semi-rigid
Concise Oxford English Dictionary © 2008 Oxford University Press:
semi-rigid/sɛmɪˈrɪʤɪd/
▶adjective
- 1 (of an airship) having a stiffened keel attached to a flexible gas container.
- 2 (of an inflatable boat) having a rigid hull and inflatable sponsons.
'semi-rigid' also found in these Oxford entries:

