Answer:
Step-by-step explanation:
The sentence "My friends and I climbed aboard a canal boat and explored it" is a compound sentence and it is declarative.
It is compound because it consists of two independent clauses joined by the coordinating conjunction "and":
1. "My friends and I climbed aboard a canal boat"
2. "explored it"
It is declarative because it makes a statement. The correct end mark of punctuation for this sentence is a period.