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We present phase-resolved optical spectroscopy of the eclipsing nova-likecataclysmic variable EC21178-5417 obtained between 2002 and 2013. The averagespectrum of EC21178-5417 shows broad double-peaked emission lines from HeII4686 \AA{} (strongest feature) and the Balmer series. The high-excitationfeature, CIII/NIII at 4640-4650 \AA{}, is also present and appears broad inemission. A number of other lines, mostly HeI, are clearly present inabsorption and/or emission. The average spectrum of EC21178-5417 taken atdifferent months and years shows variability in spectral features, especiallyin the Balmer lines beyond H$\gamma$, from pure line emission, mixed lineabsorption and emission to pure absorption lines. Doppler maps of the HeII 4686\AA{} emission reveal the presence of a highly-inclined asymmetric accretiondisc and a two spiral arm-like structure, whereas that of the Balmer lines(H$\alpha$ and H$\beta$) reveal a more circular accretion disc. There is noevidence of a bright spot in the Doppler maps of EC21178-5417 and no emissionfrom the secondary star is seen in the tomograms of the HeII 4686 \AA{} andBalmer lines. Generally, the emission in EC21178-5417 is dominated by emissionfrom the accretion disc. We conclude that EC21178-5417 is a member of the RWTri or UX UMa sub-type of nova-like variables based on these results andbecause it shows different spectral characteristics at different dates. Thisspectral behaviour suggests that EC21178-5417 undergoes distinct variations inmass transfer rate on the observed time scales of months and years.

A spectroscopic analysis of the eclipsing nova-like EC21178-5417 -- discovery of spiral density structures