Why is a catamaran so named?

[Nostrodamus]

If a boat with three hulls is called a trimaran and a boat with one hull is called a mono hull why is a boat with two hulls called a catamaran and not a bimaran.
Is it because all these boats seem to be named top cat or something similar and they don’t want to call it Top Bi or something?

 

[boatbuilder]

Catamaran is, I believe a Tamil word for tied logs. Or so James wharram once told me.

 

[pvb]

Catamaran is, I believe a Tamil word for tied logs. Or so James wharram once told me.

Correct. It's from kattu "to tie" and maram "wood, tree".

 

[Nostrodamus]

Thank you for letting me know.
A pretty apt desription.