Porthkerris reef occupies a fond spot in my diving memories. Save for a couple of dives in a quarry, this is where I made my first open water dive. Shivering in the last week of March I survived about 30 minutes dressed in a Cousteau classic wetsuit and repeated the dive several times over the week.
On the following year's trip I was warm in a drysuit and helped take then next batch of novice divers in, and the year after that I organised the trip. Without counting log book pages in detail, I would guess I have made over 200 dives on Porthkerris reef and I still enjoy it every now and then. I am sure there are local divers who have made many more dives there, just dropping in for a quick dip after work one or two evenings per week.
So what is so special about this dive site? Is it magic or is it just me getting nostalgic?
Under most conditions Porthkerris is actually quite an easy dive. You just drive up, carry your gear down a stone slope, put it on, take a compass bearing on the rock at the south end of the reef, slop into the water and swim out along the seabed.
The only difficult part is descending the stone slope, especially if it is wet and slippery. The dive centre has fitted a rope handrail to help you with this, but somewhat perversely I used to find it easier before the handrail was there. There is a natural zigzag route down the rocks, but the handrail goes straight down making it impossible to follow the easier zigzag route.
Underwater the shingle beach shelves down to rows of small rocks and kelp beneath the low water mark. Continuing out you come to a shingle bowl just inside the reef, a popular spot for gathering a training group round and doing all those static exercises at the start of a lesson.
To get to the seaward side of the reef there is a choice of going round the south end of the rock, or through a gully that separates it from the rest of the reef. Either way there are small sections of wall with anemones, hydroids, tunicates and dead men's fingers.
Heading north along the seaward side, the first cut back into the reef is an obvious shingle floored gully that goes a fair way in and ends in a cauldron with almost vertical walls. Vertical cracks in the walls are well worth investigating, as in addition to the usual shrimps and blennies there are often conger eels to be found in the larger cracks.
A little further on another cut starts a few metres up the slope of the reef and ends sooner and shallower in rocky bowl that seems to collect dead kelp.
Continuing north, it is definitely worth staying a few metres up the reef rather than following the seabed. The next highlight is a large circular scour hole, followed by a 45 degree overhanging rock face. Sheltered from sunlight and protected from scouring, this face has some of the best anemones and dead men's fingers on the reef.
After this a wide wedge cut into the reef ends in a short gully with a boulder across its entrance to make a chimney cave. The hole in the roof is easy enough to fit through with a single cylinder and pony on, but I wouldn't like to attempt it with a twin set or rebreather.
The reef then turns out to sea where there is another steep wall covered in small jewel anemones. This is the deepest point on the reef with the seabed at 18 metres at high tide.
To complete the dive there is a choice of retracing your path back round the south end of the reef, or below mid-tide of completing the circuit and exiting at the small beach under the MOD station.