Stuck fermentation ?

I brewed a Belgian Dubbel about twelve days ago with a 1.084 OG and I'm only down to about 1.040. I also transferred the beer into secondary tonight because I'm going to need my big mouth fermentor for a dry hopped IPA. Even at the peak of fermentation it wasn't a vigorous one which is what I was expecting with a 1.084. The fermenter hasn't been below 70 degrees since I pitched either. Maybe I under pitched? It was my first time using a new denver yeast ( inland island), which I was told I didn't need a starter for because supposedly the viles have about twice as many cells as white labs. So I didn't use a starter. Now I wish I did. Any ideas what I can do to get this beer down to about a 1.015? Thanks for your help

 

Correct

 

I'm not familiar with that yeast but I never trust that 1 vial (or 1 pkg of dry) will be adequate for a big beer. Once I'm up over 1070-ish, I always make a starter or pitch 2 packs. That said, I know a lot of Belgian yeasts are known to get stuck and need some "help". Try rousing the yeast and warming it up to the high 70's for a few days. If that doesn't work, you can try pitching another pack. Also, be aware that some Belgian yeasts are very slow to finish. Good luck.