Liverpool, Albert Dock. Refit for HMS Wallflower (K44)

3 May 1942. Abbekerk is still waiting for orders to leave Colombo. Meanwhile in England the corvette HMS Wallflower is getting a big overhaul after two years of intense convoy service. Her equipment is also modernised and that will prove to be a lifesaver for the Abbekerk crew four months down the line. A good reason to take a closer look at this vessel and its history.

The principal of Asdic: soundwaves reflecting on a submarine

In the years leading up to WWII England put great faith in Asdic, the predecessor of Sonar. These systems locate, through sound waves, submerged submarines so that they can be destroyed with depth charges. The faith in Asdic was so great that a substantial fleet of escort vessels was deemed unnecessary. Soon after the outbreak of the war it proved less than a cure-all. The U-boats attacked mostly at night on the surface and there Asdic couldn’t see them. And so England was forced to – just as in WWI- introduce a convoy system to protect the merchant  ships and secure the supply of England. They were now faced with a shortage of vessels to protect the convoys and fight submarines.

The (short term) solution: The Flower Class corvettes. A small warship of simple design and based on proven techniques. They could be built quickly at small shipyards all along the coast and be manned and sailed by crews without very specialized training. In 1942 the Flower Class corvette, manned by Royal Navy Reserves (RNR) and often under the command of a merchant navy captain, is the backbone of the convoy escorts in the Atlantic. The small vessels are named after flowers: Violet, Snowberry, Bittersweet- and in K44’s case HMS Wallflower.

Corvettes were small en very uncomfortable in the rough North Atlantic. HMS Bittersweet (K138)
(Source: Pinterest)

Rugged and seaworthy as they are the corvette is designed for short patrols along the coast and they proved to be highly uncomfortable for the crew during the long journeys on the cold and rough Atlantic. Besides that, they are just lightly armed with one 4 inch canon and one anti-aircraft gun. But with 70 depth charges on board she is extremely dangerous for submarines. She is powered by a classic ‘triple expansion’ steam engine which gives her a maximum speed, on Calm waters, of just 15 knots. Enough to keep up with the slower convoys, but not enough to chase submarines and rejoin the convoy later. And – not unimportant – slower than a submarine sailing on the surface.
In few years time 150 were built and 20 were sunk by torpedo’s or mines.

Back to the Wallflower which escorted more than 22 convoys during the last year. To a.o. Halifax (Canada), New York, Freetown, Gibraltar en Tokoradi (Ghana). She’s in the dock for months for maintenance and modernisations. As one of the first corvettes she is fitted with Radar. As Asdic uses sound waves in the water, Radar uses radio waves through the air. If the waves hit an object they reflect back and distance and direction can be measured.

HMCS Bittersweet (K182) . Note the radar dome (‘lantern’) on the bridge just before the funnel.

England has a massive advantage over Germany with their Radar development. Germany thinks it’s impossible to build small enough Radar units to fit onto small vessels, let alone that the would be effective against a small target like a submarine. Nothing could be further from the truth. The English even develop a Radar to fit within a plane. This miscalculation will prove to be one of the biggest contributing factors to Germany finally losing the battle of the Atlantic in the end.

Corvette and Submarine page 78

Corvette and Submarine page 77

Wallflower is fitted with the Type 271 centimetric Radar, the first type which, under the right circumstances, could even detect something as small as a periscope. In the dark and in the mist and from a much larger distance than the human eye could ever do.
Next, two pages from the book Corvette and Submarine written by Max Sheen in which he is getting acquainted for the first time with Radar on the HMS Bluebell. ( thanks to Roy Terry, who’s father served on the Wallflower).

As Wallflower leaves port mid July to connect with convoy ON128 it is a nearly new ship and under the command of Lt. George Richard Greaves, RNR

Wallflower escorted 22 convoys between April 1941 and March 1942

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