  We address the problem of modeling the far-infrared (FIR) spectrum and
deriving the star-formation rate (SFR) and the dust mass of spiral galaxies. We
use the realistic physical model of Popescu et al. (2000) to describe the
overall ultra-violet (UV), optical and FIR spectral energy distribution (SED)
of a spiral galaxy. The model has only three free parameters: SFR, dust mass,
and the fraction of the UV radiation which is absorbed locally by dense dust in
the HII regions. Using this model, we are able to fit well the FIR spectra of
62 bright, IRAS galaxies from the "SCUBA Local Universe Galaxy Survey" of Dunne
et al.(2000). As a result, we are able to determine, among others, their SFR
and dust mass. We find that, on average, the SFR (in absolute units), the
star-formation efficiency, the SFR surface density, and the ratio of FIR
luminosity over the total intrinsic luminosity, are larger than the respective
values of typical spiral galaxies of the same morphological type. We also find
that the mean gas-to-dust mass ratio is close to the Galactic value, while the
average central face-on optical depth of these galaxies in the V band is 2.3.
Finally, we find a strong correlation between SFR or dust mass and observed FIR
quantities like total FIR luminosity or FIR luminosity at 100 and 850
$\mathrm{\mu m}$. These correlations yield well defined relations, which can be
used to determine a spiral galaxy's SFR and dust-mass content from FIR
observations.
