Diving Rapid Bay… These two large, side-by-side, jetties in Rapid Bay on the Fleurieu Peninsula are probably the most popular shore dive in South Australia!
It’s convenient location, 100km south of the state capital Adelaide. Together with its sheltered position and great marine life makes it hard to beat. Particularly so given the excellent chances of seeing the wonderful Australian leafy seadragon while underwater there!
With many claiming that Rapid Bay is the leafy seadragon capital of Australia… Not sure about that personally – but it is good!
The original, much bigger jetty was built back in 1940 to allow exports from the nearby limestone mine. While the new and smaller jetty was opened in 2009.
By far the best diving is on the old jetty. Particularly out at the T-Section or ‘Tee’ (a.k.a. the “Gallery” or the “Aquarium”) as it is often referred to. But the old jetty is in poor overall condition and closed to public access. So, it has to be accessed by entering the water at the end of the new jetty and then crossing over.
Straightforward overall, but not without its challenges. As getting all your gear down the new jetty is quite a haul… Then once underwater there is a fair distance to be covered. So navigation and air consumption needs to be managed carefully.
All said though, Rapid Bay truly is a great dive and well worth all the effort involved!
Diving Rapid Bay – The History…
The location is named after Colonel William Light’s 162 ton survey brig the Rapid. Light was the South Australia Colonial Surveyor General, who made his first landfall on mainland South Australia there in September 1836.
Industry came to Rapid Bay in 1938 when BHP, the big Australian, began quarrying limestone there.
The limestone was used as flux for BHP’s steel smelters at Whyalla, Newcastle and Port Kembla.
The original “BHP jetty” with its bulk loading capability entered service in 1941. Continuing through to 1988 when work was scaled down in favor of the company’s Klein Point Quarry over on the Yorke Peninsula.
The ship loading facilities were dismantled and the quarry left as a rather large hole in the ground… No real records are available on the biodiversity of the jetty prior to it closing. But it seems clear that the years since have allowed the aging pylons and overall structure to positively bloom!
But as it aged, it also became increasingly less safe, finally being closed to the public on Christmas Eve 2004. The new jetty was built by the state government, after an intense lobbying campaign, and came at a cost of $3.9m. It was formally opened to the public in 2009.
While that lobbying was strongly supported by the Scuba Diver’s Federation of South Australia (SDFSA). It would seem that the South Australian Recreational Fishing Advisory Council (SARFAC) were the driving force (“I fish and I vote”) behind it all…
At the end of the day what really mattered was that the new jetty was built. Tacit recognition by the politicians of the day that these structures are incredibly valuable!
Diving Rapid Bay – What’s Underwater?
Quite a lot is the answer to that question! While many divers and underwater photographers visit Rapid Bay to see the iconic Australian leafy seadragon, There is a much more to see there… And it’s easy to burn all your air with the leafy’s (tempting as it is) and miss out on all the other stuff!
While they lack the incredible density and almost biblical scale of those on Edithburgh jetty, across the Gulf of St Vincent, Rapid’s pylons have much to see.
The closing of the limestone mine and the cessation of industrial activity allowed those pylons to really flourish.
Just not on the same scale as Edithburgh… Principally because of the different structures on the two jetties. With Edithbugh quite low and wide, while Rapid Bay jetty is higher and narrower. At Edithburgh, colorful filter feeding ascidians and sponges dominate. But at Rapid, the hard coral Culicia is dominant.
Like wrecks, jetties create environments for marine biodiversity to thrive. Their pylons are the catalyst, providing a strong and stable platform for growth to occur.
It is incredibly tempting at Rapid to look down and forage along the seafloor. But get your buoyancy right and hover around the pylons and you will see what I mean. With at least 49 species of fish recorded on the jetty.
Overall the activity around the pylons is at its very best out on the Tee. With large schools of old wives and zebra fish adding a dynamic element to the towering structures of the six 10m square dolphins which provided the mooring points for ships being loaded.
There be Dragons…
Rapid Bay enjoys a strong reputation as one of the most reliable places to encounter the wonderful Australian leafy seadragon (Phycodurus eques). Which can start soon after you have entered the water and made your way over to the old jetty.
It is not uncommon to find a leafy hanging out around the bottom of the pylons. But the seagrass beds on either side of the jetty often have a leafy or two. So it’s worth keeping a lookout for them but don’t go too far off-piste and loose the jetty!
There are rich areas of seagrass out around the Tee which seem to be the most reliable area to find leafy’s. With the area on the outside of the eastern end particularly so! To get there, turn right when you get to the Tee, keep to the left edge of the structure and go towards the end. Remembering to monitor your air consumption, as it’s a long way back!
While I have yet to see any myself, I have seen the photographs of those who have encountered the other Australian seadragon – the less flamboyant, but almost as photogenic “weedy” (Phyllopteryx taeniolatus) seadragon at Rapid Bay!
Weedies are harder to find it seems, (certainly for me…) indicating they may be less of them than there are leafies – or that they don’t hang out where the leafies do.
Diving Rapid Bay
After gearing up in the car park comes the test of getting all your gear down the new jetty to the steps at the end and the jetty is 240m long…
One sure way of telling who the local divers are is their trolleys. While the visitors are the hot and sweaty ones!
While no doubt it is a haul, it’s a huge and very welcome improvement. From previously having to scramble in from the shore and then surface swim for 300m before the new jetty was built.
Once in the water from the stairs it’s a 50m swim over to the old jetty.
It’s a good idea to submerge and familiarize yourself with the “star dropper” posts that show the way between the two jetties. As they will be what you are looking for on the way back…
At the old jetty you turn right and start the 250m journey out to the Tee. There you have the decision of turning left or right.
It’s 100m to the end either way and unlikely that you will have enough air to do both and get back to the new jetty.
Diving Rapid Bay – Possible Hazards
Rapid Bay is not a deep dive and even right out at the Tee it’s still only about 10m, so deco is unlikely to be an issue. But with all that swimming, air consumption will probably be the limiting factor!
There are a few hazards to be aware and wary of… Starting with getting disorientated in among all those pylons, particularly so at the dog-leg on the way out to the Tee. And then around the three large square dolphins on each side of the Tee.
Basically, there are so many of the pylons it’s easy to get confused and go the wrong way. An issue that can be compounded by possible compass errors induced by all the heavy metal surrounding you…
Secondly, be conscious of the tides at Rapid Bay. You don’t want to be caught trying to get back to the new jetty in the middle of an outgoing tide!
When to Dive Rapid Bay – The Wind…
For local divers it’s a given, less so for “blow-ins”… The basic thing is that some of South Australia’s best shore dives are on opposite sides of the St. Vincent Gulf. With Rapid Bay being the #1 site on the eastern side and Edithburgh jetty the best on the western side.
The prevailing winds are principally from the south to south-east. So when it’s good at Rapid Bay it’s a really bad day at Edithburgh and vice-versa!
So, if you are planning to dive Rapid Bay you really need to check the weather forecast and understand what the wind is doing. Combine the wind info with the tide tables and you have what you need to know…
Diving Rapid Bay – Logistics
The nearest dive shop is in Adelaide, a couple of hours away… So you need to arrive at Rapid Bay with everything you need, including snacks and drinks as there is nothing at the site.
It used to be that if you were spending a couple of days diving Rapid Bay, at some point in time (depending on the number of divers/cylinders involved…) a “tank run” would have to be made to Adelaide.
But that changed when local diver Peter Corrigan opened an air filling station from his home in nearby Second Valley. A new Bauer compressor complete with storage tanks mean that refills are now quick and easy!
Peter is contactable through his Facebook page Second Valley Air Fills or by phone on 0499.229.053
There is a parking area near the jetty, but it’s long and narrow. And, because Rapid is such a popular site at the weekend, the available spots will be taken by the early birds. Meaning even further to carry all your gear.
There are several very good reasons why Rapid Bay is such a popular site… Pretty close to Adelaide, it’s a great place to see and photograph leafy seadragons, there are numerous other things to see and while it’s a straightforward dive it is also very interesting and has a nice touch of adventure too!
It gets very busy at the weekend if the wind and tides are good. Which means the car park can get a bit jammed up, but it’s such a big site there is plenty of room underwater…
Dive it during the week and you may well have it to yourself!!