Expand here for a dive site description
Diving Dobroyd Head from shore
If you enter the water at Forty Basket beach and you turn right you will see that the coastline is quite boring, kelp in the first 4 meters and then sand, yet sometimes sand hosts some interesting species such as a very small Hammer Octopus (the size of a bluelined octopus) I saw there in September 2020. You may also come across seahorses near the beach, apparently a colony has been relocated here some time ago when a bath net was removed.
A better option is to bypass that section of the coast by walking from the car in Beatty st down to Forty Basket and then take the coastal path till Reef Beach for 700 m, which is mostly flat. I know, it's a long way with tanks and gear, I hear you! I did it in October 2020 in a drysuit and carrying a heavy camera.
Once you get to the pristine Reef Beach you will be rewarded by its beauty, especially once you look back into the bay at the end of the dive. I did a night dive there and I still have a vivid memory of the lights from Manly and Quarantine Station reflected on the clam surface of the water in the silence of the night.
Once you get in the water at Reef Beach, go right. The underwater landscape isn't very interesting at the beginning, bare boulders with just sea urchins and sporadic sea tulips, not much fish around. It gets significantly better as you head South and the sandline goes down to 10-12 meters, here the boulders are covered by vegetation and sponges of every colour. Many stonefish amid them, a moray eel and a solitary female Port Jackson enjoying a relaxing night without being chased by males (10/2020).
Be prepared to be overwhelmed by the noise of the Manly ferry passing pretty close at full power. Many abandoned anchors trapped in the cracks between the boulders, I counted 4.
All in all it would be an interesting site to revisit and explore a bit further South as air allows and with better visibility. Tonight it was really poor and with a visual range of 3 meters it's hard to stay relaxed.
The wreck off Forty Basket beach
If you want to practice a bit of exploration you could go to see the speedboat wreck positioned off the coast between Forty Basket beach and Reef beach. It can be a bit tricky as it's 200 m away from the coast so underwater compass navigation has little chances, especially if you find 2 m visibility as I did in October 2020. I often find that as you approach the lowest portion of the harbour, there is a layer of heavier than water particles a few mether thick sitting there.
Also to be considered the risk of boating during the day if you plan to surface swim. My solution was to do a night dive and use the submersible GPS described here to surface swim to the exact wreck location found on Navionics maps., 420 metres from Forty Basket beach.
Once on top of the wreck, which I could not see as the visibility was extremely low, I descended to the bottom at 12 m. The visibility was so bad that I literally hit the floor as it appeared. As I started to move around I found the wreck 3 meters away from where I landed. I then moved 2 meters away from it to avoid stirring the sediment while I was setting the strobes and camera and as I looked up the wreck was gone. It took 10 minutes to find it again swimming in search patterns!
The wreck itself is a 6 m speedboat, not exactly the Titanic but it was more a test to see if the solution worked and if was easy to swim following the indications. It worked really well and I suggest it whenever you are planning to start your immersion at specific location. I reckon it would also be good for freedivers wanting to find something of known coordinates. Not much sea life around in the desolated sandy bottom, apart for a very cute 25 cm Port Jackson shark.