K-class sloops

The K 1, K 2 and K 3 were laid down as part of the 1938 naval estimates to replace the obsolete Gruno-class gunboats. Their armor and heavy anti-aircraft armament would have made them suitable for local defence of shores and ports, and use as anti-submarine and anti-aircraft escort. Four more were planned under the 1939 estimates, of which only K 4 and K 5 had been ordered. On May 10, 1940, the first three had not yet been launched and were found undamaged on the slips by the German occupying forces several days later. The orders for K 4 and K 5 were canceled by the Dutch Naval Staff.

The German Kriegsmarine ordered the completion of the first three ships. Minerails were added, whereas the planned main armament of high angle/low angle anti-aircraft guns were replaced by low-angle turrets. During the war, these ships gave good service in Norwegian and German home waters. After the war, only K 3 was repaired and put into Dutch service.

K 3 as completed (collection webmaster)

Construction Details

Name K 1 K 2 K 3 K 4-5
Dockyard P. Smit Jr, Rotterdam Gusto N.V., Schiedam P. Smit Jr, Rotterdam P. Smit Jr, Rotterdam
Laid down August 2, 1939 1939 June 23, 1939 -
Launched November 23, 1940 June 28, 1941 March 22, 1941 -
Completed October 2, 1941 * November 14, 1942 ** February 2, 1942 ***
July 18, 1946 in RNN
Pennants K 1 K 2 K 3
N-5 (from June, 1946)
F-805 (from 1953)
* Marine Rundschau mentions commissioning as September 28, 1941 (Marine Rundschau)
** Date of commissioning is also listed as October 23, 1942. Based on K-2's war diary, I've decided on November 14, 1942.
*** Date of commissioning is also listed as February 1, 1942 (Van Amstel, Mark)


Design Kriegsmarine
Displacement 1267 tons
1470 tons (full load)
1200 tons
1420 tons
Crew 99 161-184
Dimensions 77,90 x 10,30 x 3,40 m
Armament* 4 x 120 mm Bofors (HA/LA) (2x2)
4 x 40 mm Bofors (2x2)
4 x .50 MG
4 x 120 mm Bofors No. 8 (LA) (2x2)
4 x 37 mm (2x2)
12 x 20 mm (2x4, 2x2)
Mines - ca. 80**
ASW 12 depthcharges 8 depthcharge throwers
Fire control system*** N/A N/A
Radar N/A N/A
Asdic N/A N/A
* These ships also carried sweepinggear against contact- and acoustic mines
** I have also found 200 mines (presumably from Erich Gröner "Schiffe der Deutsche Kriegsmarine und Luftwaffe 1939-1945 und ihr Verbleib")
** There are indications the fire control system was manufactured by Philips in Venlo. I have never heard of this company producing this equipment. More information is appreciated.


Deck 20 - 35 mm
Belt 37 - 60 mm
Turrets 60 mm
Conning tower N/A
Fire control position N/A
* Armour data is (presumably) from Erich Gröner "Schiffe der Deutsche Kriegsmarine und Luftwaffe 1939-1945 und ihr Verbleib"

Propulsion details

Design Kriegsmarine
Machinery Burmeister & Wain diesel engines* 2 Klöckner - Humboldt - Deutz 6-cylinder 4-stroke diesel engines*
Performance 3500 hp 2770 hp (K 1/K 2)
3500 hp (K 3)
Shafts 2 2
Range   6900 nm @ 12 knots
Bunkerage   157 tons oil
Max speed 19 knots 14,5 knots (K 1/K 2)
18 knots (K 3)
* Built under license by P. Smit Jr. in Rotterdam
** K 1 and K 2 apparently had their original powerplant replaced by these submarine-engines in 1943 at Howaldtswerken, Kiel (Marine Rundschau)


K 1 Damaged in Flekkefjord (Norway) by air attack. Sunk near Aarhus (Denmark) by rockets from RAF Mosquitoes on May 5, 1945
K 2 Hit in the stern by aerial torpedo October 9, 1944 off Egersund (Norway) while escorting convoy KS-328-T. Towed to Egersund by the minesweeper M-1, and found in Horten in 1945. Towed to Delfzijl, where the ship accidentally sank in November, 1945. Raised July 26, 1946 and towed to Den Helder for inspection. Finally sold for scrap in October, 1947.
K 3 Found in Horten (Norway) in 1945. Repaired at the Rijkswerf in Amsterdam and commissioned in 1946 as Van Speyk. Re-engined with Sulzer diesels from the submarine O 23 in 1953. Stricken June 14, 1960. Sold for scrap August 29, 1960 to W. Mantel, Amsterdam

Sources and related links

A.J. Vermeulen "De schepen van de Koninklijke Marine en die der gouvernementsmarine 1814-1962 (1962), pp. 134-135
W.H.E. van Amstel "De schepen van de Koninklijke Marine vanaf 1945 (1991), pp. 27
Chr. Mark "Schepen van de Koninklijke Marine in W.O. II" (1997), pp. 54
E. de Jong "Versenkt, wenige stunden vor dem Waffenstillstand (Kanonenboot K 1), Marine Rundschau 5, May 1983

Related links (please report any broken links)
German Naval History - page for K 1
German Naval History - page for K 2
German Naval History - page for K 3
Dreadnoughtproject.org - large scale plan of K 3 as completed
Dreadnoughtproject.org - large scale plan of the original Dutch design

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