There are large patches of red tide in False Bay, and no wind to clear them up. For this reason I’ll decide on Saturday whether we’ll be boat or shore diving on Sunday. I have students, so we’ll keep it relatively shallow either way. Let me know if you want to keep in the loop for the weekend dives. There’s been bioluminescence at the Strand beach this week, so keep an eye out for it around Fish Hoek beach during the evenings if the red tide persists.
Spring high tide at Fish Hoek beach
Tidal documentary
Don’t forget the screening of Tidal at St James beach on Thursday 7 March. RSVP here.
One of the most spectacular shipwrecks I’ve ever seen was that of the 100 metre long unmanned barge Margaret, which ran aground at Jacobsbaai on the West Coast on 24 June 2009. Margaret was carrying two halves of a floating dry dock and twelve river barges (positioned atop each other in side by side pairs, with two rows of three at the bottom). She was under tow by the tug Salvaliant from the Chinese shipyard where everything was manufactured, to Rotterdam. The barges were destined to transport cargo up and down the navigable rivers in Europe. During a winter storm, the tow parted, and Margaret and her cargo ran hard aground on the rocky reef just outside Jacobsbaai.
The eight storey pile of barges in December 2009
Salvaging the barges proved to be an almost intractable problem, so Margaret was still sitting firmly a couple of hundred metres off the beach when Tony and I visited six months after her grounding, in late December 2009. The stack of barges and two halves of a floating dry dock (the blue parts of the structure in the images) was clearly visible from a great distance. The sight was even more incongruous than that of the Eihatsu Maru aground on Clifton beach, which was a wreck-lover’s dream (but unfortunately not a permanent arrangement).
View of the barge Margaret from atop the sand dunes at Jacobsbaai
I wish I’d taken a picture of what the wreck looked like as we drove down the hill into Jacobsbaai, but you can see one here if you scroll around a bit. It looked like an office block rising out of the ocean. The wreck was so large that it was visible from almost every point in the sleepy town, and the brain struggled to make sense of the sight. It’s clear from the images what a challenge it must have been to tow the barge in the wind, as the forty to fifty metre high, perfectly flat sides of the stack must have provided tremendous resistance in a gale.
Portion of the barge wreck at Jacobsbaai
The owner ran out of money to continue salvage in February 2010, and Margaret was becoming increasingly damaged and unstable as time passed. The risk of the upper barges coming loose during another storm, and drifting away to cause a hazard to other ships or coming ashore on the beach, was great. It was decided by SAMSA to persist with an attempt to reduce the wreck, at taxpayers’ expense. Any money obtained by selling off the salvageable barges would go towards defraying costs.
During the salvage work on the barge Margaret
Salvage
Tony and I visited the wreck again in April 2010, after the demolition that freed six of the topmost barges. The seaward wall of the upper piece of floating dry dock, weighing 91 tonnes, had been cut away to allow the barges to slide off freely.
The remains of the barge Margaret in April 2010
Over two tons of explosives were used in total. Small (125 kilogram) explosive charges were set off one after the other to create a ripple effect that dislodged the top six barges. These were towed to Saldanha, and then sold.
The wreckage of Margaret and her cargo in April 2010
If you like reading court judgments, here’s one in which the owners of the barges attempt to claim damages (massive ones) from the owners of the tug Salvaliant. There’s also a great collection of photos of the wreck in her various incarnations here.
The wreckage of Margaret in late April 2010
In late April 2012, Tony snapped this lucky shot of two of the barges leaving Simons Town harbour under tow. They’d been moored against the harbour wall for at least a month, to the consternation and fascination of the local paddling community.
Two of the salvaged barges leaving Simons Town harbour in April 2012
The remains of Margaret and her cargo were further demolished down to sea level and below, and now comprise an artificial reef. Fortunately there was no fuel or other pollutants in the stack of barges, which made the process significantly less polluting than it might otherwise have been.
The barge Margaret today
Tony and I visited Jacobsbaai to check out what remains of Margaret and her cargo in September 2018. The path to the wreck, which was formerly blocked off by hazard tape and “salvage in progress” signs, is wide and easily walkable. One can go right up to the rocks and view the wreckage from reasonably close up. Watch your foothold here, as it can be slippery and the rocks aren’t all firmly packed.
The remains of the barge Margaret and her cargo
Look out for a small memorial to one of the salvors, who passed away in an accident on the wreck during the course of the salvage operation.
Sharp wreckage sticking out of the sea
Parts of the wreck look like shark fins in the water, and it is possible that even more of it is visible at low tide.
The remains of the barge Margaret in 2018
You can find the wreck by turning off the R399 towards Jacobsbaai, and continuing towards the coast until the road becomes gravel. Carry on this road, and when you reach a T junction take a right turn to circle around the tiny, sheltered bay in front of you. When you can’t drive any more – there will be a small housing development in front of you – park the car and either walk up the steps on the dune to get onto the beach, or, preferably, through the houses. The paved area will give way to a wide gravel path that the salvors used to access the wreck. Continue straight along it and you’ll soon spot the wreckage on the rocks ahead and to your right. Co-ordinates are approximately -32.964140, 17.881612.
After a successful Back a Buddy campaign, Shark Spotters launched their free shark safety smartphone app in the summer of 2016. The app has had excellent uptake by water users of all stripes, but I’d like to draw it to your attention in case you aren’t familiar with the ways in which it can make your beach life better and safer! Whether you’re a surfer, a diver, an ocean swimmer, a beach comber, or someone who looks forward to long summer days under an umbrella on the sand, the Shark Spotters app can make a difference to you.
The list of Shark Spotters beaches
Shark Spotters operate at eight beaches around the Cape Peninsula: four (Muizenberg, St James/Kalk Bay, Fish Hoek & Caves, Kogel Bay) year-round, and another four (Glencairn, Clovelly, Monwabisi and the Hoek, Noordhoek) from October to April, during the warmer months.
The app allows one to set a home beach – you can see from the image above that mine is Fish Hoek – and when you start the app, you’ll get information for your home beach immediately. Tapping on the home beach block at the top of the screen (where it says “Tap for more”) brings one to a series of screens that you can navigate through by swiping the bottom block on the screen.
Information on recent sightings at my home beach
Weather and sea conditions
Information on marine life activity
Information on beach facilities
Beach conditions video
Shark sightings history
The information provided is extensive. You can see information on the last three shark sightings at your home beach, the weather and sea conditions (temperature, wind direction, tides, moon phase, swell), and information on what marine life is in the area. This latter information is not a nice to have so you can look out for dolphins from shore, but an important indicator of the likelihood of a shark being in the area. Dolphins, rays and schools of fish can draw white sharks, while sunfish (and even seals) may be mistaken for a shark when viewed from a distance by an untrained observer.
There’s also information on what facilities are available at the beach, and a short video for each beach, usually taken each morning, showing the prevailing conditions.
All this information is available for all the Shark Spotters beaches, not just your home beach, and you can view a different beach by selecting it from the list that appears under your home beach on the home screen.
Digging into the app, you can find a detailed list of all the recorded shark sightings, and in the settings you can turn notifications of sightings on or off according to your preference. I have them switched on, because I like to be reminded of a world outside the office.
Shark Spotters app menu options
The further menu options, shown above, give you access to a large amount of data about the Shark Spotters program, the exclusion net at Fish Hoek beach, how the flag system works, great white sharks, and more. Most of the menu options also provide links to more detailed information online, if you want to know more.
A recent low tide visit to the beach at Platboom near Cape Point, on the Atlantic coast of the peninsula, enabled us to watch a troop of Chacma baboons (Papio ursinus) foraging for limpets, mussels and other marine snacks on the rocks at low tide. The baboons bite the tops off the limpets with their formidable incisors, or pry them from the rocks intact to get at the protein-rich flesh. They also eat mussels.
The amount of time the baboons are able to spend foraging on the shore is largely determined by the height of the tide, and by weather conditions. As a result, the amount of time the baboons spend seeking marine food sources is small compared with the time they spend looking for roots, bulbs, insects, berries, and small animals.
Low tide at Platboom
These baboons are part of the Kanonkop troop which ranges freely in the Cape of Good Hope section of Table Mountain National Park and whose home range does not bring them into conflict with humans (or, as a rule, allow them access to any anthropogenic food sources). They were completely uninterested in us and our vehicle, unlike the baboons we see further up the peninsula around Millers Point, for example.
Autumn is a good time for False Bay diving! False Bay is currently pleasant, not too cold and the weekend does look decent after the latest weather updates. My plan is shore dives on Saturday, when it will be a little more windy, and boat diving on Sunday. Let me know if you’d like to get in the water.
Spring low tide at Muizenberg
Shark Spotters binocular fundraiser
Don’t forget to donate to the Shark Spotters crowd funding campaign to raise funds for new high powered binoculars for the spotters. Shark Spotters does fantastic work – read more about it here and here. You should also make sure you download their very cool shark safety and beach information app – available for both Android and iOS.
Life’s a Beach: Your Round-The-Coast Guide To South African Beaches – Ann Gadd
Compliments of the season. If you’re contemplating which beach to head to for tomorrow’s traditional Boxing Day beach outing, a venerable South African institution, I have just the book for you. The product of a mammoth investment of time (which couldn’t have been all bad) and distance travelled, Life’s a Beach is a handy guide to (possibly, probably, almost) every single beach along South Africa’s coastline.
Life’s a Beach
Each pair of facing pages covers a stretch of coast, and beaches are rated for surfing, alongside information about swimming, kiteboarding, wake boarding, kayaking and canoeing, diving, fishing and hiking. The scuba diving information for the sites around the Cape Peninsula, with which I am familiar, is reasonable, but of necessity very abbreviated owing to the book’s format and primary focus. It goes without saying that you should seek out some local knowledge before diving in an area you haven’t visited before.
Unique experiences and best kept secrets (no longer – haha!) are highlighted, as well as the presence of braai and picnic facilities. Tips on where to go for sundowners are also included. Child friendly activities are mentioned where applicable, too.
Access tips, as well as warnings about rips, pollution, sharks (thank you Shark Spotters!) and whether a beach has Blue Flag status round off the comprehensive information that is provided in a handily concise manner. This book will be extremely useful when you’re visiting an unfamiliar stretch of South Africa’s coastline, and particularly invaluable when it’s a little known and less popular beach.
Get a copy of the book here, or here if you’re outside South Africa.
Until recently, the last time I specifically went looking for the wreck of the Commodore II was in December last year, when I went to Milnerton lagoon beach to show visiting family the beautiful view of Table Mountain. At that time tides and waves had moved the wreck further away from the lagoon mouth, and she was lying on the sand at a spot that would be partially submerged at high tide.
Next time I went to look for the wreck, just after the Cape storm of 7 June this year, I couldn’t find it. A waiter at the Wang Thai restaurant on the beach told me he’d seen it all the way up at the old Wood Bridge at Woodbridge Island, and that people were removing pieces of the wreck and carrying them away. The storm surge had actually lodged the wreck partially under the old Wood Bridge (a sensitive National Monument constructed in 1901), and there was the potential for it to cause damage. There’s a picture of the wreck in this position on page 28 of this document (pdf).
Commodore II, secure for now
A few weeks ago Gerhard Beukes, a Milnerton resident, messaged me to say that he had secured the wreck about half way down the lagoon. It had been winched free of the Wood Bridge by Koos Retief, Area Biodiversity Manager at Table Bay Nature Reserve, and had floated back down the lagoon to settle on a sandbank near Gerhard’s home.
Chains and straps around the keelson
Mechanism by which the Commodore II is secured to the bank
Chains and straps around the keelson
Gerhard estimates that the wreck weighs about 25 tons, and with considerable personal effort and some financial outlay he has attached it to the lagoon bank, resting on the sandy bottom in shallow water, with chains and heavy lifting straps. The chain is secured to bolts attached to metal pipes sunk deep into the bank.
The Commodore II in Milnerton
The arrangement will prevent the wreck from washing around inside the lagoon and potentially injuring kayakers and other water users. It will also prevent it from washing out into Table Bay and becoming a semi-submerged shipping hazard, potentially lethal to vessels (something like the Seli 1 is when her buoy goes missing).
View towards Woodbridge Island
It’s also quite visible: if you walk or drive down Esplanade Street in Milnerton with Lagoon Beach behind you, you’ll come across the remains of the Commodore II next to the bank of the lagoon on your left. The wreck is over 60 years old, which means that under South African law it is protected and removing pieces of it is an offence. I hope that having many local residents’ eyes on the wreck will ensure it some measure of safety, even in the absence of any enforcement of the relevant laws.
How can you help?
To make sure the wreck does not come loose next time a large volume of water washes down the river and into the lagoon after heavy rains, it needs some further reinforcing in its current location. This could be done with a further 5 metre length of heavy duty chain, or (preferably) two loading slings, 25mm steel cable with rings or eyes on both ends. The harness needs to be capable of holding 25 tons of wood in place even under strain, and are necessary to completely stabilise the wreck.
If you have such items lying around unused at home, or are sufficiently moved and interested by the wonderful history of the Commodore II to make a donation, please comment on this post or use the contact form here, and I’ll connect you with Gerhard, the current guardian of the Commodore II.
Are you interested in shipwrecks that you can visit without going underwater? Read more about Cape Town’s visible shipwrecks here.
Last year the carcass of a smallish – about 8 metre long – humpback whale (Megaptera novaeangliae) washed up on one of the less-frequented beaches around the Cape Peninsula. I am very belatedly sharing some pictures of it, not least because one doesn’t often get an opportunity to examine an animal like this up close. I view these things with a mixture of sadness and awe; I think it’s easier to process objectively when the animal has already died. Strandings of live cetaceans can be extremely distressing.
Baleen plates
Some pieces of the whale’s baleen, which these animals use to filter their food from the water, were lying nearby on the beach. A large group of whales had been passing by the Atlantic seaboard in the days preceding the carcass washing up, and it may have been one of them.
The whale had been dead for a few days by the time it washed up on shore, but not so long that a lot of its skin had sloughed off (sometimes dead whales look white all over – as this whale’s belly does – for this reason). There was no obvious cause of death visible on the underside of the whale’s body. It was lying upside down so the top of its body wasn’t accessible.
It is possible that an anthropogenic cause (ingesting plastic, or a ship strike for example) could be responsible for this whale’s death. It’s also possible that the whale was sick or otherwise compromised and died of natural causes. Sometimes, when things in the ocean die, they wash ashore, and we find them.
Humpback whale on the beach
Humpback whale with human for scale
The humpback whale’s head
I’m not sure what ultimately happened to the whale’s remains – it was in the surf line when I saw it, being pushed back and forth by the waves. It might have been taken back out to sea with the tide. I would like to think that it was.
If you come across a dead whale – on the beach or out at sea – here’s what to do.
Colour front seen from Sunny Cove on 27 November 2015
Perhaps you have wondered what causes the patterns of strange coloured water in False Bay during the summer months. Perhaps you have dived in it, and wondered why sometimes you can’t see your hand in front of your face! Wonder no more – I am here to help.
Colour fronts
Frequent visitors to and residents of the shores of False Bay will observe that at certain times of the year, the ocean is marked by bands and arcs of sharply contrasting coloured water. This phenomenon is known as a colour front. In oceanography, a front is the interface or boundary between two separate masses of water. In this case, the water masses are easy to discern, because they are of different colours. There are usually other characteristics of the water on each side of the front that differ, too. Fronts are either convergent (the water masses are moving towards each other) or divergent. The presence of marine debris (like pieces of kelp) at the front boundary suggests that it is convergent.
Causes of colour fronts in False Bay
Prior to 2005, there was much conjecture about the causes of these fronts (including the usual pollution bugbear), but little evidence to support any of the theories. By sampling, the fronts were found not to be caused by pollution, or by plankton blooms in the surf zone. It was known that a colour front was most likely to occur in False Bay after a period of southerly or south easterly wind lasting a few days. October and November seem to be prime months for the phenomenon.
When a large, obvious colour front arose near Simon’s Town in November 2005 with milky green water on one side, and darker blue-green water on the other, researchers from UCT and IMT sprang into action, sampling the water on each side of the boundary so that they could measure its characteristics. Speed is of the essence in these situations; colour fronts can disappear quickly. The one in the picture below is busy decaying – notice the smudged boundary.
Colour front in north western False Bay on 13 November 2014
Measurements revealed that the milky green water overlaid the clearer, bluer water, down to a depth of 11-12 metres (this will vary from front to front). The milky water did not extend to the ocean floor. Scuba divers around the Cape Peninsula will be familiar with the experience of diving through two or more layers of water, with varying turbidity (clarity) and temperature! (Here is picture of Tony and Christo diving near Oudekraal in the Atlantic that shows what the boundary between two layers of water can look like.)
The researchers found that the milky coloured greenish water was full of fine, almost neutrally buoyant particles of calcium-rich sediment. The green-blue water contained much less calcium, but relatively more silicon, which would suggest the presence of diatoms (a kind of phytoplankton – you can think of them as teeny tiny plant-like organisms) or sand in the water. The origins of the calcium-enriched sediment in the milky water are interesting: one source is from the shallows (less than 30 metres deep) of north western corner of False Bay, where the ocean floor is made up of rocks that are rich in calcium carbonate (such calcrete and limestone), some areas covered by a thin layer of sand.
Milky-white water near Swartklip on 29 November 2014
The second probable origin for the particles of calcium-rich material is the interface between the sea and the land at the northern end of False Bay. The cliffs at Wolfgat/Swartklip at the head of the bay are made of calcrete, and at Swartklip the beach narrows to the extent that the cliffs erode directly into the water when the sea is high. Strong southerly winds create a wide (of the order of one kilometre) surf zone at Muizenberg and Strandfontein; a spring tide also adds to ideal conditions for the generation of a colour front.
The temperature of the milky water was found to be slightly (0.4 degrees Celcius) higher than the green-blue water. This measurement will also vary from front to front. The researchers speculate that the temperature difference could be because the milky water originated in the surf zone, which is shallower and therefore warmer, or because the high concentration of suspended particles in the milky water caused greater absorption of heat from the sun.
Colour front at Smitswinkel Bay on 24 October 2014
Summary
Here’s the tl;dr: strong southerly and/or south easterly winds, perhaps coupled with spring tide conditions, set up a very wide surf zone along the northern end of False Bay, which disturbs the sediment on the ocean bottom and drives the waves further up the beach than usual. Particles of buoyant calcium carbonate from the sea floor and eroded from the cliffs at Swartklip are lifted up into the water column, changing its colour to a milky-green shade. Wind-driven circulation patterns in the bay push the front from its original location in a southerly direction, towards Simon’s Town.
What to do?
Contrary to what your friends on social media may claim, not all colour changes in the ocean around Cape Town can be attributed to a giant sewerage plume. Hardly any of them can, in fact. In summer, the reason for the ocean looking green, red or even brown is likely to do with a plankton bloom of some description, or related to suspended sediments (as in this case) or other naturally arising material in the water. Instead of using this as an opportunity to become hysterical on the internet, how about celebrating the incredibly dynamic system that we can observe, living near the ocean? Drive up a mountain next to the ocean and take in the spectacle from on high. Dip your face in the water and see what it does to the viz. Take some pictures for posterity. And – if you don’t know what’s causing it – try to find and question someone who does know, like a scientist, or consult a good non-fiction book, to find out some facts.
The mouth of the Breede River is a fascinating and beautiful location. There’s a treacherous sandbar (more on that just now). There are wide, natural vistas. There are sleepy holiday villages on each side of the river mouth. There’s an additional little frisson of excitement related to the fact that bull sharks use the Breede River, and must be passing by all the time (right?!).
When Tony and I were in the area for a spring break, we explored the area. I wanted to see whether I could find the remains of SS Kadie, a steaam-assisted sailing ship that is an integral part of the history of the area. The Kadie was built in Scotland in 1859, for the specific purpose of navigating the Breede River and up and down the coast, as a trading vessel. She did venture out to sea on longer voyages, on one occasion carrying a cargo of ostriches to Mauritius. (You can read a lot more about her history, and that of the Barry family who operated her, here.)
Wreckage of the Kadie inshore and further offshore
Rusting wreckage of the Kadie
The Breede River estuary
The mouth of the Breede River (Infanta side)
Part of the Kadie in the surf zone
Remains of the Kadie
On 17 December 1865 the Kadie ran aground and sank while attempting to cross the sandbar at the mouth of the Breede River. She is easy to find, but you should visit at low tide. Take the turnoff to the river mouth from the dirt road to Infanta. It’s a small sign and easy to miss! Descend the wooden staircase onto the beach, and walk right. You will soon see pieces of the Kadie on the beach, in the shallow rockpools, and out in the surf zone. Best to go at low tide, or at least not at the peak of high tide.
