General diesel question

Can anyone explain to me the difference in HP and torque as it applies at the propeller?? Diesels produce a lot more torque, does that mean a 120hp diesel can turn a bigger prop than a 120hp gas engine. If this is true, would a 120hp diesel be able to push a boat a little faster than a 120hp gas since it can turn more screw at the same RPM???? Inquiring minds want to know. ???