Wiktionary
keelless
a. Of a water craft; having no keel
Usage examples of "keelless".
New obstructions were always being encountered, or a bumping acquaintance with old ones was being renewed, Flood times were the worst because the surging waters hid dangerous rocks and made the keelless vessels impossible to steer.
Thick smoke from his revolver barrel drifted away in lengthening streams, and the side-wheeler slid downstream on its flat, keelless bottom.