IN SOME PARTS OF THE WORLD, THEY JUST WORK IN A DIFFERENT WAY. Its still a bit windy from the storms overnight, but to my mind things look good as I get to the Odyssey Dive Centre next to the hotel. Kit is being assembled and a video camera put into a housing.
     Then James, Neilsons on-site dive instructor, breaks the bad news. Dive-centre owners Goran and Zoran are making a training video today, so wont be running any diving for us.
     The good news is that we can borrow bottles and weights. James has a word with the sailing and windsurfing team, and soon we have a ride organised in one of their small cover boats to an island just across the bay.
     With the rough sea conditions we cant go much further in such a small boat, but at least were going somewhere. Its one of their open-water training sites. I think I hear them refer to it as Donkey, but I put that down to a trick of the ears.
     We swim along a series of shallow ledges that run below the shore line, 3-7m deep. I see nudibranchs, a lot of the small wrasse that seem to be everywhere in the Mediterranean, scorpionfish, sponges and lots of sea grass.
     Towards the end, James points out a pile of bones. It dawns on me that this dive site really is called Donkey, and this is the reason, though how the unfortunate animal got there remains a mystery.
     Back on the beach, James asks me what I thought of it. Im sure I took some worthwhile photographs, but I have to say that the dive itself isnt that exciting, as James had originally said. Its no more than a good shallow training site.
     I explain my BLT sandwich theory of diving destinations. A BLT sandwich has certain necessary ingredients. The bread - I already have that, the trip to Croatia hosted by Neilson. The bacon - the real meat of the sandwich. Tomato - that adds a bit of flavour, vitamins and secondary interest. And finally (and out of sequence) the lettuce - adding bulk, a bit of texture and some more vitamins.
     Together they make a balanced sandwich. Individually a bacon sandwich is usually appreciated, a tomato sandwich sometimes works, but who would eat a lettuce sandwich
     In the great BLT scheme of things, Donkey is a lettuce dive.

The dive centre is busy all day with the video, so for an afternoon dive we wait for the dinghy sailing to finish and borrow one of the cover boats again, complete with crew and driver.
     Black Rock is straight out of the eastern entrance to the bay, a small islet poking up from the typically deep blue Mediterranean water. The wall itself is fairly bland - just short, calcifying algae on the limestone. The interest lies in what we can find living in the nooks and crannies.
     A movement by a razor shell catches my attention. An octopus has set up home inside it. James watches me with a bewildered expression as I spend a good 10 minutes playing with camera and strobe angles, covering just about every possibility short of prising the shell apart.
     After the dive he suggests: Another piece of lettuce What was so interesting about that razor shell
     Not lettuce, I reply, An octopus counts as a small piece of streaky bacon, though not enough to fill a sandwich.
     We make it back just in time to shower and clean up for the welcome party, with its lethal punch and nibbles. I sample each and settle on one with a strong rum flavour. At least that way I have some awareness of how much I am drinking, and I want to stay capable of diving in the morning.
     We do better on timing than the members of the mountain-biking group, who are still wearing their mud-sprayed Lycra shorts - not that their clothing inhibits them from knocking back the punch.
     Odysseys video work is over and we head out to dive Camel Island on its traditional wooden boat. No, there arent any bones. The outline just looks a bit like a camel.
     We begin steep and deep on a wall, then turn round the end of the island into the shallows and a wreck from the 4h century; a large pile of broken amphorae and some ballast stones. I have never dived on a wreck of this advanced age before.

Later in the afternoon, the sea has calmed and we are back on one of the sailing teams cover boats to Maslinovac Reef, part of the same geological line as Camel Island, but further south and not quite breaking the surface.
     Its a classic feature of the Dalmatian coast, ranges of mountains and valleys running parallel to the shore which have since become flooded, leaving long, thin, mountainous islands, steep shorelines and many rocks rising out of nowhere to just short of the surface to catch unwary shipping. The geology is so textbook that the term Dalmatian Coastline now describes any such coastal feature throughout the world.
     The dive is another steep, deep wall, but this time with a lot more fish - clouds of tiny black damselfish, salpe and bream. Above us some barracuda keep their distance, while from the blue we are buzzed by a small shoal of amberjacks.
     On top of the reef is another ancient wreck, marked by a few amphorae and a much larger pile of bricks which would have been a combined cargo and ballast.
     For the past two days, James has been telling me that we need to get round to the south side of the island for the best diving. Finally the wind drops and we are off to Zavrti in the dive centres boat, to find walls and caves.
     The dive starts with a shallow cave under the cliffs, a triangular opening that flattens almost into a letterbox, with a chimney hole at the back to daylight above.
     Apparently it is the wet part of a larger complex of caves that pepper the cliffs above us.
     The dive continues out across the shallows and down a wall. On a big scale the wall life itself is still uninspiring. The interesting part is beneath the enormous boulders banked further down. Its where all the larger fish hang out, with lobsters and some much more colourful sponges covering the shaded underside of the rocks.

The diving is getting better all the time. It started with lettuce and were now up to a fair-sized rasher of streaky.
     I am just getting into things on Mljet island when it is time to move on. Neilson is moving its entire activity-holiday operation further north from Pomena on Mljet to Lumbarda on the island of Korcula for the 2004 season, mainly because it will be a better base for its yacht flotilla holidays.
     So rather than limit myself to this seasons diving, James and I travel north to check out next seasons dive centre and diving. After all, it will be more relevant to any of you considering a visit.
     The MM-Sub Dive Centre in Lumbarda operates to a tight schedule on a large glass-reinforced plastics hardboat with a cabin. It wouldnt look out of place in the UK. Weather permitting, the timetable begins at 9am for a 9.30 departure, then 2pm for a 2.30 departure.

First dive is the Military Base. I jump in, and immediately spot an octopus. Then its down the slope of a cut in the wall, counting the lobsters in the cracks and beneath overhangs.
     Lobsters here are spiny lobsters, more like crawfish than our own clawed variety. I lose count somewhere between 15 and 20. Another rasher of streaky.
     Captain Miljenko confesses that he doesnt think the afternoons dive is really what Im looking for. I fit a macro lens and have no trouble filling a film with nudibranchs and other small stuff. In the great BLT scheme of things, its mayonnaise. Some divers would love it and others would hate it.
     For an evening out, we catch the bus into the old town of Korcula. Its a classic walled medieval town on a rocky peninsula, with tall stone buildings, narrow stepped alleys and wider squares all surrounded by the old city wall. Its just the right size for browsing of an evening before stopping for a pizza and some beer at one of the many pavement restaurants.
     We could have done with borrowing bikes from Neilsons land-activity team, because come time to go home, finding an empty taxi proves impossible. In the end, we set off on foot and walk for an hour before we manage to flag a taxi down at a crossroads. Its the sort of thing that will no doubt be sorted out by the time Neilsons operation relocates to the island. The reps are well-enough organised to lay on an excursion bus.
     Its early autumn, and the weather is becoming unpredictable. The Bora, a cold wind from Siberia, is cutting across eastern Europe to the Adriatic. On and off, it has been constraining diving all week. Overnight, it hits with a vengeance.
     Miljenko has some interesting diving planned, caves at 35m, then deep narrow canyons at 30m. We have also talked him into an afternoon visit to a well-broken wreck of a steamship that he suggested would be better as a night dive.
     Gales from the east make it impossible to get out of harbour. Bacon is off the menu for the day. So is lettuce and tomato.

All week I have been hearing tales of the S57, a German torpedo boat from World War Two.
     The S57 was part of the escort force for a German coastal convoy bringing supplies to Dubrovnik. The convoy was ambushed off Korcula by allied torpedo boats, all ships being sunk apart from the S57 and a tanker.
     The tanker made it along the coast to Dubrovnik, but the S57 was damaged badly and later scuttled off the mainland near Zuljana to prevent the boat falling into allied hands.
     Its the classic dive of the area. Everyone talks about it and the dive centres all have posters of it in their windows, Miljenko has a model of it, but being 12 miles away, it is at the limit of sensible boat trips from either Mljet or Korcula. As James says, its the sort of dive that cries out to be organised as an excursion for experienced divers.
     Miljenko has no trouble setting it up for us. A phone call to the Zuljana Tauchbasis, then another phone call to a friend who runs a taxi, and everything is in place. No problem, Croatian Diving Mafia, he beams at us as he puts down the phone.
     Captain Dragans boat is a big converted trawler. It chugs for 30 minutes close in to the coast, well sheltered from the Bora blowing off the mountains. Dragan speaks a bit of English, but conversation is easier in German, with one of the 15 or so German divers acting as translator.
     Dragan offers that I should go in first. I explain that I would prefer to go in last, giving the others a good half-hour start to see the wreck and run out of bottom time. The tactic works, and James and I have the wreck to ourselves.

The S57 rests on a sloping seabed, the bow at 20m and the propellers at 35m. Construction was a steel frame with plywood hull, now rotted to leave the skeleton of the S-boat.
     Torpedo tubes are faired into either side of the bow, complete with live torpedoes. Behind these, reload torpedoes are stored on the deck. The detail is immaculate, down to the compressed-air plumbing for launching and the cables and tiny winches of the reload mechanism.
     All the metalwork is covered with orange and purple encrusting sponges. Visibility is the usual stunning - we can see from one end to the other.
     On the aft deck, the twin anti-aircraft gun still swings on its mount. Below, a pair of diesel engines fill the hull.
     James is catching on to my system of judging dives. As soon as we surface, he remarks that on the great BLT scheme of things, this is bacon.
     I can only agree. The S57 is a thick, juicy slice of gammon.
     The more discerning connoisseurs of BLT sandwiches will have noticed that I havent mentioned tomato. Ive been saving the tomato for last.
     At the Military Base off Korcula, the highlight of the dive is a live WW2 sea mine, complete with horn fuses and brass serial number plaque, just resting on a shelf on the reef.