This late WW1 U-boat victim sank off north Cornwall, where the good visibility makes the wreck a bit of a treat for divers, says JOHN LIDDIARD. Illustration by MAX ELLIS
CATCH SOME GOOD CONDITIONS IN MAY, just before the algal bloom or “May water” arrives, and the visibility can be stunningly good. Where better to enjoy it than off the north coast of Cornwall?
So for this month’s tour, we head out west from Newquay to the World War One wreck of the 2790-ton steamship Orfordness. It’s a comfortable 32m deep on a low-water slack, so most experienced divers can enjoy it.
As usual, our tour begins by the boilers (1), but don’t be surprised if the shot goes in late. Chris Lowe, skipper of Atlantic Diver, likes to leave it until the last minute before shotting the wreck, so the weighted line is less likely to be dragged by the big groundswell.
The port boiler rests in its mounts, while the starboard boiler has rolled slightly towards it, narrowing the gap between the two to be too small for a diver to swim through, though cosy enough for cuckoo wrasse to weave in and out of the gorgonian sea-fans.
The way the starboard boiler has rolled can be seen from the angle of the three fire-boxes on the front end.
The entire hull and deck have flopped to port, so that the port side of the hull is beneath the mostly level main deck, while the starboard side stretches out to the south-east. Just forward of the boilers and to either side are sections of deck with intact bunker-hatch coamings.
Among the debris in between is a set of steps (2) that would have once led from the stoke-hold to the main deck.
Continuing forward, a large cargo-winch (3) spans the deck behind the second hold, then another cargo-winch begins the area of deck between the two forward holds.
To starboard, a spare stockless anchor (4) is secured to the deck.
On the corresponding space to port, an older Admiralty-pattern anchor (5) is secured to the deck, with the stock removed and secured alongside.
A larger anomaly is a set of steps lying right on the port side of the deck. Perhaps they washed back to here when the ship sank, or when the bow broke off.
The area between holds ends with the cargo-winch that would have served the forward hold (6).
Crossing the hold, the bow has broken off and rests on its port side. Behind it, debris between the bow and the main deck includes bollards (7), cable-drums and sections of railing.
A big anchor-winch (8) stands on one end, spanning most of the width of the bow deck. The chains have gone, but the hawse-pipes (9) remain intact in the forward part of the bow deck, with the anchor stems visible inside.
On the starboard and now upper side of the bow, the stockless anchor (10) is pulled tight into the hawse-pipe.
To return to the aft half of the wreck, the easiest route simply follows the port side of the deck (11).
Just aft of the boilers, another bunker-hatch (12) marks the aft end of the bunker space that would have run along the side of the hull. A similar hatch can be found on the starboard side.
The triple-expansion engine (13) has broken and fallen to port, leaving the crankshaft exposed and the cylinders mostly cracked open or destroyed, though the crowns of the pistons are still easily identified among the debris.
Still on the port side of the engine, the circulating pump (14) stands upright just out from the remains of the low-pressure cylinder. A little further out and just aft is the helm (15), which would originally have been above and forward of the boilers.
Back on the centre-line of the ship, as marked by the crankshaft of the engine, the thrust bearing connects the engine to the propeller shaft, leading aft into the propeller-shaft tunnel (16). Above the tunnel, a pair of winches (17) mark the line between the third and fourth holds. Also from the deck between the aft holds, a cable-reel (18) can be found part-buried a little to port.
Resuming our route aft, the propeller-shaft soon reappears from its tunnel (19), then breaks where the keel narrows for the stern (20). In fact the whole wreck breaks here, with a trail of debris leading out to the west.
Just off from the port side, the aft mast (21) angles out from between the holds.
A search outwards reveals a section of hatch-coaming (22), then the rudder (23). A metre or so from the base of the rudder, the base of a propeller blade stands up from the sand. The tip of the blade is below, and the base has sheared off close to the hub.
This helps to illustrate how the Orfordness broke as it sank. When the vessel was torpedoed by U60 on 20 July, 1918, the torpedo struck aft and the Orfordness went down fast by the stern.
The stern would have hit the seabed first, the propeller and rudder digging in. The blade and the rudder would have sheared off, as any remaining headway and the tide continued to move the ship forward, while skewing it to starboard.
Next, more of the stern would have broken loose as the wreck settled, with the main body finally settling some 30m further on.
I have to confess that I have not seen the big chunk of stern that is missing from our tour. When I was sketching the wreck I made several sweeps out from the main body, but ended up running out of bottom time and slack water before I could find it, so had to return to the shot to ascend.
Reports are that it is off somewhere out to port from the aft hold (24).
GETTING THERE: Follow the M5 to Exeter, then the A30 past Bodmin to Indian Queens. Then turn north on the A392 to Newquay.
HOW TO FIND IT: GPS co-ordinates are 50 24.685N, 005 11.212W (degrees, minutes and decimals). The bow is to the north-east, and the wreck a few metres from a 32m seabed at low water.
TIDES: In the big tides off the north coast of Cornwall, slack water is essential. It occurs half an hour after high and low water Newquay, with the low-water slack being considerably shallower.
LAUNCHING Slip at Newquay.
QUALIFICATIONS: Suitable for PADI Advanced Open Water or BSAC Sports Diver. It’s an ideal depth to extend bottom times with nitrox.
FURTHER INFORMATION: Admiralty Chart 1149, Pendeen to Trevose Head. Ordnance Survey Map 200, Newquay, Bodmin & Surrounding Area. Dive The Isles of Scilly & North Cornwall, by Richard Larn & David McBride
PROS: Typically good visibility on a seabed of hard granite sand.
CONS: Just too deep for PADI Advanced Open Water Divers without a deep speciality.
Thanks to Chris Lowe.
Appeared in DIVER May 2011