  The Skyrme-Faddeev model is a (3+1)-dimensional model which has knotted,
string-like, soliton solutions. In this paper we investigate a Skyrme-Faddeev
model with an SO(3) symmetry breaking potential. We then rescale this model and
take the mass to infinity. This infinite mass model is found to have compact
knotted solutions. In all of the investigated massive models we find similar
charged solutions as in the usual, m=0, model. We also find that their energies
follow a similar power growth as the m=0 model.
