As with most of the Scapa Flow wrecks, local dive boats maintain a buoy line on the Brummer, which lies in 33m. Here the line is usually attached just forward of the break in the hull left by salvage work on the engine room (1).
Immediately beneath the line is the centre main gun turret (2), just a 5.9in gun and a bit small compared to the nearby battleship guns, but nevertheless worth a look.
The nice thing about the cruiser turrets is that they are open at the rear, making it easy to have a good view of the breech mechanism and controls.
This turret is also a useful navigation aid, with the gun pointing towards the rear of the ship; the opposite direction is the bows.
Following roughly along the centre-line of the ship, immediately forward of the gun is a hole where a funnel used to be (3). This is not a practical way to the engine room, as the flues were secured by armoured gratings as a defence against plunging shells.
If you want to get in among the remains of machinery, your best route is further back in the salvage hole.
Next is the navigation bridge, an open structure of platforms and latticed supports (4). The mast is towards the forward end of the superstructure, unlike the cruisers KÅln and Dresden, where the mast is at the rear of the superstructure.
A solid-looking cylindrical structure with slit windows in front of the bridge is the armoured conning tower (5), where the ship would be controlled during battle.
On the roof is the T-shaped central rangefinder for the ships guns. An arrangement of lenses and prisms would be used to calculate range from the parallax between the images viewed from opposite ends of the rangefinder. However, these optics were removed in Germany before the Brummer was interred in Scapa Flow.
Continuing forward, in front of the conning tower is the forward gun turret, similar to the amidships gun, with the gun barrel pointing about 20Â to port, and an open back (6).
The last feature before the bow is a pair of anchor capstans (7), with lengths of chain draped across the gaps to the chain-locker and hawse pipes. The last few metres of the bow has broken and twisted towards the seabed, leaving a hole back beneath the bow deck (8).
If you are into a bit of wreck penetration you can find your way back amidships between decks. Its not as complex as it sounds, because many internal bulkheads have collapsed and hatches between decks are all open.
Light enters from above where plates in the hull have been removed or come loose with age, also providing easy routes out before the break (9).
On the way you will pass the mechanisms driving the anchor capstans and the forward gun. The space round the anchor capstans is interesting; it looks as if it was designed for a gang of sailors to work the capstan by hand if the powered mechanism should fail.
Back at the starting point (1), there is a choice of ascending and saving the stern of the Brummer for a later dive, or continuing aft.
The debris here is quite complex, but heading towards the keel you can find piles of coal in one of the coal bunkers (10). Like most German warships of the era, the Brummer was powered by a mixture of oil-fired and coal-fired boilers. There are also scattered lumps of coal on the seabed (11).
From the aft side of the break to the stern, the decks have started to peel away from the hull (12).
Some areas of deck are complete, and in other areas the deck plates have also peeled clear. The overall confusion makes it hard at times to tell just which deck you are following.
The Brummer was a mine-laying cruiser, with an internal rail network used to move mines about the ship and push them out across the stern deck and over the side. Its a similar arrangement to that of the mine-laying freighter Port Napier (Wreck Tour 12, February 2000), albeit on a smaller scale.
Having swum through the ship between decks it is easy to imagine where the mine tracks would have been, but no one I have spoken to has seen the actual tracks. Maybe they were removed at some point in the Brummers life, or perhaps they were salvaged.
The rear superstructure is partially buried beneath debris from the hull, the location being given away by a protruding section of mast (13).
Further towards the stern, the upper stern gun turret is partially obscured by a fallen hull plate, making a triangular swim-through past the gun (14).
Behind this and one deck down, the other stern turret is in the open (15). Both are similar in construction to the earlier turrets with an armoured cover over and an open rear, and both are also pointing slightly to port from the stern,
Finally there is a single anchor capstan (16), still firmly connected to the stern anchor that is nestling in tight against the stern of the hull.
From the stern it is easy to follow the port side of the deck back to the break, exploring some of the gaps between decks on the way (17). Once at the break, it can take some thinking to get across to the buoy line and ascend. If time is pressing, releasing a delayed SMB can be a lot more convenient.

Thanks to Matt Wood, Andy Cuthbertson and many members of Tunbridge Wells BSAC.

For her size she was fast. When she finished her sea trials in 1916, the German Navy knew that the 4,308 ton light cruiser Brummer was going to be as good as the other eight in the Bremse class, possibly even faster as her 33,000hp turbines and twin props gave her a steady top speed of 28 knots.
It was a speed that she soon put to use, writes Kendall McDonald. Though planned as a fast minelaying cruiser, the 462ft-long Brummer quickly teamed up with her sister ship Bremse and started harassing the Allied Scandinavian convoys with her 5.9inch guns (two mounted at the stern and two at the bow).

The Two Bs, as they were known to Norwegian convoy commanders, carried out a massacre of nine Allied and neutral ships on 17 October,1917, after sinking the escorting destroyers Mary Rose and Strongbow. The two cruisers worked together for the rest of the war. Their names suited their actions - Brummer is a wasp in German, and Bremse means horsefly.

Despite the number of actions in which they took part, both of these armour-plated warships went through the rest of the war unscathed. After they were scuppered with the other light cruisers in Scapa Flow, only the Bremse was salvaged.

Approaching the central 5.9in gun turret at the start of the dive

the backs of the gun turrets are open, allowing easy inspection of the breech mechanisms

below decks the mechanism looks as if it might have been designed for manual power in an emergency

one of two anchor capstans at the bow

looking along the rearmost 5.9in gun

GETTING THERE: Ferries to the Orkney Islands run from Scrabster, Invergorden and Aberdeen. The longer ferry routes cost more, but have the advantage of shorter road journeys. The Scrabster-to-Stromness ferry is accustomed to divers and has a system for carrying dive gear for foot passengers, so you can easily leave your car on the mainland. Coaches from Inverness to Scrabster are scheduled to fit in with the ferry sailings. It is also possible to fly in to Kirkwall.

TIDES: The Brummer can be dived at any state of the tide.

HOW TO FIND IT: The chart co-ordinates 58.53.83N, 3.09.15W (degrees, minutes and decimals). The Brummer is easy enough to find from the co-ordinates with a GPS and echo-sounder, especially as there is a small buoy attached.

DIVING AND AIR: Most diving in Scapa Flow is from large hardboats, many offering liveaboard floating bunk room accommodation. Boats are generally based in Stromness, although they may tie up overnight at other harbours. Air is provided by on-board compressors, and nitrox can be mixed on-board most boats for an extra charge. Air, weights and cylinders are usually included in the price, so travelling light and using the boats equipment is an option. I dived the Brummer from Jean Elaine, skipper Andy Cuthbertson, 01856 850879.

LAUNCHING: If you want to ferry your own boat across, there are a number of small slips in Scapa Flow. The nearest to the Brummer is at Houton. Scapa Flow is a working harbour and you will need to arrange permission to dive in advance with the harbourmaster.

ACCOMMODATION: Sleep on board the boat, or stay ashore in a local hotel or B&B. There is a camp site in Stromness, but I would not recommend camping in the Orkney climate. Orkney Islands Tourist Board, 01856 872856, www.orknet.co.uk.

QUALIFICATIONS: Experienced sport divers who are capable of doing some decompression. Nitrox can be an advantage to get the most out of this wreck.

FURTHER INFORMATION: Admiralty Chart 35, Scapa Flow and Approaches. Ordnance Survey Map 6, Orkney - Mainland, Ordnance Survey Map 7, Orkney - Southern Isles. Dive Scapa Flow, Rod Macdonald. The Wrecks of Scapa Flow, David M Ferguson. The Naval Wrecks of Scapa Flow, Peter L Smith. Shipwreck Index of the British Isles vol 4, Scotland, by Richard & Bridget Larn.

PROS: A little different to the more more popular KÃln and Dresden.

CONS: Scapa Flow is a long way to travel for most UK divers.