Lazing on a houseboat while watching the sun shimmer on the water of San Francisco Bay, Otis Redding felt moved to pick up his acoustic guitar and begin strumming.

In such a beautiful and inspirational setting the lyrics flowed effortlessly.

“Sitting in the morning sun. I’ll be sitting when the evening comes. Watching the ships roll in.

"And then I watch ’em roll away again, yeah.”

It was one of those rare moments when an artist knows immediately that he’s just created a masterpiece.

Redding remarked to his manager at the time: “I got it. This is my first million seller.”

He was right about (Sittin’ On) The Dock Of The Bay, but tragically would not live to enjoy its huge success. 

Just three days after recording the song, which regularly appears on lists of the greatest ever written, the King of Soul was dead aged only 26.

The evocative Dock Of The Bay became the first posthumous Number 1 in the US a few weeks later.

It’s 50 years on Sunday since Redding and four of his band members perished while flying to a concert in Madison, Wisconsin.

To this day the cause of the crash remains a mystery. Born in Georgia in 1941, Redding left school when he was 15 and worked as a well driller but his dream was to be a musician.

The former Baptist church choir member performed at talent shows to win cash to support his family and became a backing singer for Little Richard. 

His first single, These Arms Of Mine, was released in 1962 and Redding soon became established as one of the US’s most popular R&B and soul singers.

His success allowed him to buy a 300-acre ranch, called the Big O, in his home state where he lived with his wife Zelma.

Redding was one of the first soul singers to appeal to a mainstream pop audience, cementing his appeal with a cover of Try A Little Tenderness and his own song Respect.

He and his band toured Britain in 1966 and The Beatles were big fans.

The following year readers of Melody Maker magazine voted Redding Top Male Singer, displacing Elvis Presley.

Also in 1967 Redding sold more records than Frank Sinatra and Dean Martin combined. Appearing at the Monterey Pop Festival alongside established white performers – including The Who – widened his reach.

That summer he and session guitarist Steve Cropper wrote Dock Of The Bay in Sausalito, on the west coast of California, while taking a break from touring. 

However, Redding’s record label Stax was not convinced by the song which was unlike his previous work and there was resistance to a recording.

He finally got his way on December 7 when he went into the studio, but it’s said that he still didn’t have a final verse.

The story goes that Redding simply whistled it, intending to return to Memphis later to complete the work.

A different version is that he forgot the words for the fade out at the end of the record and ad-libbed. In either case, three days later he was dead.

Redding never heard the final version of his greatest song, as its memorable sound effects of crashing waves and seagulls were added posthumously.

Like many successful touring musicians in that era Redding had purchased a private plane for him and his band The Bar-Kays to crisscross the vast US.

On December 9 they appeared on a TV show in Cleveland, Ohio, and next day set out to fly the 500 miles to Madison, Wisconsin, where they were due to perform at The Factory nightclub.

It was a filthy day and it’s claimed that pilot Richard Fraser was warned about stormy weather, but decided to take off. James Brown also claimed in his autobiography, The Godfather Of Soul, that he warned Redding not to fly. 

Redding’s final telephone call was to his 24-year-old wife and their three children back on the ranch.

The Beechcraft plane was four miles from its destination when Fraser radioed for permission to land.

Then on its approach the aircraft plunged into icy Lake Monona, coming to rest briefly on the surface before disappearing.

Four band members, their valet and the pilot died along with Redding whose body was found the next day still strapped in his seat.

He’d been knocked unconscious on impact and drowned.

His widow Zelma, now in her mid-70s, says: “You never get over something like that. At the time, you’re looking for him to call, you’re looking for that gate to open, you’re waiting for him to come home. It takes a long time for it to sink in.”

The sole survivor was trumpet player Ben Cauley, a non-swimmer, who was thrown clear and clung to a cushion until he was rescued.

He died in 2015, aged 67. Another band member, James Alexander, lived because he travelled by commercial aircraft as there was no room on board the Beechcraft.

Eight days after the crash 4,500 mourners attended Redding’s funeral, in Macon, Georgia and Dock Of The Bay was released in early January 1968 on a tide of emotion.

It remains Redding’s only Number 1, also reaching Number 3 here, and selling four million copies worldwide. Since then the record has been covered numerous times, by artists as diverse as Pearl Jam, Michael Bolton and Tom Jones, who said: “It’s one of those breathtaking songs that simply stops you in your tracks.”

At the time of his death Redding had recorded enough material to fill three more albums, which were also released posthumously, so the hits kept coming.

He has been described as “the most influential soul singer of the 1960s” and numerous bands and stars have said he inspired their work including Led Zeppelin, Marvin Gaye, Aretha Franklin and The Doors.

I n 2011 Rolling Stone magazine ranked Redding at Number 21 on their list of the greatest recording artists of all time.

Also that year Kanye West and Jay-Z released Otis, which samples Try A Little Tenderness.

The cause of the fatal crash was never established, although numerous theories have been put forward including sabotage.

More likely it was a combination of the poor weather and pilot error, but that year alone there were more than 600 fatal crashes in the US involving private aircraft and investigations were not thorough. However, it was noted that the pilot was used to flying in the warmer south and was unfamiliar with the wintry conditions in Wisconsin.

Jonathan Gould, author of a biography of Redding called An Unfinished Life, says: “The great tragedy is that Otis Redding had everything to live for. With the impending release of Dock Of The Bay he was on the cusp of a new kind of musical success. It went on to become one of the world’s mostplayed songs.”

To mark the anniversary of Redding’s death all his albums are being released in a box set, while a foundation in his name encourages young musicians in the US to fulfil their dreams. Gould adds: “The question that still hangs over his career is ‘where might it have gone?’ Instead, Dock Of The Bay was Otis Redding’s epitaph.”