IT was no idle threat and his shipmates were fearful.

James Whelan unashamedly boasted he had killed twice before, first in Dublin and then in London – and now he was ominously at loggerheads with the second mate.

"Look here," he snarled. "I am going to take a solemn oath. If he at any time takes a capstan bar or belaying pin on me, I am going to kill him dead at my feet, and the man who has half a word to say about it, I will shove my knife through his heart. So help me God."

Hours later, the second mate George Richardson was dead.

It was in October 1886 that the surly Whelan, 23, shipped aboard the Emma L Shaw that carried general merchandise from New York to Buenos Aires.

And within a week he had fallen out with Richardson over his work.

When fellow seaman took the second mate's side by remonstrating with him, the Canadian uttered his murderous threat.

For hours he brooded – and then struck after being relieved of the wheel, snatching a two foot long iron pin in search of Richardson who had been keeping a lookout at the stern of the ship on what was a moonlit night, telling another shipmate in passing that he intended to kill him and had kissed the Bible to that effect.

Whelan struck the mate with such force that he had no opportunity to react and was pushed overboard on the port side. Deviously he then shouted: "Man overboard."

A boat was lowered and a thorough search of the area conducted but Richardson's body had been consigned to the deep.

Whelan believed he could count on the silence of the two semen, Wilson and Forsman, for fear of reprisals but eventually word reached the captain.

Whelan was disarmed of his sheath knife and put in irons.

"Subsequently he used expressions showing malignity towards the deceased, saying he was glad to kill him," prosecutor Mr Folkard was to tell jurors. "On arrival at Buenos Aires he was brought before the consul and sent back to Southampton. The prisoner made several statements, alleging that the deceased had attacked him, that he had struck the deceased in self defence, and the latter had accidentally fallen overboard.

"All this, the witnesses declared was entirely untrue."

Folkard was making his opening statement on May 5, 1886, when Whelan appeared at Hampshire Assizes, charged with murder on the high seas on a British registered vessel.

With Wilson and Forsman having delivered their evidence, the Crown closed its case.

The defence barrister, Greenwood who had been assigned by the judge, Mr Justice Day, to represent Whelan, told the court the defendant wanted to make a statement.

Permission granted, he rambled for more than an hour in a thick Irish accent, principally claiming the pair had been good friends until Richardson had threatened to hurt him for failing to endorse his report that the captain had intentionally started a fire on the ship as a bogus insurance claim.

However, under cross-examination, he meekly confirmed his oath of kissing the Bible.

Without leaving their seats, jurors consulted for about 10 minutes before convicting him of murder but with a recommendation for mercy on the grounds of provocation.

But in donning the infamous black cap, the judge told Whelan: "You have been found guilty on the most clear and satisfactory evidence. It is impossible to doubt that you had deliberately and without provocation caused the death of the unfortunate Richardson."

Whelan, showing little emotion, was removed from the dock by two warders.

A petition was rejected by Home Secretary Sir Richard Cross, Whelan receiving the news with complete indifference, and he was executed on May 31 alongside another murderer in Albert Brown who had slaughtered a younger shipmate on another vessel for his money outside Winchester, walking with commendable firmness to the scaffold where as a Roman Catholic he clutched a crucifix until his dying breath.