Conversation so far:
What are some world record attempts that Richard Branson has made?
he attempted the fastest Atlantic Ocean crossing.
What is some information about the boat he used?
His first attempt in the "Virgin Atlantic Challenger" led to the boat capsizing in British waters and a rescue by RAF helicopter, which received wide media coverage.
Are there any other notable record attempts that Branson made?
1991, Branson crossed the Pacific from Japan to Arctic Canada.
How long did it take him?
This broke the record, with a speed of 245 miles per hour (394 km/h).
Did he fail any attempts?
Branson and his children made an unsuccessful attempt.

Question: What was this unsuccessful attempt?
Self-contained rewrite: What was the unsuccessful attempt, made by Richard Branson and his children, at crossing the Pacific from Japan to Arctic Canada?