Patent ID: 9701379
Date: 2017-07-11
CPC Classifications: B63H

Claim:
1. A propeller including: a hub which is hollow; a plurality of primary blades extending substantially radially outwardly from the hub, with each primary blade including a blade face, a blade back and a root section; wherein an inner volume of the hub is in flow communication with a volume radially outwardly of the hub; a set of secondary blades located on a hub insert which fits inside the hub, wherein an annular volume is formed between an inner surface of the hub and an outer surface of the hub insert, with the secondary blades disposed inside the annular volume; and tertiary blades which extend from the hub insert, with each tertiary blade located between two adjacent secondary blades in order for the secondary blades and the tertiary blades to divide the annular volume between the hub and the insert into alternating water and exhaust gas flow passages.