battalions of the 2nd (Bicycle) Infantry Regiment preceded the main task force of the division that would arrive on the 12th.
The German force present in the north of the Island in de morning of 12 May probably comprised about 1.000 men. That were about 300 men of I./FJR.1, around 200 men airlanding troops and around 500 men of III./FJR.1. Their main objective was holding the bridges at Zwijndrecht, subsidiary objective was the controlling of the city of Dordrecht and the main road leading to the south (Moerdijk).
That would change once General Student had found out that the Dutch were reinforcing their representation on the Island. His troops got increasingly challenged by several Dutch actions and so the German laid back attitude of the first two days developed into a more active and offensive approach on the 12th.
The other objective of Student's airbornes at the Island was the defence of the essential bridgehead at Moerdijk. These troops fell under the direct command of Oberst [Colonel] Bräuer, the executive officer of the 7.Fliegerdivision. The German representation near Moerdijk counted around 700 men on the 12th, of which about 500 south of the bridges. This force was mainly formed by II./FJR.1, and supported by 12./FJR.1, a platoon engineers of Pi.22, a platoon of AT guns and a half-battery of airborne howitzers of 7,5 cm. These men had to defend the bridgehead to the south against Dutch and French aggression, and to the north against Dutch counter-measures. Also, if circumstances provided for availability of forces, they were responsible to keep the main road from Moerdijk to Zwijndrecht free of Dutch occupation. Of all German bridgehead forces south of Rotterdam, one could consider the assignments of the limited force under the command of Bräuer the one with the most difficult and extensive assignment.
The Island of Dordrecht was about to face decision day this Sunday May 12, Easter Day. Overnight a considerable force from the Light Division had been shuttled across the river Merwede. A defensive screen with the strength of almost one regiment and two batteries of 7,5 cm artillery was left east of Alblasserdam in order to prevent the German air landing troops from crossing the bridge. Also a major part of the divisional auxiliary units was left behind at the Alblasserwaard [region north of Dordrecht]. This decision of leaving such a strong screen of precious troops pacified in a dead corner of the front was unnecessary, for the Germans obviously had no ambitions to cross the bridge. On their part however they grew very worried over the strong Dutch presence here [which they overrated considerably].
Lieutenant-General Student grew only mildly concerned about the Dutch formations appearing in his right fliank. His emphasize remained on the Dordrecht and Moerdijk perimeters, causing his operations staff to oppose him more than once. The General had decided that regardless of the suspected strong Dutch forces near Alblasserdam only a small force would be required to safeguard the Noord westbank east of Alblasserdam. He made sure though - by means of his direct communications with the Lufwaffe Group Putzier - that the Luftwaffe would remain on call 24/7 to assist should the Dutch presence at Alblasserdam become a burden after all. His considerations made a lot of sense, because from his point of view Dordrecht - right below Alblasserdam - was the most precarious corner of his [relatively] large bridgehead. The decision of Student paid off, double. Opposed to the Dutch plan to concentrate a regiment strong formation along the Noord, Student left only about 250 men infantry and a battery of howitzers in defence. In other words, 10% of the Dutch strength. On the other hand he had moved the III./FJR.1 battalion to Dordrecht. That was also a wise decision, countering the Dutch plan to move one regiment of the Light Division to this same area. In other words, Students measures were right on, whereas the Dutch made the fatal mistake to disperse formations rather than maintain concentrations.
The Light Division [hereinafter called LD] units that were designated to be sent to the Island of Dordrecht overnight, were scheduled to cross the river Merwede, advance to the southwest, cross the Kil waterway and as such reach the region [Island of] Hoekse Waard. From thereon they planned to march to the north again in order to cross the river Oude Maas after which an advance to Waalhaven air field would be on. This huge detour was considered (by the staff of Fortress Holland) the only remaining option for the Dutch to reach Waalhaven as an alternative to the blocked route via Alblasserdam.
It was obviously an over-ambitious plan; and not only due to the fact that the plan incorporated quite some ambitious individual milestones in itself. The projected advance across the Island of Dordrecht - where German troops were well represented - the crossing of the wide Kil - with extreme vulnerability to air strikes - and last but not least the projected crossing of the river Oude Maas where all bridges were German held. Basically the latter meant that the LD would be confronted with similar challenges as they already had faced at Alblasserdam. In stead of opting for a simple solution that fitted a poorly trained army, the Dutch went for the complex solution. A basic error.
The reason that the Fortress Holland staff considered the crossing of the Oude Maas less of a challenge than the one that they had faced previously at Alblasserdam can only be filed under the title "underestimating the enemy" (and perhaps 'overestimating the own capacity'). In fact the Dutch were well aware that both the bridges at Barendrecht and Spijkenisse/Hoogvliet were occupied by considerable enemy forces. We can only guess why their hopes to overtake these defences were so much higher than what they had been at Alblasserdam. A sensible and simple explanation is not available ...
As projected hereabove, the Dutch occupation of the Island outmatched the German presence as off the first hours of the battle. Nevertheless, the Germans had been successful in creating local superiority as a consequence of their concentrated raids and disposition. Once the bridges had been taken, they were relatively easy to defend. By mastering the basic operational strategy of moving concentrations around within the parameters of the own bridgehead, the Germans were able to control every challenge and have adequate formations within reach should the battlefield require availability of such manoeuvre formations.
The bridges at Zwijndrecht were constructed with long and elevated approach ramps, providing the defenders with a clear overview of the vicinity of their bridgehead. Surprise attacks would in fact only be feasible at night, when the huge advantages of the clear view would be diminished by darkness. Still, the harbour to the south and the railway to the east prevented assaulting forces from approaching in a stealthy covered way, from the Dordrecht side. At all circumstances the approaches to the bridge, the elevated ramps in particular, would have to be executed with force and determination, preferably with extensive artillery, mortar and MG support. Efforts like that would definitely be costly too. For the Dutch army, which lacked professional or well trained storm troopers and more particularly the moral to indure heavy casulaties, such efforts (and offers) were far from feasible. The fact that the Alblasserdam crossings had been cancelled as 'impregnable German defences' against a mere dozen KIA says it all!
The accesses of both the railway and traffic bridges at Moerdijk - which lay well apart - were hardly elevated from ground level. The land heads themselves did not provide the defender with considerable terrain advantages. The challenge to overcome here would be the rather wide stretched plains between the land heads of the bridges and the area's directly north of them. These areas were a perfectly flat polder landscape, with narrow dikes, hardly any trees and no cover against opposing air force units whatsoever. Any action against these bridges would require an assaulting force to expose itself in full, and whilst anti-aircraft artillery was totally omitted such exposure would require a lot of courage and acceptance of loss of life. Since also armoured units were unavailable, any advance had to be executed by foot or bike. Needless to say that these limited options did not sound as a pleasant invitation to Dutch field-commanders.
Gamelin had promised his Dutch counterpart [on the 10th, reassured on the 11th] that the French forces would have the strength and opportunity to re-establish the connection between the Fortress Holland and the south by defeating the German stronghold at Moerdijk. As we saw in Part I, the actual order to do so was given on the 11th and in such an ambivalent way, that the local French field command had every possibility to improvise in their advantage. Although the French commander of the 7th Army Giraud decided on the 12th that execution of the order was no longer feasible [to his perception], the Dutch headquarters were never informed of this. They therefore remained under the false impression that they could keep on focussing on the retaking of Waalhaven airfield, since the French would close the wide open backdoor. A dramatic misunderstanding and perhaps even a reproachable misjudgement. One could question whether the Dutch headquarters should have relied so much - at such an essential issue - on the French. On the other hand: did they have any realistic choice?
In the morning of the third day, the Dutch troops had a firm grip on the city of Dordrecht. Also, the entire east-side of the Hoekse Waard region - direct opposite of the Kil - was firmly occupied. The situation in the early morning of 12 May was as follows:
The Island of Dordrecht:
- The city of Dordrecht was entirely in Dutch hands. Two battalions of the Light Division were in the town itself, together with some miscellaneous smaller units and about 1,400 garisson troops. Altogether a mere 3.000 men.
- East and south of Dordrecht the remainder of III-14RA [Artillery, without guns] and little more than a company of 28RI as well as two platoons heavy machine guns and a mortar section.
The Hoekse Waard [east of the Island of Dordrecht]:
Along the entire eastside of the Island [Hoekse Waard is also surrounded by water], faced towards the Island of Dordrecht:
- a strength of about three companies from 28RI and 34RI.
- two batteries 7,5 cm field guns
- three batteries 15 cm field guns [fixed angle Moerdijk / Willemsdorp]
- a limited number of mortars, light field guns and anti-tank guns: all section-wise
The German status was - as a consequence one would say - such that the gaps in between the Dutch positions were filled with their troops. These troops concentrated around the two main bridgeheads at Zwijndrecht and Moerdijk, and the axis in between:
At Zwijndrecht/Dordrecht bridges (and quarter Krispijn):
- I./ [two companies] and III./ [two companies] battalion of the 1st Airborne Regiment
- II battalion of the 2nd Airborne Regiment [two companies plus one platoon]
- Support troops: platoon of Pi.22, half-battery 7,5 cm houwitzers and a platoon of 3,7 cm AT guns
Between Zwijndrecht and Moerdijk:
- Two platoons of 11./FJR.1 near the village of Amstelwijck
- One platoon at the hamlet of Zuidendijk
- Less than half a company (staff forces) at the Catherina Hoeve [farm on the Kil bank]
- Headquarters at Tweede Tol, incl. one platoon airbornes of the reserve company
- North and south of the bridges the entire II.Battalion of 1st Airborne Regiment, reinforced with a platoon of AT guns, a half-battery 7,5 cm howitzers and half a platoon of pioneers of the airlanding troops as well as 12./FJR.1.
If one would look on the map of the region it becomes clear that the entire axis between the Zwijndrecht and the Moerdijk bridges was controlled by the Germans. They had built a rather strong screen along the west and south-western city-borders of Dordrecht, at the highway leading to Moerdijk, and the Moerdijk bridgehead itself. The troops at the Zwijndrecht bridgehead had been reinforced to a force of about 1.500 men with a number of 7,5 cm Skoda mountain-guns [range 11.000 metre]. Their central forces contained no more than a few hundred men. The occupation of Amstelwijck was of importance. It not only meant the control over the highway, but also it could control any shore landing on the Island form the Hoekse Waard. For the same reason some troops had been deployed around the Catharina Hoeve [farm house] and at Willemsdorp [close to Moerdijk]. The strength at the Moerdijk area had remained the same. Some reinforcements had been received, but the force would at no point exceed the number of 600-700 men.