AT THE narrowest point of the Bosphorus we sailed between two mighty forts then passed under the modern road bridge. As we left busy, beautiful Istanbul shimmering in the distance, all eyes were on the water to catch glimpses of dolphins.

Soon we were out on the open sea — the Black Sea. And what a contrast to the Mediterranean, which heaves with cruise ships all summer.

The deeply foreign Black Sea countries, with their difficult languages and remaining strands of Iron Curtain red tape, are a challenge to independent travellers. Taking a small cruise seemed perfect for a first visit to Ukraine, Romania and Bulgaria, so my partner Michael and I joined Hebridean Spirit’s first trip there.

Hebridean Spirit was launched only five years ago yet it has built up a loyal clientele of repeat bookers who choose Spirit for its policy of following the sun and sailing to adventurous places. From Istanbul we sailed overnight to Constanta, a historic port in Romania. Once beyond the shipping channel I was struck by the emptiness of the sea: in the far distance there was the occasional mammoth oil tanker or container ship, but otherwise it was calm water and a fabulous star show in the clear sky, unpolluted by city lights.

Because of the small number of guests on board (maximum 98) there isn’t a bewildering choice of excursions, just one in Romania (like all of them, included in the price), a whole day including monastery, lunch and a cruise down the Danube Delta.

As we drove through the countryside, rows of workers in the fields found our two shiny turquoise coaches as curious as we found them. The women in long skirts and headscarves, bent double weeding by hand, like figures from a Bruegel painting, stood up and stared. We passed horse-drawn carts laden with hay or families on Sunday outings.

At a loo stop I couldn’t resist a gorgeous bunch of 20 hand-tied deep-red peonies, proffered by a small boy for 50p, which opened gently all week in our cabin. Lunch was served by nuns at Saon monastery in their painted hall, a feast of cheeses, salad, salamis and grilled lamb all from their home farm.

After a stroll in the grounds we stepped aboard two flat-bottomed boats for an afternoon cruise down the Danube Delta. The area was teeming with birds in early summer; as our tour manager and onboard naturalist Tim told us, this corridor of land around the Black Sea is a migration superhighway, thanks to the thermals.

Birdwatching turned out to be as important as sightseeing for many guests, and they were in their element. In the Summer Palace gardens in Balcik, the first of our two stops in Bulgaria, a nightingale singing in the cypresses and a Levant sparrowhawk overhead topped off an interesting day that included a walk to the remains of the Rock Monastery of Aladza, carved in a cliff in the Middle Ages, and the orthodox cathedral in Varna. The next day we berthed overnight in the Old Town of Nessebur, allowing us to take a walking tour of its many Byzantine churches and Greek and Roman remains before the coach parties from Sunny Beach and Golden Sands resort hotels poured in.

Our shipmates were mostly retired, well-travelled, sociable Britons, some with younger companions, such as a daughter. Lone travellers are drawn into the cocktail party atmosphere in the lounge and can join tables hosted by officers for dinner. The country house party atmosphere extends past the chintzy sofas and soft furnishings, because the substantial price includes virtually everything, so you aren’t always signing for things as on a mainstream cruise. As one woman who aims to come on board every year told me: “We save up for this, and although you send off an enormous cheque months before, by the time you get on board you’ve sort of forgotten, and there are no more costs totting up.”

Our mid-price cabin was more like a hotel room, with king-size bed, roomy bathroom with a proper bath, lots of storage, a small sitting area, and satellite television. Homey touches were kettle, teabags, shortbread, and real milk in a jug in the fridge. There was even an iron and ironing board.

In Odessa, the highlights for me were going up and down the 122 Potemkin steps from the port, scene of the massacre in 1905, depicted in Eisenstein’s classic film Battleship Potemkin; the caviar in the supermarket, a tenth of the price in Harrods food hall; and an intimate recital by a string quartet in a pink and gold salon of the Literary Museum, just for our group.

We were soon to discover that it wasn’t a late-night crowd on board — most retired after coffee and petit fours in the Skye lounge of an evening. Early mornings on deck were where it was all happening. The birders were up there at the crack of dawn, making all sorts of exciting spots, guided by Tim. Many a morning I tottered up at 7.30 to find I’d missed a rare sighting. Talk over breakfast was of red-throated divers, yellow wagtails, blackcaps and, most amazing of all, red-breasted flycatchers three days running. The hardcore twitchers’ enthusiasm was infectious and when early one evening an immature red-footed falcon roosted on the mast, way off course for Siberia, we all put down our books and needlepoint and borrowed binoculars.

One charming and quirky moment was when two exuberant Ukrainian waiters paraded a haggis around the dining room to the tune of taped bagpipes at the captain’s farewell gala dinner.

Our last night was back in Istanbul where we berthed right in the centre, near the Galeta Bridge, for a day and a half’s sightseeing.

The only small disappointment for me was that the distances covered on our voyage of 853 nautical miles meant that we sailed mostly at night and so saw little of the coast. But for a taste of four distinct and fascinating countries, this intimate cruise managed a perfect balance in one relaxing week.

Need to know

Hebridean International Cruises (01756 704704, www.hebridean.co.uk) has a 13-night Pearls of the Black Sea cruise from Istanbul to Constanta leaving on August 8 next year from £5,380pp. Ports of call are Sinop and Trabzon in Turkey, Sochi in the Russian Federation, and Kerch, Sebastopol and Odessa in Ukraine.

The seven-night Gateway to the East from Constanta to Kusadasi calling at Balchik, Istanbul, Canakkale and Dikili is from £3,095pp and leaves on August 21.

Prices include private charter flight from Stansted, all meals, drinks, excursions and tips.

More Black Sea cruises: Costa (020-7940 5398, www.costacruises.co.uk) has 11-night fly-cruises on Costa Europa departing Savona on May 28, July 9 and August 20, from £789pp.

Fred. Olsen (01473 742424, www.fredolsencruises.co.uk) has a 28-day cruise from Dover departing on September 21 next year aboard Boudicca, from £3,117pp.

Thomson (0870 5502562, www.thomson.co.uk) has seven-night fly-cruises departing Thessaloniki from May to October aboard Calypso, from £599pp.

Times recommends

• Delay your journeys to Christmas Day, drivers told
• Where to ski, month-by-month, this season
• The Times Christmas Walks: 20 winter rambles