We're in the middle of the Pacific. As I write, we're rolling in a gentle swell just north of the equator on the 32,000-tonne container ship, the Hansa Rendsburg, a 175m-long Chinese-built vessel with what one of the crew described charmingly as a 'deciduous' engine - it sheds parts, apparently. Tahiti, our last port of call, is 2,000 miles behind us, and the next, Ensenada in Mexico, is another 2,000 miles ahead. In the context of 'getting away from it all', I'm not sure how much further away we could possibly get.

This is our third 'freighter cruise', having previously sailed as passengers on cargo ships from Singapore to Brisbane and from Melbourne to Napier in New Zealand as part of our round-the-world trip without flying. While we're not actually expected to swab the decks in exchange for our passage, this is a far cry from cruising. Contrasting cargo ships with cruise liners is like comparing a truck with a limousine - they both get you to your destination, but only one has a champagne fridge and leather seats. The luxurious pampering and clientele of clubby retirees are all part of the cruise liner experience and come with a price tag to match. Cargo ships are very much the 'no-frills' option.

The core business of our vessel is to shift stuff around the world. The financial benefit of our presence to the company, when fuel costs run into many thousands of pounds a day, is minuscule. We're essentially a welcome distraction, mainly because, after several months at sea the crew, if not exactly sick of the sight of each other, at least appreciate some fresh faces and new conversation.

We have a 'suite' that is pleasant and spacious enough - in a Slough Travelodge sort of way. There is also a fridge - which we've stocked with beer from the ship's store (sadly, there is no Möet). Onboard are 21 crew, a mixture of Kiwis, Ukrainians, Filipinos and Kiribatis (from a remote group of atolls in the equatorial Pacific). There's one other passenger - a retired female Canadian Mountie who 'can't stand flying' - and around 1,000 metal containers. These are stuffed with dried milk products, white goods, fruit and, in the 150 or so refrigerated 'reefer' containers, fish, meat and ice-cream. We've even got a cargo of 'low-specific' radioactive material going to Canada, which means we'll acquire a Mexican naval escort for the approach into Ensenada. That's what I call arriving in style.

With 16 days at sea, we make our own entertainment. We're studying Spanish in anticipation of our arrival in Mexico, for which I am also entertaining myself by growing a big, fat, culturally appropriate moustache. With no cinema aboard, the only 'pirates' we've seen have been in the ship's library of DVDs of dubious origin and suspect titles of the lewd, nude variety. The male crew, it must be remembered, are alone at sea for very long periods. Apparently one middle-aged woman found horizontal ways to entertain herself and most of the crew, on a one-to-one basis, during a recent Pacific crossing.

There are also opportunities for lovers of wildlife. We've seen pods of whales in the Great Barrier Reef lagoon, skittering flying fish off Tahiti, gangs of tiny petrels, and a lone majestic albatross wheeling gracefully around the ship in the Tasman Sea.

Nature is less visible in the mid-Pacific, but there's still plenty to stimulate the senses. We're fantastically remote, potentially vulnerable, yet constantly lifted and inspired by the vivid blue beauty of sea and sky: rolling cloudscapes, wildly flamboyant sunsets and star-peppered nights. We are truly at the mercy of the ocean's might, which is as profoundly humbling as it is scary.

For exercise, all ships have some form of 'gym', though this is usually a slightly optimistic description of a room with a table-tennis table, weights and an exercise bike if you're lucky. Our current vessel also has a swimming pool, which sloshes merrily with the movement of the ocean. Who needs a wave machine? It's the size of a large septic tank and filled directly with unheated seawater. As a result, it's only really fun in the tropics. Still it helps burn off the steady ingestion of food that punctuates the day.

On the gastronomic front, no two cargo ships are the same. The menus have swung from eastern European 'meat and mash' offerings to Filipino fried fish, spicy okra and plenty of rice. We crossed the Tasman on a French ship where meals were conjured up with typical Gallic culinary flair, made sweeter still by the limitless carafes of free wine. The Hansa Rendsburg is somewhere in between these extremes, though tomorrow the entire ship's company is gathering in medieval fashion to barbecue a whole suckling pig on the aft-deck, a regular mid-ocean treat.

People are a key part of the journey and are often folk you wouldn't normally speak to, let alone get to know. Sharing a ship has been enlightening, entertaining and at times socially demanding. We've learnt the hard way about Russian conversational reticence when sitting in stony silence around the dinner table. We've partied with a phalanx of friendly Filipinos over beers, and discovered a hitherto latent personal penchant for karaoke. With senior Anglophone crew members and passengers, we've wrestled (and argued) with old-school attitudes on race, religion and gender equality from perspectives unpolished with any veneer of political correctness.

Cargo ship travel is not for everyone, but in an age when any idiot can get on a plane and twang themselves to the other side of the planet, there is something uniquely satisfying about a long voyage by sea. You gain a respect for the crews who spend so many months of their lives each year half a world away from their nearest and dearest. You get to explore the mechanics of the biggest engines you'll probably ever see, hang out on the bridge and try on thick orange Neoprene immersion suits that make you resemble a cross between a Teletubby and a lobster fetishist.

Freighter cruising also gives a fascinating insight into the logistics of the way much of the world's trade is conducted - sobering when you see first-hand the scale of maritime shipping operations and the challenges involved. Cheap oriental Christmas decorations are seen in a new light when you appreciate how they've reached the UK.

A cargo ship journey is a contemplative, relaxing experience - if the weather obliges. Freed from the distractions of telephones, the internet and the modern world that permeate even the remotest holiday resorts, at sea your mind can wander, ruminate and truly escape. The tragedy is that these opportunities are in decline and capacity is limited to a few passenger cabins per ship.

Compounding this, Orwellian security and immigration measures introduced by the US in recent years have created so many headaches for shipping companies that many have simply stopped carrying passengers at all. A long, proud tradition of travel by sea is in danger of disappearing altogether. Don't miss the boat.

How to plan your own cargo voyage

Where should I start?

There's a lot of information available online from various shipping companies that offer passenger bookings, but it's not all in English and it can be confusing trying to compare what's out there yourself, so the best way to book is through a specialist agent. Among the best in the UK are Strand Travel www.strandtravel.co.uk (0207 010 9290) and The Cruise People www.members.aol.com/CruiseAZ/home.htm (0207 723 2450). Both have excellent websites, and Strand Travel's boasts an interactive map showing possible routes.

What does it cost?

Travelling by cargo ship works out more expensive than flying but your food and lodging are included in the price. The Cruise People estimate that it costs around £70 per day per person.

How does the cost compare with that of a cruise?

Cargo ships will work out cheaper, although perhaps not by as much as you might expect. P&O Cruises' American Adventure, for example, is a 30-night round trip from Southampton to Madeira, Florida, South Carolina, New York, Boston and Vigo, leaving in September, and discounted fares start at £2,599 per person, though this increases as availability decreases. The price includes meals and accommodation, but not excursions. A 28-day round trip on a cargo ship from Southampton, to New York, Virginia (US), the Netherlands, Germany and France, costs £1,775 per person, including meals, with Strand Travel. Once on board a cargo ship things are very cheap too; drinks are duty free and are not usually marked up. Unlike cruise ships, there are rarely single-supplements on cargo ships, which can make a huge difference.

Where can you go?

Options range from short journeys to the Med, to trans-Atlantic and trans-Pacific voyages or mega round-the-world trips. The longest voyage Strand Travel features is a 124-day round-the-world trip leaving from Hamburg and travelling via the Suez Canal, China, Japan, the Panama Canal and the US, which costs £7,345 per person. One of the shortest is a 10-day round trip from Goole in Humberside to Sweden, via Denmark and Germany, from £705. On most of the longer itineraries, it's usually possible to join the ship for part of the route, and it's common to fly one way, or return on another ship.

What's included?

Three meals a day plus snacks are included, as well as accommodation. You'll have to pay for drinks, cigarettes and anything else you want on board. Bed linen and towels will be changed regularly and there will be a self-service launderette for personal items. You'll need to arrange your own insurance, too.

What are the ships like?

A variety of freight ships will take passengers, but most are container ships. Accommodation is of a good standard. Facilities vary greatly but there's likely to be a lounge, with TV, DVD and CD player and a selection of films and books, shared with officers and sometimes crew. There's usually a bar and a fitness room. Cabins are generally quite spacious, tend to be on the outside of the ship, and usually have en suite facilities. Compared with the average cabin on a cruise ship, you're likely to have more space but less luxury. Generally ships will have swimming pools too, mostly outdoor.

How to plan your own cargo voyage

What's the food like?

It tends to be simple but good, often reflecting the nationality of the ship. Passengers generally have their own table, which is usually in the officers' restaurant.

How many passengers are there likely to be?

Usually just five or six, but you could be the only one. There will rarely be more than 11 because if a ship has more than 12 passengers it's legally required to have a doctor on board.

What nationality will the crew be?

The shipping companies are of all different nationalities, and the captain is usually the same nationality as the ship's owners, but the crew is likely to be a real mix, from anywhere around the world.

Are you expected to tip staff?

It is usual to tip the steward who looks after you. He'll generally clean your cabin and serve you at mealtimes.

Will I be able to see much in port?

You'll probably only have time for the most whistle-stop of tours. Most ships will spend 10-12 hours in port, but bear in mind that you could be arriving at 10pm.

Can anyone join a cargo ship?

Most companies won't accept anyone over 80. Passengers with chronic health conditions are generally not accepted.

Will I arrive on the expected date?

Departure and arrival dates are very likely to change because of weather conditions, cargo requirements, even strikes, so it's not for those with fixed schedules.

Jane Dunford