The dive site Oakburn and Bos 400 is a recent wreck overlapping a historical wreck, on a shoreline rocky reef in the Karbonkelberg headland area on the Atlantic seaboard of the Cape Peninsula, near Cape Town in the Western Cape province of South Africa.
The site is mainly interesting for the wreck of the Bos 400, and what remains of the Oakburn. The marine life is better represented at other nearby sites.
The position is unmistakeable as the Bos is clearly visible above the water for a long distance. The Oakburn is to the south west of the Bos, almost under its stern, and somewhat deeper.
This site is in a Marine Protected Area (2004). A permit is required. The site is within the Karbonkelberg restricted area.
The "SS Oakburn", a British cargo steamer of 3865 tons, was wrecked in fog on 21st May 1906, on a voyage from New York to Sydney. Two lives were lost. Its cargo included railway lines and equipment, glassware, sewing machines, musical instruments, oil and paper. The Oakburn has pretty much fallen apart, and on 27 June, 1994, the crane and pipelaying barge "Bos 400" broke its towline during a north westerly gale while under tow by the Russian tug "Tigr", and ran aground virtually on top of the older wreck. Unsuccessful efforts were made to reconnect the tow and salvage the vessel. The Bos is also starting to break up and it is possible to do some penetrations on the submerged sections. Length of the Bos 400 was about 100m and displacement about 12000 tons. The helicopter platform collapsed in September 2010, and the central section of the hull a week or two later. The crane base remains firmly aground and upright on the inshore rocks.
Maximum depth on the Oakburn is about 22m, mostly shallower. The Boss is mostly shallower, but is scattered down the slope to at least 20m. Parts of the wreckage extend above the water at all tides.
Granite corestone point with two steel wrecks.
The older Oakburn lies deeper and further to the west, to the stern of the Bos, among moderate to large boulders and outcrops. The wreck is severely broken up and the plates and framing are fairly mangled, though there are a few places a diver can get under them. There are three scotch boilers grouped to the northwest of the exposed part of the Bos, on sand bottom at 21m. The top of the boilers is at about 18m depth.
The recent Bos 400 is largely intact and a large section is still perched high on the rocks, with only part of its upper deck awash. There is a large space under the stern which can be penetrated like a cavern, which is fairly free of snags and is open along a wide area. Other penetrations on this section may be possible in calm weather, but swell causes powerful surge around and through the openings in the stern. The sides were clad with heavy vertical timbers for protection when laying pipes.
In September 2010 the section of the hull which had supported the helipad broke away and slid down and to the north, and the helipad fell off and came to rest on the reef slightly to the north at an average depth of approximately 13m. Various components of the wreck now lie on the bottom in this area, some of which are easily accessible for penetrations.
Later in September 2011 the middle section of the hull also broke away and slid down to the north, and appears to have broken up considerably. The debris includes an area just adjacent to the remaining exposed part with the crane, which is covered with torn and twisted plating, and sections of pipe of various diameters. There are also a few 50 litre gas cylinders and the armature of a large electric motor.
To seaward there is a large pipe with a surrounding cylindrical casing with perforated ends, a section of superstucture which is now upside down and a small crane base with a box section boom. There is also a large structure of heavy tubing with a sliding block and what appears to be a hydraulic piston, and at the end of the structure a large conical opening. This may have been part of the pipe-laying equipment.
The end section which supported the helipad is only slightly submerged. The deck is about 5m deep, and has a few large openings into the interior. This section is rectangular in plan, and is strongly wedged in place by several rocks which have penetrated the bottom plating, locking it in place on top of the boulders.
The wreck is now a considerably more interesting dive site than when the vessel was intact, as there are now large number of interesting artifacts and structural components lying around, some of which can be penetrated.
Geology: Granite outcrops and boulders of the late Pre-Cambrian Peninsula pluton
The site should preferably only be dived on calm days as it is in an exposed position. There can be a very strong surge through the shallower wreckage.
The site is exposed to swell from the west, and protected from wind and chop from the south east. The site is usually at it's best in summer but there may also be occasional opportunities in autumn and early winter.
This is an area which sometimes has upwellings caused by south easterly winds, which result in cold clear water, and may be followed by a plankton bloom, which will reduce visibility again
The site is only accessible by boat as there are no roads in the area. The site is about 7.4km from Hout Bay harbour.
Marine life is typical of the area but not particularly noteworthy. A careful search will reveal quite a lot of colourful corals, sponges and anemones sheltering in crevices.
Historical and recent wrecks. The Bos is largely intact, though it is deteriorating rapidly as it is in the surf zone. Penetration is possible, but can be tricky in the shallow sections due to the surge.
There are no macro subjects worth setting up for. This is a site for wide angle photography, and on a good day the lighting is reasonable.
No recommendations available at present.
Cold water, Strong surge. Ragged wreckage. Probably a high risk of entrapment in some sections of the Boss.
No special skills required for non-penetration dives.
A light will be useful as there are lots of holes and openings to look into.