 The concept of small sailing frigates with a complementary set of oars ( or " <unk> " ) was not new . The English Tudor navy had used small " <unk> " in the mid @-@ 16th century . In the 1660s its successor , the Royal Navy , equipped the equivalent of sixth @-@ rates with oar ports on or below the <unk> . During the 18th century the Russian Navy introduced " <unk> " , Baltic variants on the Mediterranean <unk> , for inshore duties . The <unk> were good <unk> , could be rowed if necessary and had more guns and greater stores than galleys ; they were also less expensive to maintain . The Russian designs influenced Chapman and the Swedish naval commanders . Consequently , Chapman 's designs for new ships were <unk> on those principles , but with adaptations to archipelago warfare . 
