Difference between revisions of "Diving the Cape Peninsula and False Bay/Highfields"
Revision as of 10:48, 26 November 2011
The Highfields was a British four-masted steel barque commanded by Capt E.R. Dunham. The vessel was lost on 14 August 1902 after a voyage from Cardiff to Table Bay with a cargo of coal. Survivors reported that she had been in a severe storm off the Cape and had lost most of her canvas. Her decks were awash but she managed to reach Table Bay under small sails. It seems her crew and captain were desperate to find shelter.
The German steamship Kaiser was at anchor just outside the breakwater when the Highfields came out of the dark (just after midnight) and hit her anchor chain. The Highfields briefly lay across her bows before being blown off. The Kaiser was not damaged at all, but the Highfields sank within 2 to 5 minutes of the collision with the loss of 23 crew including the master and second mate.
This site is not in a Marine Protected Area. A permit is not required. The site is mostly within the traffic separation zone between the main deep water channel and the inshore traffic zone, and the bows of the wreck extend a few metres into the main harbour approaches lane
"Highfields" is the name of the shipwreck at this site.
Maximum depth is about 22m, and the top of the wreckage is at about 18m.
Visibility will be at its best during or after strong south easterly winds, and may exceed 20m, but will more likely be around 8 to 10m. If the wind stops and the sun shines for a few days, plankton bloom will reduce visibility, and if westerly winds blow, they will usually also result in poor visibility, which could be less than a metre on a bad day.
The wreck lies in roughly 21m depth on low flat rock between slightly higher ridges to the north and south, with small patches of sand and gravel, and is fairly intact but is up-side down so it is mostly hull plating that is visible, Around the sides there are a few places where one can see into or under the hull, and her huge anchors lie just off the bow.
The wreck is aligned almost east-west geographically. The bows are to the east, and a section of bow with the forefoot and a short length of keel has broken off and lies on the bottom on its starboard side. This section carries the anchor winch, which is quite large and still largely intact. Scattered around this section are several anchors of the traditional shape, some with stocks deployed, others with stocks stowed and a couple with missing stocks. They may not all originate from this wreck, as there are about 6, of various sizes, which seems a bit much, and the area has been an anchorage for centuries, so it is entirely possible that some of them were from other vessels which were fouled on the wreck and lost.
A short distance further east there is a section of what appears to be the bowsprit, a large diameter iron tube with fittings appropriate to that origin. It is only a few metres long, and is aligned roughly with the length of the vessel.
Slightly to the west there is a rather broken up section which contains a large mass of chain, rusted and concreted by coralline algae and other growth into a solid mass with the other wreckage and two sustantial bollards, and further west the main section of hull has collapsed, leaving mainly low sections of topside plating and frames standing upright to the sides.
As you continue to the west you will come upon the more intact section of bottom, which has subsided along the sides, leaving the south side partly open, and the north side closed by a long upright section of topside plating. The bar keel is clearly visible along the full length of this section, and terminates near the stern where the plating has collapsed completely. This leaves an arch shaped opening nto the hull spaces, but it is quite low and there is a lot of debris inside.
A short distance further west, and partly overlapping the main section of collapsed hull, the sternpost and deadwood section of the run has broken off and lies on its side on the north side of the wreck. The sternpost still has visible gudgeons and lies transverse to the centreline of the wreck. A large section of the rudder, still carrying several pintles, lies partly under the sternpost. A few metres south there is an object which may be the rudder post, and with it what appears to be the rest (top half) of the rudder.
The south side of the wreck has more scattered debris than the north side, which is basically straight. Among this debris are some components that look as if they might be parts of a small steam engine, possibly used to power the winches. There are also some more fragments of iron spars, and an unidentified artifact which was named the "Maypole" by divers. It is a cylindrical object a couple of metres long, with a flange and a sharp spike at the one end, with two more or less spherical blobs. The one blob was described as "ornate" by the diver who took the photo.
Geology: Pre-Cambrian sedimentary rocks, probably of the Tygerberg formation, with scattered patches of sand and gravel. The rock is quite hard and tends to weather in rectangular blocky forms. Strike probably north/south. Dip not known.
The site is exposed to wind and waves from the north west and west, so should be dived when the swell is fairly low and fronm the south west to south east, and is often good in south easterly winds in summer. The site is reasonably protected from south westerly swell, particularly if the period is short (10seconds or less)
The site is usually at it's best in summer but there may also be occasional opportunities in spring and autumn.
This is an area which sometimes has upwellings of cold clear water, caused by strong south easterly winds, resulting in good visibility for a short while, usually followed by a plankton bloom, as the upwelled water is rich in nutrients. The plankton will reduce visbility, particularly near the surface, though there may be reasonable visibility at depth, often below a thermocline, but light levels may be low.
This site is only accessed by boat as it is quite far offshore and at the edge of the shipping lane at the entry to Cape Town harbour. Take care to remain outside of the shipping lane during the dive.
The site is about 2.2km from the Oceana Power Boat Club slipway
Marine growth on this wreck is relatively sparse. The dominant organisms seem to be coralline algae, mostly of the encrusting types known locally as "pink paint". You can reasonably expect to see Hottentot seabream, as they are almost everywhere over reef in this region, but probably not much else in the way of fish. There are also some sea squirts and other ascidians, and a few starfish and other echinoderms, but this is not a dive site for the enthusiastic invertebrate spotter.
Inverted wreck of a 19th century iron sailing ship. The wreck is in an interesting condition, where it is sufficiently intact for a diver to work out where on the vessel you are, but sufficiently broken up to make this a bit of a challenge. There are several large anchors, a large winch, some fragments of the rig, the rudder, two sets of bollards and some enigmatic pieces of machinery, besides the large amount of hull that is still more or less intact, and the usual scattered plates and frames around the perimeter and lying in heaps near the hull. The wreckage is unusually bare of marine growth for its age, and is largely coated with pink encrusting coralline algae, much like most of the surrounding reef, and in many cases the first indication that you are looking at wreckage is that it has unnaturally straight lines, and space underneath. The hull has several areas where it is possible to see some distance under the plating, and one wonders what may be found in these protected areas on a day with good visibility.
There is not a great deal for the macro photographer. Most of the features of this site are fairly bulky items of wreckage, and will best be photographed with a wide angle lens, The visibility is often quite poor, with lots of particulates to cause backscatter, so either long strobe arms or natural light will give the best results. The wreck is fairly monochrome anyway, so the loss of colour is less important than at many other sites in this region. you have the choice then of monochromes in pink and brown with artificial light, or greens with natural light. If the visibility is good the light levels should be adequate for natural light wide angle work.
No specific route recommended. It is possinble to circumnavigate the wreck during a dive. Both ends are worth a visit, and the south side seems to have more interesting details and gaps to see into the space inside the hull. For divers uncertain of their navigation skills, it is suggested to clip a reel line to the shot and head off to one of the ends via the south edge of the hull, then return and do the same to the other end. In this way most of the wreck can be seen and the position and distance to the shotline will always be known, enabling a safe ascent.
Diving the Highfields is especially tricky as she lies immediately to the west of and partly in the entrance channel to the harbour. One needs to inform Cape Town port control of the dive and then devise an ascent system that prevents divers drifting east into the channel during ascent and while on the surface. A shot line placed on the stern (furthest point away from the channel) with its buoy attached to a second line to an anchor placed some distance further west has proved workable. Another way is for divers to tie a biodegradable sacrificial ascent line to the wreck which they hold onto during ascent and on the surface. They then let go of the line once the dive boat gets to them. In any event, diving the wreck with a west wind blowing or with an appreciable current from the west is not advisable.
It is essential to be able to find your way back to the shotline, or deploy an upline and DSMB for ascent, as you must avoid getting into the shipping lane, particularly during the ascent, as at that time the boat will not be able to assist if a ship comes through. Do not assume that large ships will be able to avoid your DSMB, even if they see it. Altrnatives for finding the shotline include bottom lines, and effective use of a compass, bearing in mind that the wreck is steel, and will affect accuracy of a nearby compass. Navigation using landmarks should be possible if the shot is suitably placed, but this will depend on visibility.
The site is not suitable for entry level divers due to the depth and skills requirements.
DSMB is strongly recommended so that the boat can monitor your position if you must ascend away from the shotline. Jersey upline (disposable, biodegradable line for ascent) recommended to prevent drift if ascending away from shotline.