Because the tide has gone out, both the teenagers and the rafts they were using have been stuck in the sand.
1.) I think this is parallel.. "the rafts they were using" is the same as "the rafts that they were using". just a noun + relative pronoun and modifier. on another forum someone claims that these are not parallel.
2.) both/and should join teenagers and rafts for a compound subject that should use "have" correct?
thanks