Results 1 to 9 of 9

Thread: Duo Prop questions

  1. #1
    New member
    Join Date
    Aug 2010
    Posts
    5

    Default Duo Prop questions

    I have a 26 foot Olympic with a 5.7 Volvo Penta Dual Prop Outdrive. It presently has stainless F-4 props. I have the opportunity to purchase a set of F-6s. Would this be too aggressive and what perfomance changes might I see with this change?
    Bob

  2. #2
    Member NewMoon's Avatar
    Join Date
    Feb 2008
    Location
    Holladay, UT
    Posts
    126

    Default

    Depends on what RPM you achieve at WOT with a full load now. If you add so much pitch (2 steps is a lot) that you can no longer reach the recommended WOT RPM range for your engine, it will be hard on it.
    Richard Cook
    New Moon (Bounty 257)
    "Cruising in a Big Way"

  3. #3
    Sponsor potbuilder's Avatar
    Join Date
    Apr 2006
    Location
    Palmer
    Posts
    4,229

    Default

    I think the only thing those props will get is is closer to a new or rebuild outdrive or engine rebuild sooner! If i remember correctly you lose/pick up aprox 200rpm's with each step in prop size. If your getting full WOT under load with the props you have i'd stay right there. I'm giving you this advise from 20 years of trying to make duoprops not blow up, my last unit had just under 11,000 hours on it when i sold the boat. If you need somebody good & honest to work on your drive pm me, he was the only guy that ever touched my drives and thats why it lasted so long.

    Alaska Shrimp Pots

    Rigid & Folding Shrimp & Crab Pots
    Electra Dyne Pot Haulers
    Ropes, Buoys, Bait
    alaskashrimppots.com
    akshrimppots@mtaonline.net
    907 775 1692

  4. #4
    Member
    Join Date
    Apr 2006
    Location
    Anchorage and Seward
    Posts
    505

    Default

    Depends on your reduction. Potbuilder's 200 rpm change per prop set number may be based on a diesel. The 5.7 Gi gsser I had would see a 500-600 rpm reduction in WOT by jumping up two steps. You don't want to over prop or you'll be lugging the engine and reducing serice life.

  5. #5
    Sponsor potbuilder's Avatar
    Join Date
    Apr 2006
    Location
    Palmer
    Posts
    4,229

    Default

    Quote Originally Posted by Fish Witch View Post
    Depends on your reduction. Potbuilder's 200 rpm change per prop set number may be based on a diesel. The 5.7 Gi gsser I had would see a 500-600 rpm reduction in WOT by jumping up two steps. You don't want to over prop or you'll be lugging the engine and reducing serice life.
    Yup it was for a diesel & diesel props are each 4 blade where the gasser props are 3 & 4 blade so i can see where you'd get a bit more rpms. I ended up running stainless gasser props, think it was a set of C4's, on my diesel the rpms came in just perfect for my boat right between a set of aluminum A4's & A5's.

    Alaska Shrimp Pots

    Rigid & Folding Shrimp & Crab Pots
    Electra Dyne Pot Haulers
    Ropes, Buoys, Bait
    alaskashrimppots.com
    akshrimppots@mtaonline.net
    907 775 1692

  6. #6
    New member
    Join Date
    Aug 2010
    Posts
    5

    Default

    Forgive my ignorance but what rpms should I be getting at WOT for the 5.7?
    Bob

  7. #7
    Member ocnfish's Avatar
    Join Date
    Oct 2007
    Location
    Alaska
    Posts
    542

    Default

    I have a 2003 volvo penta 5.7 Gi and a duoprop outdrive manuals say 4400 to 4800 rpm. I had stainless steel f4's and was overproped, only got up to just a bit over 4000 rpm and after a few years burnned the valves. Jerry at SHIP in Seward helped me through this one and we put on f3's and rpms jumpped to about 4500 max and 42 mph. More realistic cruise is 3600 rpm and 30 mph. Engine appears to be happy and fuel burn is way better.

    On a lighter boat you could go with a more agressive pitch f5 or f7? it just depends, I think my at sea weight with four fishermen full fuel and all of our stuff is over 8,000 lbs. Main thing is to achieve the rpm range stated in the tech specs of the owner manual.

    I have a question .... where in Anchorage can I take the props to have a few dings strightened out?

  8. #8
    Member spoiled one's Avatar
    Join Date
    Apr 2006
    Location
    Anchorage
    Posts
    3,230

    Default

    Quote Originally Posted by ocnfish View Post
    I have a question .... where in Anchorage can I take the props to have a few dings strightened out?
    I have used A-1 before with standard, stainless props. Not sure if duoprops need to be treated different.

    A-1 Propeller & Impeller Repair




    (907) 344-7767
    210 E Potter Dr
    Anchorage, AK 99518
    Spending my kids' inheritance with them, one adventure at a time.

  9. #9
    aion12
    Guest

    Default

    The original game is hosted by MGame in Korea,
    and requires players to enter their Korean resident registration numbers to register.
    Knight Noah
    There are two other official versions: Knight Online Xross (usually called "JPKO") is hosted in Japan, while Knight Online World is hosted in the United States
    .Knight GoldSome people refer to Knight Online World as USKO. Knight Online Noah
    Both of these versions accept registration from any location. The Knight Online World version is popular in Turkey, and players from this country are an overwhelming majority in that version,
    which means it's hard to find a player speaking another language. Knight Online is officially free-to-play (although to connect to the utmost of the servers during prime time, paid premium is required), but there are some features that must be paid for.
    knight online goldIn addition, there is an in-game Powerup Shop or Store which contains various items that one can purchase such as premium packages. Paid services include exclusive items and Premiums which are a limited-time subscription providing many benefits

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •