  We investigate the Drinfel'd doubles $D(\Lambda_{n,d})$ of a certain family
of Hopf algebras. We determine their simple modules and their indecomposable
projective modules, and we obtain a presentation by quiver and relations of
these Drinfel'd doubles, from which we deduce properties of their
representations, including the Auslander-Reiten quivers of the
$D(\Lambda_{n,d})$. We then determine decompositions of the tensor products of
most of the representations described, and in particular give a complete
description of the tensor product of two simple modules. This study also leads
to explicit examples of Hopf bimodules over the original Hopf algebras.
