It is still uncertain what caused the explosion on board HMS Princess Irene and the subsequent loss of 352 lives.

As the Island remembers the 100th anniversary of the wartime disaster, we look back on that fateful day.

The explosion happened in Saltpan Reach, 400 yards off Port Victoria on the Isle of Grain.

The Princess Irene was a passenger liner converted to a minelayer.

Some 352 men – including 78 workers from Chatham and Sheerness dockyards – died, along with people on shore.

The ship had been taking on mines brought down in barges from Upnor or round from Woolwich.

On Thursday, May 27 1915, the mines were being activated ready for her third minelaying operation.

The dockyard men were there to strengthen the improvised gun decks.

At 11.12am there was a tremendous explosion, and then another. A dense cloud of vapour and smoke shot two miles into the air.

An officer on a ship 100 yards away said the noise was the most extraordinary experience of his life. The Princess Irene seemed to be hurled into the air a mile high in 10,000 fragments. He could distinctly make out the forms of men amid the flying wreckage.

The end of the vessel was appalling, sudden and complete, he said. “She did not go down she simply went up and distributed her remains over an area of a score of miles.

Wreckage from the Princess Irene blast fell up to 20 miles away. A nine-year-old girl on the Isle of Grain was struck and killed by a piece of metal while people in Sittingbourne were injured by falling debris.

From his position on the stern of HMS Actaeon, 500 yards away, Lt James Manners said he was slightly dazed for a few seconds after the explosion. But on looking to where the Princess Irene had been he could see nothing but a mass of flames and white gas.

He said he saw two mines burst 40ft up in the air.

Two dockyard employees had left the minelayer in a government pinnace just minutes before the explosion and were lying on cushions in the cabin. One of them, George Kilpatrick, said they had gone out to see what had happened but were compelled to seek refuge from the debris which was falling all about them.

When they were able to emerge once again from the cabin there was no sign of the Princess Irene, which they had been working just a short while before.

A section of steel from the ship weighing an estimated 10 tons was found on the Isle of Grain.

At the end of an inquest, Captain James Fairie, a member of the Board of Enquiry that had been set up, said it had been concluded that the ship exploded through some unidentified cause. But there was no evidence of blame. The coroner Mr CB Harris said the ship had carried the mystery of her fate with her.

But subsequent investigations concluded a number of problems with the mechanism by which the mines were primed for action. There were also weaknesses in working procedures.

Either a dental appointment or a last-minute transfer saved a Royal Navy signalman from being killed.

John Jeffrey Sutton was born in Brighton in 1894 and enlisted at Portsmouth in June 1912.

He gained petty officer certification in June 1913 and in March 1915 he was transferred to serve on the Princess Irene.

He was only 18 and by a fortunate turn of events he was not on the vessel at the time of the explosion.

His granddaughter, Carolyn Little, says according to a book written by John Hendry he had gone to the dentist that morning.

However, she has also read, after delving into his naval records, he was transferred to another ship at 9am on May 27, just over two hours before the unexpected tragedy.

Her grandfather was one of three men who avoided death that day.

There are accounts that one of them had gone ashore to post a letter while the other may have been absent from work.

Mrs Little, who has flown over from Australia to attend the service today, said: “He was obviously lucky.”

When asked if her grandfather ever brought up his narrow escape, the 62-year-old said: “All he said was out of all the ships he was on, the Princess Irene was blown up.

“He didn’t tell us why he was so lucky and what had happened. He still has a son and daughter alive and they cannot recall any other details.

“It was significant to him because he called his first born daughter, Marie Irene, and said it was because of the ship.

“It had significant impact on him because it was the only ship he ever spoke about.”

Signalman Sutton married his wife, Alice, and they had two children in December 1918.

He left the Navy in 1920 and around 1922 he jumped ship in Australia, possibly while in the Merchant Navy.

He sent money home to his family until they later sailed over and he had four more children before his death in 1974. During his lifetime he worked at an ammunitions factory and was involved in the unions and politics.

Skilled dockyard worker Harold Herbert Back was not supposed to be working when the explosion tore through the ship.

He had just recently been promoted and the day before he was asked if he would take the place of a colleague who could not work.

The 48-year-old, who lived in Meyrick Road, Sheerness, agreed as he felt the workmate would do the same for him in the same position.

He was a well-respected member of the community and was a former Grandmaster of the Sheppey Oddfellows, a social and charitable organisation.

Mr Back and 75 other dockyard workers were taken out to the ship, moored about three miles from Sheerness on the number 28 buoy, to carry out repairs and modifications.

His grandson Colin Walker said: “The Princess Irene is frequently discussed in the family and, of course, Harry being on the memorial.

“It’s such an important thing to remember. It’s been 100 years and we feel that it’s very important that he is not forgotten as well as his other fellow workers because it’s so tragic.” - grandson of victim, Colin Walker

“It’s such an important thing to remember. It’s been 100 years and we feel that it’s very important that he is not forgotten as well as his other fellow workers because it’s so tragic.”

The 69-year-old, of Dymchurch, will be attending a service today at 11am at Sheerness War Memorial in Bridge Road, Sheerness, where his grandfather’s name and those of the 75 other dockworkers are written.

One of his daughters, his mother, wife and two sisters, Julie Dodd and Jenny Ralph, will also be in attendance.

Later on, Mr Walker and three relatives will be among those going out on a boat from Queenborough Harbour to the spot above where the wreckage lies to lay wreaths on the water.

About 50 families have been invited to the commemorations, with some relatives travelling from as far as Tasmania, Australia and Canada.

Blue Town Heritage Centre will be hosting a private function on the day and has recently unveiled an exhibition, with a model of the ship, about the tragedy.