MILAN, Aug 22 (Reuters) - A series of "indescribable,

unreasonable errors" by the crew led to the shipwreck in which

British tech entrepreneur Mike Lynch and six others died earlier

this week, the yacht manufacturer's CEO told Reuters on

Thursday.

The British-flagged Bayesian, a 56-metre-long (184-foot)

superyacht with 22 people aboard - 12 passengers and 10 crew -

capsized and sank on Monday within minutes of being hit by a

pre-dawn storm while anchored off the coast of northern Sicily.

"The boat suffered a series of indescribable, unreasonable

errors, the impossible happened on that boat ... but it went

down because it took on water. From where, the investigators

will tell," Giovanni Costantino said in an interview.

Costantino helms The Italian Sea Group, which

includes Perini Navi, the Italian high-end yacht maker that

built the Bayesian in 2008. The vessel has been refitted twice,

last in 2020, but not by Perini.

The CEO ruled out any design or construction errors, which

he called unlikely after 16 years of trouble-free navigation,

including in more severe weather than on Monday.

He blamed the Bayesian's crew for the "incredible mistake"

of not being prepared for the storm, which had been announced in

shipping forecasts. "This is the mistake that cries out for

vengeance," he said.

Costantino said passengers should have been summoned out of

their cabins and assembled at a point of safety while the boat

was being prepared for the storm by pulling up the anchor,

closing doors and hatches, lowering the keel to increase

stability and other measures.

Six out of 12 passengers died in the shipwreck, and five

bodies were found inside the wreck. Emergency services are still

trying to locate the body of the last missing person, Lynch's

daughter Hannah.

Had correct procedures been followed, all passengers would

have gone back to sleep after one hour "and the next morning

they would have happily resumed their wonderful cruise,"

Costantino said.

Another yacht anchored near the Bayesian escaped unharmed.

The captain of the sunken yacht and other crew members have not

commented publicly on the disaster, while Italian prosecutors

investigating it are due to hold a press conference on Saturday.