Last year television audiences were thrilled by the swashbuckling exploits of one of the saltiest sea dogs of them all, Captain Horatio Hornblower. But Ioan Gruffudd, who played the lead in Hornblower, had to work hard to wrest scenes from his co-star, a majestic frigate called The Grand Turk.

This ship was purpose-built for television and film - other credits include Channel 4‘s acclaimed dramatisation of Dava Sobel’s book Longitude. It is a faithful replica of an 18th-century man-o-war named Blandford. To recreate the ship in all its glory required the skills of some 30 specialist shipwrights, riggers and engineers, together with local craftsmen, as well as 250 cubic metres of timber and 790 sq metres of sails. She is now moored in St Katherine’s Dock in the City of London, near Tower Bridge, and open to the public until March.

The Grand Turk provides landlubbers with a vivid insight into what life was like on board a British warship at a time when Nelson was admiral of the fleet. The first thing to strike visitors is the scale of the vessel: it is enormous. At 152 feet in length, 34 feet wide, with a main mast that towers 117 feet above the deck, the ship is as long as five double-decker buses and as tall as eight piled one on top of another.

On the ship there is an exhibition illustrating what life was like in Nelson’s navy. The captain lived in solitary splendour on the main deck in a suite of cabins for day use, dining and sleeping. He not only had the best rooms, but would have had power of life and death over everyone else on board.

The crew, meanwhile, slept in squalor in shared cabins or a hammock. Although they were served three meals a day, the food was often contaminated and full of weevils and other nasties. It was washed down with a measure of grog - usually rum mixed with water.Anyone caught “on the fiddle” (stealing food or drink rations) would have been flogged or chained in leg-irons.

Life expectancy for those on a frigate was short as disease was rife. Many of those who escaped injury in battle would have succumbed to scurvy or malnutrition. Medical supplies on board were poor and of little use, so burial at sea was common.

The Blandford would have carried a variety of light arms, all carefully designed for a specific purpose. Among them were canons, swivel guns, pistols, swords, muskets and bayonets. The Grand Turk has 14 replica cannons.

School groups are catered for separately to the general public and visits must be pre-booked. Tours are given by a specialist on the Nelson era, dressed in appropriate costume.

This great ship will be touring the country this summer, visiting ports at Ipswich, Hull, Newcastle, North Shields, Dundee, Belfast, Whitehaven, Liverpool, Cardiff, Falmouth, Plymouth and Dover between May and August.

Preparations are also underway for the round-Britain voyage of the National Trust Coast Show. This will use the ship as a campaigning vessel to promote the Trust’s drive to raise pound;5 million towards the protection of coastline around the country. Costumed characters from the past, including the runaway wife of an inkeeper who has disguised herself as a man, will explain aspects of life on board. Visitors will also be encouraged to find out more about protecting the coastline.

For those who don’t manage to get on board, the ocean-going celebrities of Hornblower will soon be back for another series.

* The Grand Turk, St Katherine’s Haven, London E1 9LB. Tel: 020 7709 0788. www.turks.co.uk Open Mondays to Fridays 10am-5pm, weekends 10am-6pm.

The education officer, Paul Crooks, is based on board and handles school bookings and enquiries. Tel: 020 7709 0788.

Admission pound;4 adults, pound;2 children.

National Trust itinerary information tel: 0208 315 1111.