Crazy boating brothers Ralph and Bob Brown have come up with a mad idea to surpass their own world record-breaking Bermuda Suicide Challenge.

Last year, the Floridian pair defied the advice of maritime experts by trekking unescorted from North Carolina to Bermuda and then on to New York harbour in a 21-foot flats boat — the world's longest ever unescorted oceanic crossing in such a vessel.

Now they're planning to go a step further in the same boat with a voyage from Boston to Ireland, via Canada, Greenland and Iceland.

It all means one unusual reference to Bermuda in the Guinness Book of World Records could turn out to be short-lived.

Asked why he and his brother are taking on an even more difficult challenge, Ralph Brown said: "Why not? The last trip was a blast.

"The truth of the matter is that I am trying to build a boat company. I really think I have the world's most seaworthy flats boat.

"Enough critics said we just got lucky. Well, yes, God did bless us. However, let's not take away from the boat. We went through a small storm on the way over. The waves were at least eight foot, and the winds were at least 30 mph. The boat did well.

"It took Bob all of two seconds to decide he wanted to go again when I asked him. This time, his wife says OK."

A book about the brothers' Bermuda trip is available via www.bermudachallenge.com