Thread by @cocteautriplets

On our trip to Orkney we visited the excellent and newly refurbished Scapa Flow museum, and I bought a book on the subject of the internment, scuttling and salvage of the German Hochseeflotte after WW1. So naturally I've managed to find an exciting local history angle to this🧵👇

So tonight's thread is entitled "The last voyage of the Battlecruiser "Moltke". Or how a German Warship almost destroyed the Forth Bridge almost 10 years after the end of the war"

The "Moltke" was a 25,000 tonne battlecruiser of the Imperial German Navy, 612 feet long, 96.5 feet wide, she could make 25.5 knots on 51,000 horsepower and was armed with 10 x 11 inch guns in 5 turrets. She was more than an equal to her Royal Navy equivalents.

At the end of the war, the German fleet (Hocheseeflotte) was still largely intact and was forced by the Allies into a humiliating internment in the bleak confines of Scapa Flow, under the watchful eye of the Royal Navy. Moltke is 2nd in line in the picture. (📷NHHC NH59665)

As the signing of the Treaty of Versailles approached, the German Admiral in charge at Scapa, Von Reuter - in an impossible position between national honour, British belligerence and Allied pressure - managed to scuttle nearly the entire fleet under the nose of the Royal Navy.

He had actually probably done everyone a favour and simplified negotiations over its fate - If the German Navy lay at the bottom of Scapa Flow then nobody could have it. Not the British, the Germans, the French or even the Italians who somehow felt they deserved a portion.

The German wrecks were something of a navigation hazard - as demonstrated ably by the whaler "Ramna" stuck fast on top of the capsized hull of the "Moltke", but they were soon quietly forgotten about, and the world moved on.

Enterprising locals (often unofficially) salvaged what they could access above water, until an enterprising Shetland councillor - J. W. Roberston - proved that you could salvage wrecks from underwater and brought a number of torpedo boats ashore for their scrap value.

Enter stage left the enterprising, irrepressible and energetic figure of Ernest F. Cox. Cox was a self made engineer and metal dealer from the Midlands who had the vision to believe he could access and salvage the near half million tons of German steel at the bottom of Scapa Flow

Cox had the foresight to hire Tom McKenzie, a Glaswegian naval salvage diver who would pretty much write the book on naval salvage diving.

Cox's company - Cox & Danks (Danks was his cousin, a silent partner and the capital behind the operation) - bought the rights to salvage the Hocheseeflotte from the Admiralty and set to work at Scapa in the mid 1920s.

Although everyone involved were practical, skilled and experienced men, they were starting from almost nothing and basically had to invent all the techniques, improvising and making things up as they went. Overcoming setback, driven by Cox's determination and Danks' deep pockets.

Cox made rapid progress and his first torpedo boat - V70 - was raised after less than 2 months work in 1924. Moving on, they honed the techniques and were soon raising ships at a rapid rate. Within 2 years all 26 torpedo boats he had the rights to were raised.

Cox now turned his attention to the big ships of the fleet, the Battleships and Battlecruisers. In May 1926 they started on the "Hindenburg", but the operation was a disaster and she had to be resunk. Things were saved by the discovery of huge stocks of coal in the "Seydlitz"

Access to the free fuel from the Seydlitz tided the operations over and Cox now set his sights on the "Moltke". The technique was *relatively* simple. You plugged the holes in the hull and pumped in compressed air. You plugged any more holes, and eventually it would float.

I say relatively - it was tremendously difficult, and at the limits of diving skills and technology at the time. Conditions were harsh and the environment of Scapa Flow was unforgiving. But Cox' determination and McKenzie's skill drove them forwards.

The Germans had wrecked the watertight integrity of the inner bulkheads of the ships, so before they could be raised in a controlled manner, divers had to go in and restore it by welding and plugging any gaps they could find.

To make this possible, airlocks - like huge submarine chimneys - were built down into each compartment. From these divers could access the innards and get to work under intense air pressure, working upside down on ships encased in marine slime, often in complete darkness.

Cox was a bit of a showman, and was always on site, always hands on. The men respected him and the press loved him. The Scotsman filed almost weekly progress reports on the salvage of the Moltke.

📰October 21, 1926. Compressed air pumping operations commence on the hull of the Moltke.
📰 December 10, 1926. Moltke is rising unevenly and the divers are forced to sink her incase she is caught by the winter gales.

📰Feb. 15, 1927. Work restarts after winter storms, the first airlock is fitted and almost 100 men are at work on the Moltke.
📰 Feb. 24, 1927. The difficulties are described of working in a 15PSI atmosphere where cutting torches burn up the oxygen as fast as it can be pumped in

📰May 30, 1927. Work resumes again after 2 months of gales. A disaster is narrowly avoided when the wrong valve is closed and compressed air rushes through the ship from stern to bow, blowing the 16 divers at work inside through the ship with it.

🎥June 13, 1927. Cox has the Pathé newsreel men on site to witness the triumph of the Moltke breaching the surface in a controlled manner and refloating after 8 years on the seabed. (you can watch the whole clip here britishpathe.com/video/british-…)

Over the next 4 months, the refloated Moltke is painstakingly winched towards Cox & Danks' salvage base at Lyness on the island of Hoy, narrowly avoiding grounding on the island of Cava when one of here 11 inch guns fouls the seabed and has to be cut free.

Cox & Danks begin cutting the Moltke up, but it soon becomes obvious that the shores of Scapa Flow are the wrong place to do this, and it makes no economic sense. Cox agrees to lease the No. 3 Dry Dock at Rosyth from the Admiralty, the largest and most modern in Scotland.

Cox also sells the salvage rights on to the Alloa Shipbreaking Company, who will undertake the actual scrapping work at Rosyth and leave him to concentrate on the dark arts of salvage. But the problem is how to get the upside-down hulk of Moltke 250 miles south to Rosyth.

The only solution is to refloat it and tow it there - a hard enough task if it didn't include having to transit the Pentland Firth, which has infamous tidal currents, some of the fastest in the world.

Undaunted, Cox sets to work. The Moltke is lightened of thousands of tons of steel such as propellors, shafts, armour plate etc. and patched up with concrete where they had started to demolish the hull, and is refloated.

For the journey, two shelters are built on board, one with bunking and a galley for the 8 crew who will make the journey (including Cox himself), the other with enough pumps to keep her full of compressed air. Lifeboats are thoughtfully included too.

By May 18th, Moltke is ready to go. Controversially (at the time, both in Britain and in Germany), the 3 tugs who will take her on her last voyage are German, from Hamburg, including the "Seefalke" - the most powerful in the world - and the "Simsun"

For good measure, on board is William Mowat, the coxswain of the Longhope Lifeboat, to pilot the wallowing hulk out of Scapa and past Duncansby Head. "Bill" Mowat is middle row, 2nd from left. (📷 Orkney Image Library, 10060 )

Despite Mowat's presence as pilot, disaster almost strikes when the weather gets up. The 3 tugs cannot make headway against the wind and current and Moltke starts going backwards though the Pentland Firth, and rolling up to 13.5 degrees.

She loses 6 feet of precious draught as the compressed air bubbles keeping her afloat are lost through the rocking motion, beyond what the pumps can keep up with. Fortunately the turning tides come to her rescue and she is ejected out of the Firth by the changing current

After this rocky (literally) start, things calm down and the pumps are able to refill the air bubbles and she begins to rise out of the sea again and the tug can make headway.

Indeed the close call is soon forgotten about, and Cox the showman has the crew play a makeshift game of cricket on the deck for the press. I think he is umpiring at the back, in the pullover with his hands behind his back. (📷@OrkneyLibrary)

The rest of the journey to the Firth of Forth proceeds calmly and according to plan, and by May 21st she is off Granton. The last manoeuvre required of the tugs is to get her safely under the Forth Bridge and into the Rosyth basin.

And this is where things start to go wrong. Again. And this time it's down to petty officialdom. The Forth Pilot arrives from Granton and tries to take command of operations. He is joined shortly afterwards by the Admiralty pilot from Rosyth.

The two now get down to a jurisdictional argument worthy of a Hollywood cop movie over who has the rights to pilot the Moltke down the Firth. Neither is willing to back down and the set to keeps on going. All the time, the currents of the Firth are gradually easing Moltke west

Before they know it, they are upon Inchgarvie island, the rock on the Firth on which a pier of the bridge is built. And the newsmen from Pathé are there to film it all! One of tug grounds on Inchgarvie...

The "Seefalke", attached to a line at the back and in charge of providing steerage for the hulk of Moltke has drifted around the other side of the island and has to cut the tow. Moltke is now at the mercy of the currents, with 2 tugs lashed to her who cannot steer her.

Moltke, out of control, turns through 90 degrees and now drifts sideways down the Firth towards the bridge, dragging the helpless tugs with her. She is heading straight towards the central pier, all 23,000 tons or so of her.

youtube.com/clip/UgkxaYqA4… If you watch the remarkable clip, you can see her drifting beam-on towards the bridge, as a train goes by overhead.

Somebody must have been saying their prayers, as somehow the two tugs lashed to Moltke's hull somehow manage to position the 612 feet wide, floating wrecking ball perfectly between the piers of the bridge and avoid disaster

The Seefalke is able to get a line across and they bring Moltke under control and steer her towards the safety of Rosyth. The watching press were blissfully unaware how close disaster was, the Scotsman reports "a wonderful piece of navigation and most successfully performed"

Moltke is edged towards No. 3 Dry Dock, and Cox is about to breathe a sigh of relief. He just has to get her into the dock, as he won't get paid by the Alloa Shipbreaking Co. until she is in and the dock is drained.

This is no small feat - there is a 1 day window on the highest spring tide to get the upside down hulk in (ships usually go in the right way up, of course!). Moltke is drwaing 41 feet of water at her deepest, and there is a lip on the dock of only 38 feet...

Cox is undaunted - by an incredibly skilful act of pumping compressed air in at one end and letting it out at another, and then repeating it in reverse, they are able to "hop" the deepest part of the superstructure over the lip and get her safely into the dock and the gate shut

And then, just as he is about to triumph, once again the Admiralty almost screw everything up for Cox. With Moltke sitting in the still flooded dock, the supervisor steps in and starts an argument about how to support the upside down ship on the dock floor.

The supervisor has a point - ships normally go into a dock the right way up, and settle on their keel. Moltke is upside down and there are all sorts of projections underneath. The supervisor is there to look after the dock and can't see it being damaged.

But the Admiralty should have worked this all out with Cox before they signed over the use of the dock to him. Frantic calls are placed to Whitehall, and Cox jumps straight on the train and heads to London to thrash it out.

An agreement is made about how to support the hull, and Cox is back the next day, the 28th May, and his men get to work shoring it up with baulks of timber. Then the dock can slowly be drained and the ship can come to rest on them.

On June 5th the last of the water is pumped out and Cox has finally triumphed. He has raised a 23,000t ship from the seabed after 8yrs (twice!), beached it, refloated it, sailed it 250 miles through the treacherous Pentland Firth and squeezed it upside down into a dry dock 🥳

The Alloa men can now get to work and on September 13th 1928 set about cutting up the pride of the Hocheseeflotte into thousands of tons of scrap metal.

Cox would go on to salvage every ship he could from the bottom of Scapa Flow, before giving up after 8 years £10,000 worse off than when he started. For all his drive and determination his financial skills were lacking and his inefficient, pioneering methods just never paid back.

Other Scottish businessmen, including those of Alloa Shipbreakers and salvage diver Tom Mckenzie formed Metal Industries Ltd, who carried on were Cox left off, with more efficient, refined techniques and sensible business practices that saw things pay off in a big way.

The last Scapa ship raised by Metal Industries was the Derfflinger, who spent WW2 beached upside down alongside the disarmed old battleship HMS Iron Duke with was the Scapa HQ ship. The salvage men aboard saved the Iron Duke after she was nearly sunk in an air raid.

Derfflinger was floated into a submersible dry dock and towed to Faslane after the war for scrapping. The Faslane shipbreaking yard later became the home of the Polaris "nuclear deterrent".

One of Metal Industries' many improvements on the salvage process was to rapidly sink the ship as soon as they had raised it, to crush and concertina the protruding superstructure up inside the hull, removing most of the underwater obstructions that plagued Cox.

Thead as a page 🧵📄 "The last voyage of the Battlecruiser "Moltke". Or how a German Warship nearly destroyed the Forth Bridge almost 10 years after the end of the war" threadreaderapp.com/thread/1550936…