PROPS

[hydromann]

Hey guys im running a yamato 80 on a 12 foot hydro. looking for some prop options, the motor has the stock prop shaft and stock brass prop. does anyone know where I can get a better prop that will fit that shaft. the boat is topping out at 40 mph and rpm is low I need a smaller pitch prop. thank you for any advise you can offer. Jeff

[kraazyboat]

do you know the pitch of the prop

[hydromann]

No I'm not really sure of the pitch but boat has no air traps may try adding them first any idea on best wood to use for that?

[Shane_B]

Saw some old boats retrofitted with aluminum airtraps (cut from about 1/8 thick sheet...), had about an inch or so flange to screw to chine and then a tab to screw to back of sponson

[kraazyboat]

call me 815 990 6455

[Smitty]

The bronze props that came with the Model 80 in the 1970s and maybe later have too little pitch for you, not too much. As originally designed for use in Japanese pari-mutuel racing in big marine stadiums, the stock prop had to push a heavy old-fashioned step-hydro with a high-drag bottom shape. It isn't a great design, but George Lockhart in Tacoma re-pitched a number of them as much as he could, and these would get a light hydro to about 57mph indicated. There is only so much pitch that can be put into this wheel, but one of Lockhart's might have been about right for your big boat (and they were not too bad as a first prop for that engine on a runabout). I have no idea if Lockhart is still active, or even still among us, but people here can direct you to other prop-men.

Your boat sounds a bit large for an unmodified Y-80, and it surely does need airtraps. Mahogany, spruce, and white cedar have all been used, about 1/2" wide, as has 1/8" 6061 aluminum. Sounds like kraazyboat will give you all the details you need.