I made each sentence two words shorter so its easier to say. (I removed 'decided to' or used simpler words.) Here are four short versions:
- 'Islands are like big boats that park and rest in the big blue sea.' (14 words)
- 'Islands are like large boats that park and rest in the deep blue sea.' (14 words)
- 'Islands are like big ships that park and rest in the warm blue sea.' (14 words)
- 'Islands are like big boats which park and rest in the bright blue sea.' (14 words)
Pick the one you like best!