援救 

Pinyin: yuán jiù 
Meaning：Rescue 
Sentence: 救生艇被派出援救下沉轮船上的水手们。The lifeboat was sent out to rescue the sailors from the sinking ship.

More:

援： 

Pinyin: yuán
Meaning: To help; to assist
Radical: 扌
Stokes: 12
Traditional: 援
Common words/Phrase:
援引 [yuán yǐn] 【quote】
援外 [yuán wài] 【aid foreign】
援军 [yuán jūn] 【reinforcement】
援用 [yuán yòng] 【cite】
援兵 [yuán bīng] 【relief】

救： 

Pinyin: jiù
Meaning: To save; to assist; to rescue
Radical: 攵
Stokes: 11
Traditional: 救
Common words/Phrase:
救援 [jiù yuán] 【to save】 
救助 [jiù zhù] 【salvation】
救命 [jiù mìng] 【help】
救护车 [jiù hù chē] 【ambulance】
救济 [jiù jì] 【help out in a disaster with cash or goods】