A murky surface layer and strong currents is what I had been forewarned about the Atlantic side of Tobago, then advised once below the surface layer visibility improves.
Today at Bookends there is no murky surface layer, just stunning visibility and only a gentle current. This was my first dive at Bookends and to be honest it didn't even occur to me that we had missed the tarpon bowl until after the dive. I was having too good a time on the reef. All the usual hard corals are there in profusion, but the real plus are the sponges.
My hosts for this trip are the Hilton hotel and the attached dive centre World of Watersports at the south end of Tobago. Little Tobago would be a long way to travel by boat, so Rae De Beer from World of Watersports drives us by car to Speyside where he has an arrangement with Rene, a local boatman.
The road winds along the coast, never quite un-made and never quite single track. Typically Caribbean small towns and villages on the way have familiar names. The capital is Scarborough, then we pass Hillsborough, Goodwoood, Pembroke, Richmond and Roxborough, where Rae informs me the island's recompression chamber is located. The journey takes just over an hour.
A few days later I am back at Speyside and again diving Bookends, this time with Rikky Knowles, Rae's business partner at World of Watersports. There is still some surface current where waves wash over the protruding rocks, but underwater it is almost slack. I head straight for the tarpon bowl.
Even then I don't spot them immediately. I was watching the dense clouds of tiny white bubbles surging above me as waves from the Atlantic crashed over the rocks. A contrasting dark cloud of tiny silversides was pulsing in and out, maintaining an almost solid but living margin against the white foam.
Then a clear ring forms in the shoal, transforming into a rounded cut between the silversides and the foam. A procession of four or five tarpon cruise through. Huge silvery fish with a lantern jaw, almost prehistoric in design.
The reef below me is without doubt an excellent dive, but the clouds of tiny white bubbles, silversides and tarpon are both excellent and different. Striving to balance this complex scenario, it takes me another 20 minutes to finish the film. I fire my last shot on a shoal of jacks that streams through, adding yet another moving element to the equation, and wish for more than 36 shots on a roll.
Another significant dive at the Speyside end of the island is Kelliston Drain, often referred to simply as Brain Coral after a huge brain coral, thought to be the largest in the Caribbean.
The dive starts a fair way up current from the brain coral, with the standard plan being to drift along a frustratingly nice sloping reef before meeting the brain coral towards the end of the dive. Like bookends the current is unusually light and we end up swimming to make progress.
I say frustratingly nice because I am constantly faced with the dilemma of shooting film now on the reef, or saving it for the brain coral I am expecting at the end of the dive. As with most dives on Tobago there is a particularly strong contingent of angel fish, presumably prevalent in these waters because they like to eat sponges.
I think I may have confessed previously that brain corals are a favourite of mine. I like the clean domed outline and intricate maze of grooves between the polyps.
My reward is certainly the largest brain coral I have ever seen, with the added bonus of a French angelfish that has stopped by to be cleaned by the numerous gobies and small wrasse which reside on this well marked cleaning station.
Less spectacular but still enjoyable dive sites are on the more sheltered Caribbean side of Tobago, departing from the pier at Pigeon Point at the southwest end of the island.
Divers meet at the spotless modern dive centre, the sort of building you would expect to be attached to a top hotel, and then travel across to Pigeon Point by minibus or pickup. On the way we stop to collect divers staying at other locations and fresh fruit for snacking between dives. The journey takes about 15 minutes overall.
Continuing the theme of familiar names, I dive a reef at Arnos Vale, a name shared with a street only a short distance from my home in Bristol. The inshore reef here is a popular snorkelling site. Further out it breaks up into a sandy seabed with shallow patches of reef. Ideal for fish photography because the patches concentrate and localise the fish.
Further up the west coast, an early morning start is needed to get to The Sisters, a group of rocks a good 45 minutes away.
On the way we pass the small town of Plymouth and bays reflect a buccaneering history with names like Culloden and Mount Irvine. Further north are the more explicitly named Bloody bay and Man O'War bay.
I am a little disappointed with the dive. For something we had gone to such effort to see it is all a bit average. Not that there is anything wrong with average, average reef in the Caribbean is still a good dive, but I was expecting fantastic.
Maybe it was the unusual lack of current again. We had dropped in to the north of the rocks intending to drift the whole length of the reef, but had only progressed as far as halfway along the reef by the time we surfaced, and it was the second half of the dive that was best. Large rocky pinnacles with steep walls and canyons in between.
I suppose the corollary would have been equally awkward and much more difficult for our boatman. If we had dropped in halfway along the reef in a ripping current we would have been swept off and dispersed into blue water in the first few minutes.
Also on the west coast, the must-see wreck in Tobago is the Maverick, once a car ferry running between Trinidad and Tobago. Pensioned off when replaced by a larger ship, it was cleaned up and sunk as an artificial reef in 1997.
Descending the line the visibility isn't perfect, but it is plenty good enough. I am only a few metres down before I can pick out the rough outline of the superstructure from the general haze. At the end of the line the stern A frame mast stands out better against a light blue background.
I continue downwards past the square stern to the seabed. The propellers are removed, but the two shafts and rudders are beautifully adorned with soft corals in a slight scour beneath the hull. Indication that currents can be stronger than the slack water I am diving in.
To be pedantic the Caribbean does not have true soft corals, but octocorals which form fans, whips and other shapes in-between. It is just that soft corals is the term in common use, so I will stick with it.
The array of fans on the bow is even more impressive than those on the stern. It's amazing that such a dense collection has managed to become established and grow to such size in just 4½ years. They must grow at a much faster rate than similar UK species, where fans this size would be getting on for 100 years old.
Having dipped down to the seabed again I am now very conscious of balancing my remaining air against decompression requirements. I make a brief excursion into the cabin on the main deck before ascending to the superstructure and wheelhouse. The kind of location where you might expect shoals of glass fish, but not today.