A wooden mast which broke suddenly on a Dutch historic sailing ship and killed three people on its deck had been rotting for at least four years beforehand, the Dutch Safety Board has found.
In the two years prior to the accident, the wood had rotted to such an extent that the mast “lost almost all its integrity”, a report by the Dutch Safety Board says.
The investigation report recounts how on August 21st, 2016, the captain of the historic sailing ship the Amicitia was just about to turn his ship into the port of Harlingen, after a week’s sailing on the Wadden Sea, when “catastrophe struck”.
A German family of twelve were on board, and three of them were helping to tie up the foresail when the 20-metre- high mast snapped, and the 6.5-metre-long top fell, with a number of parts, onto the foredeck.
The three people on the foredeck did not survive the accident, which the safety board has traced to wood rot. This was caused by water penetrating the mast, which could not drain out again and was trapped.
The investigation report says that “ on paper, many parties were involved in keeping the wooden mast safe, but none of these parties realised the severity of the situation”.
“ As a result, there was an uncontrolled safety risk on board the ship in question for a prolonged period”, it says, and. the captain and maintenance personnel “lacked expertise”.
The Dutch investigation reports note that it is common knowledge that a wooden mast can rot.
“ Provided this is identified in good time and adequately treated, it will not necessarily influence the structural integrity of the mast in question. It is therefore important that a mast is periodically inspected for potentially vulnerable spots,” it says.
“Specific know-how is required to be able to correctly assess the state of a mast and decide what type of maintenance personnel must be engaged,” it says.
In this case, it says there was “no maintenance plan for the mast in question, and it was not inspected periodically”.
“ This meant that changes and vulnerable spots were not identified. Because the captain himself did not have the relevant expertise, he relied on that of maintenance personnel he engaged. However, they did not have the necessary specific expertise concerning wooden masts either,” the report says.
The report identifies shortcomings in certification, and says the captain, who is also the owner of the ship in question, did not rely solely on the expertise of the maintenance personnel he engaged.
The mast certificate issued in 2012, which was valid until 2018, meant that “the captain was convinced that this safety-critical part of his ship met all the requirements”.
“ The private approval body had indeed inspected the mast and subsequently issued the certificate in question, more than four years prior to its breaking. Although, according to the law, this certificate was only valid for a maximum of 2.5 years, the approval body wrongly stated a validity of six years on it,” it says.
“This suggested that the mast still had a valid certificate at the time of the accident, whereas, in fact, the certificate in question had expired a good while earlier,” the report says.
“ The Dutch Safety Board has ascertained that, in the current situation, significant safety risks can go unnoticed when it comes to the inspection and certification of the sailing equipment on historic inland waterway vessels,” it says.
“ What is more, the certificates create a sense of false security by implying that the safety of a mast is guaranteed for a period which is much longer than the period needed for the rotting process to cause irreversible damage to the mast,” the report notes.
The Amicitia is one of 300 passenger sailing ships in what is known as the “bruine vloot”, or brown fleet, comprising historic ships chartered for passengers, which are part of Dutch cultural heritage.
“These ships, which are mostly commercially operated, are very popular with tourists, for school trips and for company outings,” the report says.
“The fact that three tourists have died as a result of the apparently sudden breakage of a mast raises questions about the safety of passengers on similar ships and the supervision of the sector,” the report notes.
