How did minesweepers operate in WW1

Hello all,

I've learned, from this forum, about minesweepers (paddle steamers, fishing boats, etc.) in WW1 but not on how they actually dealt with the mines.

I'd appreciate if someone could tell me how such an operation was carried out. Is there a good book, I can read? Is there a good website that tells me how?

I'd be grateful for any help.

Thanks Naval_Gazer.

I've seen, what I think were, the relevant pages from "Swept Channels" and, together with everything else I've read - extracts from other books, website forums (this one mainly), and including a newspaper article on minesweeping, dated April 1915 - I felt I could do with a good, easy to understand, simple explanation. I've read about paravanes and cutting the wires/chains that held the mines below sea level but can't understand how the paravane actually did the cutting. Did one ship tow one paravane or two (as one article seemed to suggest) or did two ships work together on one mine, as another seemed to say?

To be honest, Naval-Gazer, I didn't want to spend any more money on a yet another book that I might never refer to again - I'm always doing that! The other website you mention looks interesting from many points of view.

Thank you for your reply and I hope you don't think I'm too mean to buy the book but, in these times, as a pensioner (there go those damn violins again!) I have to curb my enthusiasm for buying books a bit - plus, I'm not just running out of shelf space but anywhere to put more shelves!

Thanks again - I might just persuade my wife that I really do need this book - then, again, I may fail!
Hi Seaweed,

I had come across this website and it's the one that shows two boats/ships working together while other books/websites talk about one ship/boat. It's also using a steel "bight" and a see-sawing action, while others talk about using a paravane. It's very interesting and thanks for telling me!

I can understand the two ship method though I'd love to know how a steel "bight" (whatever that is) could cut through what looks like a very strong and very heavy steel chain, even with a see-sawing action - and that sounds like a very difficult and dangerous operation to me. Similarly, though, how on earth could a paravane do it? I really need to do more reading!

Thanks again, Seaweed, one day all will become clear (I hope!).
Hi again, Seaweed,

Looking at the manual (and there's a lot more there to read than I thought, so thanks again) the "kite" mentioned is, obviously, what others call a "paravane". Several books/magazines/websites (I forget which, now) talk about one boat being used so I'll have to see how that might be possible.

Johnny - Early mine sweeps simply comprised chains towed over the seabed between two ships or even by a single ship to drag mines and their moorings out of a channel. These were later replaced with serrated wire cables towed between two ships (Actaeon Sweep). Development of the Oropesa Sweep with its divertors and depth-keeping kite allowed sweeps to be towed by a single ship. Sweep wires were made from flexible steel wire rope and streamed from each quarter of a minesweeper. The cables were laid right or left-handed according to the side streamed. This helped the wires achieve hydrodynamic lift and spread. A single strand in each wire was laid in the opposite direction to provide a serrated cutting effect.

Moored mines only had a short length of chain shackled to them. The rest of the mooring was wire cable or even sisal rope in some cases; otherwise the mine would have been unable to support the weight of its mooring particularly in deep water. This was the part of the mooring that the sweep wire or any fitted cutter was intended to sever.

Burney explosive paravanes were deployed from torpedo boat destroyers in a configuration known as the 'High Speed Sweep' to counter submarines. However, most paravanes were non-explosive and were streamed by larger warships and merchant ships as self-defence measures to divert moored mines away from their hulls. They comprised a wire streamed to each side from the bows with a float secured to the end to divert it outwards. See paravane.

From the MCDOA website:


At the beginning of WW I, British regular minesweeping forces comprised 10 ex-torpedo gunboats fitted with the Actaeon or 'A' sweep in 1908/95. These were HM Ships Speedy, Circe, Hebe, Jason and Leda of the Alarm Class and HM Ships Gossamer, Seagull, Skipjack, Spanker and Speedwell of the Sharpshooter Class (called the Gossamer Type after conversion). HMS Circe had been built in 1892. The first British mining casualty occurred on the second day of the war when the new British 3,500 ton light cruiser HMS Amphion was sunk by a mine laid in the Thames Estuary by the German auxiliary minelayer Konigin Luise...

By 8 August 1914, 94 fishing trawlers had been mobilised and converted for minesweeping. By 22 Aug, a further 100 trawlers had been commandeered and fitted out. By the end of the war, British minesweeping forces comprised 726 vessels including 110 regular naval vessels (mostly Acacia Class, Azalea Class, Arabis Class, Hunt Class and Aberdare Class Fleet Sweeping Sloops), 412 trawlers, 142 drifters, 52 hired paddle steamers and 10 Dance Class 'Tunnel Tug' shallow draught minesweepers. 214 British minesweepers had been lost in action while sweeping over 30,000 mines.

Early British minesweeping was limited to the towing of a ground chain from two spars set across the stern of a vessel but this resulted in an extremely narrow swept path and the chain was easily snagged by seabed obstructions. The next development was a serrated wire sweep towed between two ships. Otter boards, used by fishermen to keep open the mouths of their nets, were employed to increase the width of the bight of wire in contact with the seabed. This simple design frequently became snagged on rocks and wrecks on the seabed but technicians based at HMS Vernon overcame this problem with the introduction of redesigned otter boards known as kite otters. These were not only used to divert the ends of the sweep laterally but others could be rotated 90 degrees and used to depress the ships' ends of the sweep wire to a chosen depth. This was the basis for the British Type Actaeon or 'A' sweep used for almost all Royal Navy minesweeping operations during WW I. It was effective for depths down to 50 fathoms.

Later in the war, technicians at HMS Vernon developed an improved technique that could be used by one ship alone. This led to the Fleet accepted design in 1919 of a single ship wire mine sweep named the Oropesa Mk 1 after the Fleet minesweeping trawler involved in the trials. This system avoided the need for ships to operate in pairs. The Oropesa sweep was held at the correct depth by a kite otter and taken out on the quarter of the sweeping vessel by another kite on its side or by an otter board supported by a float. A 'V' cutter was secured to the end of the sweep wire to sever the mooring cable of any mines that had not already been cut by the serrated sweep wire.

In 1914 trials were proposed for a new type of bow protection gear to be fitted to British merchant ships operating in the North Sea. This comprised four heavy spars heeled against a chain passed around the forefoot and stayed from the forecastle with a net spread between the four forward ends of the spars. However, it was subsequently decided that there was no requirement for bow protection against mines so no trial was conducted. A demand then arose for bow protection for battleships as well as improvements in the gear provided for trawlers and torpedo gunboats. It was decided to fit such protection to as many minesweeping vessels as possible and to test any promising gear. Trials of similar systems were conducted between Oct 1914 and Dec 1916. These included:

Wilson Gear.
Ollis Gear.
Exmouth Gear.
'Campania' Gear (Director Naval Construction Type).
SCW Gear (Superintendent of Contracts).
Skipjack Gear.
'Raglan Castle' Gear.​

In view of the potent German mining threat in the North Sea, Admiral Jellicoe called for minesweepers to proceed ahead of the Grand Fleet but he soon realised this would severely reduce the Fleet's speed of advance. He therefore urged the introduction of a minesweeping device that could be fitted to Fleet units themselves. Commander Cecil V Usborne RN of the battleship HMS Colossus proposed trials of an apparatus that could deflect any mine not encountered head on. It comprised two sweep wires, each fitted with a 'hydro-vane'. This was originally conceived by Lt Dennis Burney RN of the destroyer HMS Velox to deflect an experimental anti-submarine device clear of the ship towing it. When 'hydro-vanes' were secured to the ends of two sweep wires, they diverted the tail ends out from each side of the ship. Ultimately, this minesweeping device became known as the 'Paravane' and was fitted to the bow of all larger Royal Navy ships and many merchant vessels.


In September 1914 the Turkish commander responsible for the defence of the Dardanelles closed the narrow strait with minefields. In August 1915 Vice Admiral Guido von Usedom (a German officer assigned to the Turkish as 'Inspector General of Coastal Fortifications and Minefields'), was sent to inspect the defences. Von Usedom expanded the Turkish mining effort and created a defensive minefield of over 300 German 'Carbonit' moored contact mines in eleven lines protected by the fixed guns and searchlights of forts and 74 mobile artillery pieces.

In December 1914 the British approved an operation to open the Dardanelles using naval forces. They used 21 former North Sea trawlers converted into minesweepers and manned by civilian fishermen. These operated in pairs about 500 yards apart sweeping with a single 2.5 inch wire and a one-ton twelve foot long kite to keep the wire at depth. British minesweeping was ineffective on the first eight nights owing to strong currents and enemy fire; the trawlers repeatedly withdrew under harassing fire from enemy gun batteries and one was mined on 10 March. This led to a daylight operation which again saw the converted minesweepers withdraw under fire. On 18 March 1915, a major Fleet attack was attempted in order to silence the Turkish coastal guns. The minefields caused the loss of the British pre-dreadnoughts HMS Irresistible and HMS Ocean and the French pre-dreadnought Bouvet and inflicted severe damage on the battle-cruiser HMS Inflexible. Two more British capital ships were lost from gun fire. The British thought the mine losses were due to floating mines but the losses were actually caused by a new and undetected line of moored mines laid by the small Turkish steamer Nusret on the night of 7/8 March.
Hi Naval_Gazer,

That's brilliant! That explains, in simple terms, all I wanted to know. I'd read about the cables and how they were laid in opposite directions, and kites, and paravanes but the problem seems to me that the books/ magazines were, possibly, talking about different times in the development of minesweeping.

No matter, I've read what you've said and I'm happy! I shall read it again many times, I'm sure, before I fully understand but that's fine.

Thanks to all who have helped me - I'm very grateful.

'How did Minesweepers operate'? Carefully I would have said..:rofl:On a serious note, there was a book I recall, I think it was called 'Outsweeps' It was very good, with some good dits. Think it may have been about WW2 Minesweepers though.
Hi Sarking,

Just to show I, too, have a sense of humour (not much sense and not a lot of humour, actually) I thought that "Carefully" was a Welsh Cheese, but there you go! The book "Outsweep" seems to be about WW2 but thanks for your input - and your joke!


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