A case of a mispelled word

The English language makes it difficult to teach spelling. There doesn't seem to be rhyme or reason in some instances to the way things are spelled. Teaching young children to spell phonetically works often but sometimes it can be tricky. For instance this week Harrison had for and more. How do you explain to a child why one has an e and the other doesn't? He was able to remember the word more has a e because I kept saying more has one more letter than for.

Sometimes spelling can also be confusing because certain letters have a similiar sound if not spoken clearly which was apparently the case when I called out another of Harrison's words - ship. He spelled it S-H-I-T. Haley was in the next room laughing and trying hard not to myself, I said "No spell ship" (making emphasis on the letter p).   I didn't want to explain to him what he just spelled because I knew that he might find it funny and repeat it. We went through the whole list again and when we got to ship he once again spelled it with a t but quickly changed to a p. 

The test is today and I am hoping that he spells ship correctly. I can only imagine the expression on his teachers face if he inserts a T where the P is suppose to be. She might wonder exactly what Harrison is learning at home.