When adding a suffix that begins with a consonant, the general rule is to

When adding a suffix that begins with a consonant, the general rule is to:
1. Change y to i
2. Double the letter L if the word ends in L.
3. Retain the letter y if the word ends in vowel + y.
4. There are also other words that the base word is just retained and then add the suffix at the end. 
Consonant suffixes include: -ly, -less, -y, -ship, -ment, -ness, -ful, -es