Dear Sirs,<br />I am user of light inflatable boat - pirogue for 1 - 2 person ( Sevylor PR285- weight 25lb)( new model is PR285HF) and electric motor 12V/12A Sevilor SMB12, weight 4lb, maximal thrust 12lb, maximal speed ~ 4 - 5mph( with full battery, ~ 13.5V).<br />Plastic propeller (of electric motor SMB12) have 3 blade, diameter 128 mm, pitch ~40mm, maximal speed = 3580 rpm.<br />There are big troubles with the electric motor such as: insufficient power, weight battery (one battery 7Ah/12V = 6lb), short time of full power (the voltage is lowering too fast), short autonomy, especially when the sea ( lake ) isn't still.<br /> I want to substitute electric 12V motor with simply 2 stroke ~9 lb light gas trimmer engine, about 1HP/ 8000rpm , joined with flex - cable in aluminum tube to(lower unit and) propeller.<br />There are two alternations : first alternation - engine joined with flex cable to propeller designed for high speed<br />8000rpm;(small pitch, 6 blade ?, diameter ~ 5.5 inch?); problem - propeller, lower efficiency ( axial bearing for propeller - lubrication ?)<br /> second alternation - engine joined with flex - cable to lower unit and usually 3 blade propeller for usually speed <br />(3500 - 4000 rpm); problem - lower unit : sealing, bigger prize and maintenance.<br />In both alternations, maximal thrust 18 - 20 lb is needful , foreseeable maximal boat speed ~ 6 - 7.5 mph. <br />Can anubody suggest me best solution and suitable propeller ?<br />P.S. As well, I have 4- person inflatable boat and outboard.
