A Scottish diver has completed a 30-year mission to visit and chart the greatest shipwrecks round Scotland's coast, including a steamship packed with beer that was once owned by Glasgow's great art collector Sir William Burrell.

Rod Macdonald, 53, visited the SS Wallachia, which is packed with thousands of bottles of McEwan's Export and sank on the Clyde in 1895, as part of his mission to get a snapshot of the greatest wrecks in the UK.

Mr Macdonald, from Stonehaven in Aberdeenshire, dived to more than 25 wrecks in Scotland, including some that have never been visited before. He is also the first diver to chart all of the wrecks in Scapa Flow in Orkney.

On his visit to the Wallachia, Mr Macdonald saw for himself the thousands of bottles of beer that are still packed into the vessel's hold. "The wreck still smells of beer and it's a brilliant dive," said Mr Macdonald.

"Burrell made his money by commissioning ships when the market was poor on the basis that everything's cyclical and once the ships were finished, maybe the market would have picked up. He was a great man."

Sir William, most famous now for the Burrell Collection in Pollok Park in Glasgow, bought the Wallachia to ship goods to the British Empire. The beer, along with whisky, coal, books and other goods, was due to be taken to the West Indies, but after setting off from Glasgow on September 29 1895, the vessel collided with a Norwegian steamship in poor conditions and sank within 25 minutes. Some divers have tried to bring the bottles of beer to the surface, but the change of pressure meant the corks popped out.

Mr Macdonald, who has charted the dive in his new book Great British Shipwrecks, said diving to the Wallachia and other ships like her was an extraordinary experience.

"As you go down, first of all, your eyes are adjusting – it's quite dark and moody," he said. "As you look over the deck, it's pitch black – some people don't like the experience but after 20 minutes your night vision has kicked in and you can make our large sections of the vessel. You can see on average 30 to 50ft. Some days, you get incredible, crystal clear visibility. Part of the thrill is going 300ft down into the blackness and not knowing what you're going to see."

In all, there are about 18,000 shipwrecks around Scotland – most domestic, but many military – and Mr Macdonald says part of the buzz for him is trying to be the first to reach some of those wrecks.

"It's an adventure," he said. "It's the pinnacle of diving to be the first person down on a uncharted, new, virgin shipwreck. You think: what is it? Is it a U-boat? Is it a freighter?"

One of the wrecks Mr Macdonald was the first to reach was the SS Creemuir off the Aberdeenshire coast. The vessel was sunk during the Second World War by a German boat that was allowed into Scottish waters after cracking British signals and imitating them.

Mr Macdonald has also visited the wreck of the Akka, which set off for Glasgow from Sweden in April 1956 but sank in the Firth of Clyde after hitting the Gantock Rocks near Dunoon. The wreck is still relatively intact and divers can swim through corridors and cabins. "She's the biggest diveable wreck in the Clyde and is still in a pretty good state," said Mr Macdonald.

Mr Macdonald has become the first diver to chart the seven remaining wrecks in Scapa Flow, where the German fleet was scuttled at the end of the First World War, sinking 74 vessels.

"When you see them first of all, they're piles of junk and you never think you'll have a connection with that piece of metal, but then you hear about survivors of the wrecks and suddenly the pile of metal acquires a form and a life," he said.

"There are 12 men who've walked on the moon, but some of the places we divers go, nobody has been."