On the 1st of October 1935 the Koninklijke Marine appointed Schagen van Leeuwen to assistant of the direction NV Hazemeijer Signaal-Apparaten. Before the outbreak of the war he had asked to not cut off his telephone line, but on that fateful morning the demolition parties had done so anyway. After cycling to the police station he came in contact with the colonel. The colonel had ordered his troops behind the IJssellinie. “In 10 minutes the Germans are at you. I cannot help you further. Be well.”
Schagen van Leeuwen hastened to the train station to potentially prepare a train with important materials and devices. However, all trains had already departed. Soon after motorised troops arrived and occupied the station and soon after an armoured train joined them. Arriving back home he had found his own staff, amongst them H.C. Ackermann, Engineer Buitenhuis, Kuyvenhoven and a number of army NCOs. It was decided to head west with the greatest haste and thus the party embarked on their bicycles in the early morning.
The original plan was to traverse the IJssel at Zwolle, but after circumstantial observations they directed to Zwartsluis. After seeing Zwartsluis occupied they moved further and late in the evening arrived at Vollenhove. With the help of the mayor a boat was arranged to direct them to Hardewijk. After arriving in the early morning Hardewijk was deserted from all transport and after some bicker transport to Edam was arranged.
After taking some various detours in Amsterdam, Haarlem and den Haag the group arrived on the evening of 13th of May at den Helder in order to secure passage to England and continue the war effort. Aside from the Hazemeijer quadruplet they were joined by v. Adrichem Boogaert, van Haaften, Pröpper, O. de Booy et al. At den Helder H. Jolles welcomed the group from den Haag, but had the unfortunate news that no transport was available. The group was joined by a few more officers, amongst them Houtsmuller and Harmsen. De Booy remembered that de Rijkswerf had a fast open torpedo chase boat.
The crew departed after midnight along with 6 ton of material. S. A. l’Honoré Naber was in charge of fort Harsens and under orders to fire at any unannounced arrivals or departures. But fortunately after hearing about an escaping torpedo chaser he deviated from assignment and did not give orders to fire. At daybreak the crew was picked up by a British Coast Guard trawler and arrived safely in Great Yarmouth.
After a demonstration by Willem van der Zaan and her 40 mm AA battery Vickers-Armstrong was tasked to deliver 200 complete assemblies as soon as possible. With the establishment of the Koninklijke Marine headquarters in London a task was sent to Marine Etablissement Soerabaja to deliver copies of the 40 mm blueprint microfilms. Schagen van Leeuwen was closely involved with this project. He had advised against making complete copies, as there were a number of teething issues. The British refused any of the suggested changes, which would naturally give them complications later on. However, a single change was implemented. Namely the replacement of the stereoscopic rangefinder with a radar-set.[note 1]
Naval Ordnance in Bath and Naval Research in Teddington were annoyed that Vickers was tasked with a project neither from their or Vickers’ origin. Resistance against the 200 assemblies was inhibitory and thus through Naval Ordnance a request was put forward for tandem projects. Kuyvenhoven was tasked with some assistance of Schagen van Leeuwen to help the Vickers Armstrong design bureau develop the “Buster”.
Meanwhile, Naval Ordnance started their own project for “Staag” to outshine the “Buster”. When the design was finished they started a demonstration in Portsmouth in front of hundreds of authorities and experts. Results were unanimously disappointing. A draughtsman from Bath told Schagen van Leeuwen “It seems the safests place for an aircraft is in the air, sir!” In a debriefing Schagen van Leeuwen called it the worst AA gun he had seen.
The “Buster” embodying the Dutch and Schagen van Leeuwen’s ideas did find success under Kuyvenhoven and the mock-up received approval from the British Royal Navy. Two proto types were ordered from the Vickers-Armstrong factory at Dagenham. However, the bickering of Department of Naval Ordnance and the Admiralty Research has triumphed and the “Buster” was shelved.[note 2]
During the brief moment Kuyvenhoven was free from Teddington and Dagenheim, he and Ackerman searched tirelessly in patent offices through German files for an improvement in the stabilisation of the top. A solution was found in a mercury switch and after tireless work the assembly was made completely independent of the gyro compass.
It was not just the British Royal Navy that received the 40 mm Bofors from the Netherlands. J.E. Meyer Ranneft received word from Captain Blandy that the Americans had trouble with their 2.1-inch gun. Blandy wanted to see it in action and arrived at Trinidad where on the 20th of August the Tusacola and van Kinsbergen demonstrated the gun. Meyer Ranneft managed to get a complete set of micro films for the United States.
Meanwhile, Weiler, Kuyvenhoven, Staal and Houtsmuller worked tirelessly on the Isaac Sweers. Creating what was known as the RDF 289 with ca. 22 km range. Staal had also developed radar jammers.
After these endeavours Staal travelled to Ceylon to install various air warning radars. Followed by installing IFF devices on Marine Luchtvaartdienst aircraft, as well as American search radars. However, those were not supplied with aerials so Staal designed and developed them on-site himself.
Furthermore, he installed radars on the Hr Ms Soemba and Hr Ms Willem van der Zaan. This proved arduous as the Soemba was equipped with Dutch Hazmeijer fire control and a method of conversion from yards to metres had to be made, which was helped by a Swiss watchmaker in Bombay.
In 1944 the Hr Ms Tromp was to be refitted in Sydney with modern radar material shipped from the United States. However, no generators were supplied and the Americans worked with 60 Hz Alternating Current whereas the Dutch worked with 50 Hz. A solution was found by using the old Direct Voltage generators from the searchlights and using a converter made by Australian General Electric Company. The company was scared of this idea, but the Australian technicians were duly impressed by the Hazemeijer switches and the system had worked splendidly throughout the war.
Whilst Staal was on his grand tour in the east, von Weiler et al. were joined by D. Smit, G.D.A. van Beek and Boddaert as well as later Engineer J.H. Wiersum, P.D.Kruyt and Engineer Slikkerveer. The whole department was moved from Portsmouth to Witney in July to form the Admiralty Signal Establishment. Whilst the British were mostly occupied with search radars, the Dutch specialised in artillery radar. Here the group of von Weiler did a lot of work, but particularly they designed the 50cm radar with T/R switches, their antennae, radar linkage and synchronisation, moving target indication and anti-jamming devices. He had also worked on solving the issues of the 3cm radar which allowed the Canadian production to commence.
[note 1]: it seems originally the RDF type 262 was conceived to be used but this was too heavy. (Friedman, N., Naval Anti Aircraft Guns & Gunnery chapter 8 note 49.) It was further hoped to create the CRS 1 (Close Range System) director. This project was cancelled and instead development from the STAAG was repurposed into the CRBFD (Close Range Blind Fire Director) (Friedman, N., Naval Anti Aircraft Guns & Gunnery chapter 8 sub Fire Control)
[note 2]: of 102 assemblies ordered, only one system was delivered in the last quarter of 1947. (Moore, G., The ‘Weapon’ and Gallant Class Destroyers, Warship 2000-2001.
Sources:
Bezemer, K.W.L., Verdreven doch niet verslagen
Staal, M., Hoe de radar naar Hengelo Kwam
Ir. Kasper, R.A., Professor von Weiler, oprichter van het Laboratorium voor Elektronische Ontwikkelingen, LEOK Jubileumboek 1975
NIMH 092 Marinemonografie, 2.8 De bewegingen en akties van Hr.Ms. Isaac Sweers. Appendix 1: Bijdrage van de Koninklijke Marine in de technische vervolmaking van de geallieerde scheepsartillerie en vuurleiding - compiled by Ackerman June 1956 - and Appendix 2: Ervaringen in Engeland tijdens de laatste wereldoorlog van een groep radarspecialisten.
Images:
NIMH Collection 2158_014041
Tyne and Wear Archives DS.VA /6/PL/140 - BUSTER mounting
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