Merc Sea Pro 25 / Power Tech prop question

Discussion in 'Prop Shop' started by el9surf, Apr 4, 2013.

  1. el9surf

    el9surf Well-Known Member

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    I just got my new powertech prop. It is a 4 blade 10 inch 10pitch SRA4 tohatsu hub

    It slides on just fine however the blades are so swept back that they bump the anode fin that hangs down from the bottom side of the cav plate.

    Does that Anode serve any purpose aside from corrosion resistance? If I cut the fin in half would it affect anything? If I were to cut it I think the prop would rotate without hitting.
     
  2. Dillusion

    Dillusion devilray snob

    The fin is also called a 'torque tab'. It keeps your motor tracking straight in the water...sort of like an adjustable 'alignment' on a car. If your outboard is pushing to the right, you move it to the right, etc.
     

  3. HaMm3r

    HaMm3r Well-Known Member

    Mine fell off and I didn't even notice, so it's not critical. But as Matty said, if you're getting steering torque then it can counteract some of it.
     
  4. el9surf

    el9surf Well-Known Member

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    What if I just cut a notch into it, or cut the fin in half? Then the tab is still there to serve its purpose and the blades will clear.

    I may just take it off to test the prop before I make any permanent adjustments.
     
  5. el9surf

    el9surf Well-Known Member

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    I sanded a small notch into the torque tab and took the boat to the river for some testing. Rpms jumped from 5000 to 5700 and top speed was 28.5 on my gps. Hole shot was scary quick and the blowout I previously had was all gone. The results of the new prop were a bit shocking to say the least. The tabs I have are now necessary. The torque tab will be necessary to fix the ppulling to the left.