This was a popular model here until they deleted it. Illegally so since Benchy was originally released as CC, and once that license has been granted it can not be taken back.
In any case here it is again. The turrets are separate pieces so that they can rotate.
The smoke used in the picture can be found HERE.
Supports are needed for the turrets.
Supports are not required for hull.
The user re-uploaded this model. The user is not the original author of the model.