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  1. #1
    Join Date
    Jul 2010
    Location
    Great Lakes
    Boat
    Searay
    Details
    350/370 1990 Sundancer
    Engine(s)
    454 Merc with Bravo I drives
    Posts
    5

    3 blade vs 4 blade and rotation info

    I have a 1990 350 Searay Sundancer. I have trouble sometimes with cavitation and overall performance in large waves on Lake Erie. The boat has two bravo one stern drives with three blade ss mirage props, 15.25 x 19. My drives are counter rotating; portside turns LH and starboard turns RH. I had a mercury rep tell me to try to go to ss four blade props and changing the linkage on my motors so my rotation would be opposite; portside would be RH and starboard would be LH. He said they found out on larger boats my side they got better performance. What do you guys think about this and what type of ss prop and what size would I go to. Also, what do you think about this rotation change.

    Thanks,
    Scott

  2. #2
    Join Date
    Oct 2006
    Location
    Jersey Shore
    Boat
    Sea Ray
    Details
    2001 380DA
    Engine(s)
    Merc 8.1S Horizons (2008)...Hurth ZF 63 V-drives...Westerbeke 7.0 BCGD... Raytheon RL80C, Garmn740s
    Posts
    7,585

    Re: 3 blade vs 4 blade and rotation info

    WOW! Never seen a Pre-clinton 350 with outdrives. Cool!
    I have a friend with twin bravo 2 drives on a 2001 maxum 3300. He went to SS three bladers and noticed a HUGE difference in performance compared to the aluminum props. Not sure you're going to need 4 blades, but I do think the change to SS would make a huge difference, without getting into all the changing of rotation stuff.


    _____Day Tripper_____

    Previous boats: 1988 Regal Sebring 19' cuddy; 2002 Crownline 262CR; 1989 Sea Ray 340DB




  3. #3
    Join Date
    Jul 2010
    Location
    Great Lakes
    Boat
    Searay
    Details
    350/370 1990 Sundancer
    Engine(s)
    454 Merc with Bravo I drives
    Posts
    5

    Re: 3 blade vs 4 blade and rotation info

    Yeah they only made 11 with drives. I allready have 3 blade ss props. I am beeing told to go to 4 blade ss props because of cavitation that I get and to give me more trust/power in waves. The rep also sead it would help to change rotation. Just throughing it out there to see what others think and what size and make prop to go with.

  4. #4
    Join Date
    Mar 2007
    Location
    Hudson River
    Boat
    Sea Ray
    Details
    97 330da
    Engine(s)
    7.4 MPI's Bravo 1s Westebeke 4.5
    Posts
    364

    Re: 3 blade vs 4 blade and rotation info

    [QUOTE=Float Funds;374644]I have a 1990 350 Searay Sundancer. I have trouble sometimes with cavitation and overall performance in large waves on Lake Erie. The boat has two bravo one stern drives with three blade ss mirage props, 15.25 x 19. My drives are counter rotating; portside turns LH and starboard turns RH. I had a mercury rep tell me to try to go to ss four blade props and changing the linkage on my motors so my rotation would be opposite; portside would be RH and starboard would be LH. He said they found out on larger boats my side they got better performance. What do you guys think about this and what type of ss prop and what size would I go to. Also, what do you think about this rotation change.



    Had the same issue with ours,I switched the props to mercury Revolution 4s.Cavitation gone,better acceleration and a couple of MPH increase at cruise speed,top end was the same as the 3 blades I took off.I find the merc reps recommendation interesting.I would like to hear how that works out...
    Tom and Linda
    1997 330da Fast Reward
    7.4 MPI's Bravo 1's
    4.5 Westerbeke
    Hudson River NY

  5. #5
    Join Date
    Jul 2010
    Location
    Great Lakes
    Boat
    Searay
    Details
    350/370 1990 Sundancer
    Engine(s)
    454 Merc with Bravo I drives
    Posts
    5

    Re: 3 blade vs 4 blade and rotation info

    Thats the prop I was thinking of using mercury Revolution
    the mrc rep told me to go one pitch lower when I go to a 4 blade and I have now 15.25 X 19 but the revolution is a 14 5/8 X 17 so Idont know what to do.

  6. #6
    Join Date
    Mar 2007
    Location
    Hudson River
    Boat
    Sea Ray
    Details
    97 330da
    Engine(s)
    7.4 MPI's Bravo 1s Westebeke 4.5
    Posts
    364

    Re: 3 blade vs 4 blade and rotation info

    Quote Originally Posted by Float Funds View Post
    Thats the prop I was thinking of using mercury Revolution
    the mrc rep told me to go one pitch lower when I go to a 4 blade and I have now 15.25 X 19 but the revolution is a 14 5/8 X 17 so Idont know what to do.
    Try here...www.propgods.com Good forum.Our original props were Mirage Plus 15.25 x 19 .I went with 14 5/8 x19,which maxed the engine at the same 4500 Rpm.
    Last edited by sr330daguy; 07-19-2010 at 08:45 PM.
    Tom and Linda
    1997 330da Fast Reward
    7.4 MPI's Bravo 1's
    4.5 Westerbeke
    Hudson River NY

  7. #7
    Join Date
    Nov 2006
    Location
    Lake St Clair, MI
    Boat
    Sea Ray
    Details
    400 Sundancer
    Engine(s)
    7.4L Horizons
    Posts
    1,176

    Re: 3 blade vs 4 blade and rotation info

    I never knew they put outdrives on anything that big! Pics?? Pretty cool as it's rare!
    1998 400DA 7.4 Horizons

  8. #8
    Join Date
    Jul 2010
    Location
    Great Lakes
    Boat
    Searay
    Details
    350/370 1990 Sundancer
    Engine(s)
    454 Merc with Bravo I drives
    Posts
    5

    Re: 3 blade vs 4 blade and rotation info

    Heres some pics I can"t find any out of water of drives but in one pic you can see one set of controls. With drives I can get in shalow water with drives, also my top speed is about 40mph.
    Attached Images Attached Images

  9. #9
    Join Date
    Oct 2006
    Location
    Jersey Shore
    Boat
    Sea Ray
    Details
    2001 380DA
    Engine(s)
    Merc 8.1S Horizons (2008)...Hurth ZF 63 V-drives...Westerbeke 7.0 BCGD... Raytheon RL80C, Garmn740s
    Posts
    7,585

    Re: 3 blade vs 4 blade and rotation info

    Float
    Boat looks GREAT! LOVE what you've done with the color scheme. I'm a big fan of the monochromatic treatment. NICE!


    _____Day Tripper_____

    Previous boats: 1988 Regal Sebring 19' cuddy; 2002 Crownline 262CR; 1989 Sea Ray 340DB




  10. #10
    Join Date
    Mar 2008
    Location
    Essex, MD
    Boat
    Sea Ray
    Details
    1994 290 Sundancer
    Engine(s)
    Twin 2005 220hp 4.3 MPI's FWC w/ Alpha 1 Gen IIs
    Posts
    352

    Re: 3 blade vs 4 blade and rotation info

    Outstanding pictures. That 350 looks fantastic, and the pics have great resolution.

    I bet you could throw a party in the bilge of that boat with stern drives. Its really cool that it will hit 40mph.

    In the Merc prop lineup, the only real 4 blade alternative to the Mirage Plus is the Revolution 4. I am also curious to know if switching sides for your engine rotations would make a big difference for you.

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