What is the origin of garboard? There seems no clear description of it's
origin in the OED. The lack of reference suggest it came from elsewhere
and the French equivalent is Galbord. But what is 'Gal' you ask? It may
be that this is an adulteration of Caul which is a term given to the
amnion sac. Sailors though this membrane could protect them from
drowning as it kept water out...

Intriguing, but could it be true?

On the other hand, it has been suggested that it might be related to
'gaderenbord' (Winschooten 1681) the Dutch for 'gather' plus board. But
what does it gather -aren't the other boards are laid next to it?

Finally, 'gar' might be derived from 'gal' which is a spike -and this
idea is prompted by the appearance of garfish (as spotted by DSK). Is
the garboard not spiked into the keel?

Any other ideas?

Cheers