Isles of Scilly Underwater Centre: This is the oldest-established diving centre in the islands, based on St. Marys. It is owned and run by Jim Heslin, who found fame as one of the salvors of HMS Association (see below) and a number of other wrecks with valuable cargoes. Daily diving is from a 33ft Lochin equipped with all navigational aids, which has a large deck space and one of the easiest ladders I have ever encountered ­ a removable section in the gunwales brings you straight on to the deck. Jim has a wealth of knowledge of the wrecks and reefs and is the salvor in possession of the Association, which still has many coins awaiting discovery. A dive not to be missed. Accommodation is booked separately with one of St. Marys hotels, guest houses, self catering units or even camp sites. Parties of up to 12 divers are catered for on a weekly charter basis and bottles and weights are provided. Jim also owns the only compressor station on St. Marys, conveniently situated adjacent to Porthmellon beach and therefore providing easy access for visiting RIBS.

Island Underwater Safaris: This centre is also based on St. Marys and is operated by Mark Groves, who provides diving for small groups (up to six) and also offers try dives for the complete novice, and seal snorkelling trips for the whole family. Diving for the qualified is either from a purpose-designed 22ft catamaran (Firebrand), or from an 18ft Avon RIB. The centre is located right on the beach at Old Town Bay; perfect for try dives, and it provides an interesting beach dive, especially at night. All equipment can be supplied from a large stock (wetsuits only, though) or just bottles and weights if you travel with your own kit. Once again, accommodation is booked separately and the centre is able to advise on the best choice. Mark is also salvor in possession of HMS Firebrand (one of the Association fleet) and therefore can offer the opportunity of diving this historic wreck.

St. Martins Diving Services: The third diving centre operating within the islands is based on St. Martins and is also a BSAC School. It is owned and operated by Tim Allsop, a BSAC advanced instructor and first class diver who was previously a south-west area coach. The school offers a comprehensive range of courses, from snorkelling trips and try dive sessions through to boat handling, chartwork and up to Advanced Intructor level. The centre operates two boats, a fully equipped 35ft Offshore 105 and a 5.5m Humber RIB, and takes charter groups of up to 12 qualified divers in addition to trainees. Up to seven divers can be accommodated on a self-catering basis at the centres self-contained flat, while additional B&B, self-catering accommodation or camping is provided on the island. St. Martins also boasts the most luxurious hotel within the Scillies (the St Martins). Charters are normally on a weekly basis, although long weekends are offered in the low season. Full equipment is provided for trainees and the charter price includes the hire of cylinders for the second dive of the day (you bring your own for the first). If you are using your own RIB you may use the centres moorings on Par Beach when purchasing air on a daily basis ­ the compressor station is situated at the top of the beach. The island of St. Martins offers a much slower pace of life than even St. Marys (there are perhaps only 200 residents and 15 cars!) but it does offer total seclusion and the essentials of island life ­ two shops, a post office, and two pubs if you include the hotel bar!

Independent diving using your own RIB Each year a number of adventurous and well equipped diving clubs make the crossing from Penzance in their own RIBs to dive around the islands independently. This is not an undertaking to be considered lightly, as the journey involves crossing 34 miles of open sea, much of it exposed to the forces of the Atlantic. Only clubs with very experienced boat handlers and a full complement of navigational and safety equipment should contemplate this. There are some particularly unpredictable tides encountered en route (seven meeting between the Longships and Seven Stones Reef), and what appears to be a flat calm day in Penzance can quickly deteriorate into a rough, confused sea with enormous swells once you pass the Longships lighthouse. Once in the Scillies, be sure to seek local advice from the dive centres on tides, and safe or any restricted areas to dive. The configuration of the islands, reefs and shoals makes prediction of slack water particularly difficult, especially during periods of spring tides. When coming ashore to recharge diving cylinders with the dive centres, please use the beaches to land, rather than the main quay areas as you are bound to get in the way of local boats! A variety of accommodation is available on the islands, and, as mentioned above, safe moorings are available from the diving centre at St. Martins. Be sure to plan for flexibility for your return journey, as the weather may not be appropriate on the day of your departure. It is possible to freight your RIB on the Scillonian or the cargo vessel Gry Maritha, but this is expensive and is not always possible at weekends. The other price shock awaiting independent divers is the cost of fuel ­ £4 per gallon in the Scillies, so plan your budget carefully!