C4/2010M M/S IDA 1 (FIN), grounding and sinking in Kvarken, Finland on 17 August, 2010

M/S IDA 1 which had two Volvo Penta IPS-drives, departed on 17th August 2010 from Fjärdskär in Mustasaari off Vaasa for a tourist tour to Mikkelinsaaret with 20 passengers, skipper, deck man and two dogs onboard. After a turn onto Uddskär fairway she hit at full speed a stone at ca 11.10 o’clock. The stone was at such a depth that the hull glided over it and only one drive hit it. The under water part of the drive, the pod, bent backwards making a big hole in the ship’s bottom and broke the transom. Consequently, the engine room became quickly full of water. Thereafter water flooded slowly through the bulwark and door between the engine room and passenger spaces to the passenger spaces. Boat’s after end sunk in about half an hour and hit the sea bottom, but the fore end stayed above the sea level. Thanks to this the time for the evacuation became long enough.

Deck man alarmed the Emergency Response Centre by her mobile, which took some minutes. The MRSC Vaasa alarmed two patrol boats of the Vallgrund coast guard station at 11.17 o’clock. The grounding had been observed by eyewitnesses so that two private boats arrived already in ca 10 minutes at the place of the accident evacuating the passengers, crew and dogs staying on the fore deck. Coast guard’s first patrol boat arrived to M/S IDA 1 ca 20 minutes later, only ca 10 minutes before the aft sunk. A bigger patrol boat arrived 10 minutes after the first one, just before the aft hit the bottom. No persons were injured seriously in the accident, but the boat was heavily damaged. The accident did cause no environmental damages nor did oil leakages come up.

One life raft did not get loose at all, and another opened upside down. Therefore it was important that the private boats arrived at the place of the accident quickly. If the civil boats had not arrived persons onboard could have been waiting safely on the fore deck for the coast guard to arrive. However, the situation had been much more serious because several persons had to have packed themselves very tightly on the inclined deck. As a reserve, there was the upside down floating life raft, which might also have given a place for rescue.

Another motorboat of type Jeanneau Prestige 42S had a few months earlier hit a ground off Inkoo and sunk . M/S IDA 1 and this boat had two similar Volvo Penta IPS -units. Based on the marketing info by the manufacturer and on data in some drawings the pod should shear off without forming a leakage. Because not a single of the three pods which hit a stone broke off in the manner specified by the manufacturer, Safety Investigation Authority decided that factors related to the structure of IPS units would be studied in co-operation by both investigations. Problems were found concerning the shear off-feature of the propeller units according to the so called strength pyramid-principle and in the integration of the propeller unit and the hull.

Investigation commissions demounted and inspected the damaged unit of M/S IDA 1. They observed that the shear off process had begun as planned by the manufacturer, but had not continued fully to the end and the pod did not shear off.

The construction of the aluminium hull was a result of two rebuilds: in 1999 the aft part of the hull was lenghtened by 1.4 meters and in 2006-2007 the construction was adopted for Volvo Penta IPS-drive as the waterjet propulsion was removed. Inspection of the after part of M/S IDA 1 showed that the strength of the hull construction around the IPS-drive was weaker than shown in some drawings of Volvo Penta from that time. The requirements of Volvo Penta for the hull construction of M/S IDA 1 remained unknown.

The descriptions of the IPS unit and its inspection as well as of the hull construction in the boat’s after part are attached as annexes to both original investigation reports (in Finnish and Swedish).

Two technical solutions in the vessel led to a more serious accident resulting to the sinking of the aft. Firstly, the pod did not shear off as planned by Volvo Penta. Secondly, the fore bulkhead of the engine room was not watertight. (No regulations require a watertight bulkhead in a boat like M/S IDA 1). However, the doors between the engine room and passenger’s spaces were closed. Consequently, the flooding continued more slowly through the bulkhead.

The reason of the grounding was skippers momentary lose of attention at the adjustment of the course. He had taken part in a discussion by some passengers with the deck man and showed on the nautical chart how one should navigate to Mikkelinsaaret from the north.

Safety Investigation Authority recommends that the Finnish Transport Safety Agency requires on small passenger crafts that one should eliminate the possibility for discussion between passengers and the driver by a partition screen or similar. During the safety information announcement to the passengers before the departure it should specially be emphasized that it is not allowed to discuss with the driver during the voyage. Moreover, labels in several languages with this content should be placed around in the boat. Additionally it is recommended that the crew should carry out regularly rescue drills and also notify that in the logbook. Also, quality system should be required for all passenger vessels including small ones in seasonal traffic in a reasonable extent.

Manufacturer of the Volvo Penta IPS unit is recommended to verify the function of the strength pyramid-principle, the requirements for the hull construction and for the fastening of the pod to the hull as well as to remind the buyer of the IPS-system that especially the instructions concerning pod’s fastening to the hull must be followed in detail.

This summary is more detailed than summaries in Finnish and Swedish, because it is the only description of this accident in English.

C4/2010M Report (pdf, 6.06 Mt)

C4/2010M Report (pdf, 6.06 Mt)