Who saved Romke Fopma's family in 1942 when their ark sank in Echtenerbrug?

Romke and Froukje Fopma from Leeuwarden traveled with their three young children on a small ark to Vollenhove in 1942, but the boat sank in Echtenerbrug. They were saved by the inhabitants, but who were they? The family is looking for these people. Romke and Froukje were Yvon van der Meer's grandfather and grandmother and she and her cousin Jeltje Fopma would very much like to know who these rescuers were, in order to thank them - after almost 85 years.