Sentineling or Sentinelling: How To spell?
The word Sentineling is misspelled against Sentinelling, which is present continuous of "Sentinel"
Sentinelling has double "ll" is mispronounced as "l"Remember double 'LL' in between the strings sentine & ing which should not be misspelled with single 'L'
Wrong Spelling:  sentine-l-ing  Correct Spelling:  sentine-ll-ing 
Find more wrongly spelled words of Sentinelling to spell it well.