Boat props are not a bit alike as in OPEN non restricted water and thusly propulsion is not the same as jets are confined within the jet. There was a great story published in Popular Mining Mag(Action Mining) called'SIZE WISE" back in 1/87 about a fella who need a 6" waaaaaaaaaay out in the backcountry in a spot even a chopper couldn't fly. We worked like crazy trying to reduce all components to the smallest size to make a BACKPAKABLE 6" over/under run with a hi-dome pump attached to a tiny 8hp briggs IC. He spent the whole summer,thanked me everytime in town, and made a fortune but unbeknownst to me I found the article after he was murdered for his gold. 4" in to produce pressure 3" or so out to REALLY blow that thang up. More supply than demand exactly like a air compressor,hydrolic pumps and municipal water systems. Yes you can conical out the inductors,but must be bigger at the top and then tooooo big to fit into the pressure chamber so you monster out the chamber. ALSO the 11 degree angle of the inductors all meet down the inside the jet and spread out to completely fill the entire chanmber with push force. Take any jet and insert a dowel into the jet,where it hits midstream is the sweet spot,do the same with a dual,now a tri as THAT is what determines how many jets. 1 not enough,2 still not,but 3 does it just right and fills the entire tube with push force. Sure you can go 5-6-7-8 whatever but why ,as then small force by smaller inductors provides 8 miniscule forces instead of 3 much bigger forces. Length of jet after the sweet spot is also important to provide the VOLUME to support the push. Look at any jet after a few 100 hours of use-insert dowel/stick and bingo there is that bump/wear spot from using the side of the jet to PUSH the flow and NOT the center sweetspot which is where you want to be. Take a plate and try and balance with 1 finger -now 2-then 3 WOW instantly magic as equalibrium in form and function is achieved,same as jet. Perfect example is the Dahlke mini tri jet---jet tube flow met in the hose(which was curved) and not near the suction of the longer full jetted model,another shining example of the physics involved. A jet is NOT a simple affair. Still trying to get ol'Prospectors Casche discussion by a half dozen dredge masters and buddy engineers who went into this all in explicit detail. Goota go mining no mo'time to play today-OMG past 8 *&^%$# late already--John
