If you feel a sharp tug on your fins, it usually means one of a few things: your buddy is trying to tell you that you are going the wrong way, you are going too fast or you are just in the way.
When you dive around Carreg Y Trai, off the Lleyn Peninsula in North Wales, it is also likely to mean that you are just not playing hard enough with the seals.
The small island of Carreg Y Trai is also known as the half-tide island as it is submerged for half the tidal range. Under the waves, a colony of about 40 seals waits for the tide to lower so that they can continue the serious business of lying around doing nothing.
Underwater, the seals are far more energetic. The juveniles, mostly the females, become inquisitive of visiting divers. They seem to delight in tugging at fins and showing off their swimming skills - they swim towards you at high speed, only to veer sharply away at the last minute.
As with most diving experiences, nothing is guaranteed - sometimes they just do not feel like playing. If that is the case, then the dive can be saved by the wreck of the slate carrier Timbo, lying against the rocks in about 12m. Most of the wreckage is broken up, but the boiler is intact and is home to shoaling pollack.
This area of the Lleyn Peninsula is better known for the holiday village of Abersoch, where every summer the beaches and waters come alive with the bright sails of yachts, sailing dinghies and windsurfers.
The areas most prominent landmarks are Carreg Y Trais neighbours, the St Tudwals Islands (East and West). Although I would not describe the diving around these two islands as spectacular, they are useful novice diver sites. In depths of 10-15m on a rocky bottom I have seen dogfish, crabs, lobsters and all the usual residents found in kelp beds.
Further along the coast, the diving becomes a little more serious. At the tip of the Lleyn Peninsula is the island of Bardsey. Hundreds of years ago, pilgrims made the sometimes perilous journey to the monastery that once existed on this island.
Divers will find the waters equally dangerous if they do not adequately prepare for the strong currents that pass this island. These currents bring life to the area; the steep drop-offs on the east side of the island are covered in colourful invertebrate life.
Depths of 50m plus can be found in this area and unless the dive is well planned can be accidentally found courtesy of strong down-currents. On the west side of the island, a series of ledges drops down to 30m. Seals may be sighted around here, although they tend not to be as playful as those found off Abersoch.
The south-western tip of the island is made up of deep gullies, large boulders and overhangs that drop down to similar depths.
In the channel that separates Bardsey from the mainland is a small rock called Carreg Ddu. This pinnacle has a steep drop-off down to 40m that is covered in jewel anemones. Once again, this is a site for experienced divers only.

When perfect conditions allow, a treat for any diver is Caswenan Rock, a submerged pinnacle to the south-west of Bardsey Island. Starting in 23m and dropping to 50m, there are actually two tips to this pinnacle. Fish regularly shoal in the area; and within the rocky ledges enormous crabs, lobsters and the occasional crawfish take advantage of the fact that they are rarely visited or fished for.
On the north coast of the peninsula lies the town of Trefor, which offers an interesting night dive around its pier. The pillars support all kinds of life at depths of no more than 10m. The pier is a popular fishing location, but divers need to be aware of the risk of fishing-line entanglement.
One of the attractive features of diving around the Lleyn Peninsula is that you are always guaranteed a dive. When the weather makes it impossible to dive the ocean, you can head for Dorothea Quarry. This site could be the Stoney Cove of the north if it had the facilities. However, many divers prefer it just as it is, unspoilt and without fees!
There is a makeshift parking area at the top of a short path leading to the water. There is not much room for kitting-up at the base of the path, so a little diver etiquette is required, particularly when the site is busy.
Once in the water, there are drop-offs, pinnacles, the compulsory quarry sunken vehicle and an old crane. A few tunnels exist, the most popular being the one that starts at the old blockhouse at a depth of about 20m, only a short swim from the entry point.
The quarry covers several acres and in places plunges to depths that exceed normal sport diving limits.
Over the years, there have been a few incidents in the quarry. Although it is fresh, enclosed water with average visibility of around 10m, it can be cold and deep. There are no emergency facilities near the quarry, and no phone nearby.
For years there have been rumours of Dorothea being closed down, and not long ago the entrances were blocked off to prevent a group of travellers setting up camp there.
The land is privately owned, but to my knowledge the owner has never made divers unwelcome. No trespassing signs are absent at the site which, apart from the above occasion, has always remained open to the public.
At the time of writing, the council is considering an application to develop the site as an outdoor pursuits centre. However, a local source tells me that this is likely to come to nothing. So for now Dorothea will remain as it has always been - an excellent place to train and a great bad-weather retreat.

Our weekend breaks...



GETTING THERE: From north, excellent road access via upgraded A55; from south or Midlands, head towards Porthmadog.
ACCOMMODATION: Abersoch area is a popular seaside resort. In summer, accommodation can be difficult to find, although there are plenty of places to stay in quieter periods.
DIVING: Full diving services available only through Lleyn Marine Charters, 01758 740899, run by Alan Grey, a BSAC Advanced Instructor who has been diving the area for 10 years. His 6.2m stern-drive RIB (air, oxygen and first-aid equipment carried on board) accommodates up to six divers. Bed and breakfast in en-suite rooms plus two dives a day costs£38 per person, based on six divers.
CHARTER BOATS: Available as a package from LLeyn Marine Charters.
LAUNCHING: For St Tudwals Islands - excellent concrete launching-slip halfway down main beach at Abersoch. Entrance is just outside village and is signposted. The slip gets very busy in summer, launch fee payable at beach car park. For Bardsey Island, launch at Aberdaron beach - no slip, just small side road leading on to beach. Sand can get very soft, especially in summer. A local tractor-owner offers launch facilities in summer or by arrangement at any other time - contact James on 01758 760496.
Air is available at Tyn Rhos Diving (01758 740712) in Mynytho.
For Dorothea Quarry, nearest air source is at Trefor, 10 miles away (Plas Yr Eifl Hotel, 01286 660781). Nitrox should be available soon, and bed and breakfast accommodation with en-suite facilities costs£25 per person; shared downstairs bunkhouse£10 per person.
WHO WILL ENJOY THE DIVING: Novice divers around St Tudwals Islands, more advanced diving around Bardsey Island.
FOR NON-DIVERS: An ideal area for families, with clean beaches and excellent bathing, and the ever-popular trips to see the seals.
FURTHER DETAILS: Abersoch Tourist Information Centre, 01758 712929.
PROS: Healthy mix of scenic and wreck dives. Coastline littered with wrecks still awaiting discovery. Always somewhere to dive, whatever the weather.
CONS: Strong tides around Bardsey Island and advice from local divers is a must for those new to the area. In summer Abersoch is extremely busy.