HAVO (higher general secondary education) and VWO (pre-university education) pupils from Develstein College in Zwijndrecht were on a sailing trip that was due to last from Tuesday 6 June to Friday 9 June. They were sailing on the Friesian lakes and on the IJsselmeer under the watchful eye of their teachers. All in all, there were 26 pupils and 2 teachers on this trip on board a chartered two-mast clipper.
On 8 June 2006, an explosion occurred on board their ship at about 7.50 p.m. [NB. All times are local times.] At that time, the ship was moored in the harbour at Medemblik. At the time of this incident, there were eleven pupils on board the clipper. Some of them were preparing the evening meal, cooking on the gas rings on the four-ring cooker. Eight of the pupils on board were wounded, four of them seriously. At least three of the pupils have permanent injuries from the explosion.