Inflatable dinghy and pool toy

Also: pool toy, rubber dinghy, slackraft

Pool toys made of thin PVC are meant for the swimming lake, not for trips. A packraft is a proper, robust boat.

The English Wikipedia calls such boats slackrafts: built for nothing more than calm water. They lack tear strength, abrasion resistance and usually stiffness too. On rivers and lakes away from the shore they are dangerous.