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Thread: Prop Guard

  1. #1
    Member Stanly's Avatar
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    Default Prop Guard

    Anyone have any experience with these? Know anything about them?

    http://www.propguardmarine.com/how.html
    When the HOGS show up, somethins gonna DIE!!!
    Blood Sport
    32' Custom Wooldridge
    MMSI #: 338181573

  2. #2

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    No experience, but it almost seems isimialr to some of the guards I have seen aroud the high thrust OBs. Firend put one of the metal prop guards on and saw a significant reduuction in performance. I could imagine with this design it could increase performance, but I cant imagine if you strike the prop hard that the platic would hold up. Maybe only saving grace is if it did break it might not do as much prop damabe as a metal one.

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    Max speed of 25mph with the 13" & 14" models seems a little limiting.
    Vance in AK.

    Matthew 6:33
    "But seek first the kingdom of God and His righteousness, and all these things shall be added to you."

  4. #4

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    [QUOTE=Stanly;1408671]Anyone have any experience with these? Know anything about them?

    http://www.propguardmarine.com/how.html[/QUOTE

    Not me...I have a Mac's river runner guard on my little 6 hp but it isn't a full "enclosure" like this product. What would be your usage..lakes, river, salt? Seems like it could be a kelp/debris catcher. Would you be able to dock or beach in case the need arose to clear it?

  5. #5
    Member Stanly's Avatar
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    Vance,

    Can you expand with specifics? Just curious as to what size motor etc...
    When the HOGS show up, somethins gonna DIE!!!
    Blood Sport
    32' Custom Wooldridge
    MMSI #: 338181573

  6. #6
    Member Stanly's Avatar
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    Gary,

    I saw these on JP Marine where I bought our inflatables. I bing'd them and found their web site. Thought it was an interesting concept. I was thinking about getting them for the inflatables and possibly the twin 250 yamahas for the ocean boat...
    When the HOGS show up, somethins gonna DIE!!!
    Blood Sport
    32' Custom Wooldridge
    MMSI #: 338181573

  7. #7

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    Haven't tried that particular one, but we have tried a similar design with a hoop around the prop. After a couple broken drive shafts, we decided to never use them again. On top of the added drag from the guard, if you ended up in a sand/gravel bed, you could get a rock caught between the prop and the guard, stopping the prop immediately. This put a huge amount of torque into the drive shaft and in a couple cases, broke it. We were using them on smaller outboards (15 hp), so can't say for sure how they might work on larger ones.

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    Never used them, but I have to call BS. You can't get both more power and more efficiency at the same time. You might get more water to flow faster through a convergent/divergent nozzle just due to bernouli's principle, but you're not getting more power.

  9. #9

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    Have any of you guys seen these? http://www.premiermarine.us/durajet-propeller.php

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    Quote Originally Posted by Garyak View Post
    Have any of you guys seen these? http://www.premiermarine.us/durajet-propeller.php
    That is a convergent/divergent nozzle. Same as used on a jet engine. Uses Bernoulli's principle to create high pressure on the prop side and low pressure on the water side, which creates more flow.

  11. #11

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    They only go up to 70 hp so would be too small for Stanly. Hope he doesn't mind me venturing off into the weeds with this. My skiff is flat bottomed and at higher power settings there is considerable "P" factor even with max adjustment on the lower unit trim tab. Let go of the wheel...instant hard bank to starboard! Wondering if a Dura-Jet unit might improve that situation.

  12. #12

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    Quote Originally Posted by Garyak View Post
    They only go up to 70 hp so would be too small for Stanly. Hope he doesn't mind me venturing off into the weeds with this. My skiff is flat bottomed and at higher power settings there is considerable "P" factor even with max adjustment on the lower unit trim tab. Let go of the wheel...instant hard bank to starboard! Wondering if a Dura-Jet unit might improve that situation.
    I don't know about your motor specifically, but the ones I am familiar with have a way of tightening the turning movement so it doesn't turn too freely. If set with no resistance, just the torque on the prop/engine/etc will cause the motor to try to rotate to one side. You have to stiffen up the turning movement so it takes your added effort to turn it and so it won't turn by itself. For the motor I run, I tend to tighten it up a little more than normal because I like to feel okay with taking my hand off the tiller for a few seconds to put on/take off gloves and not worry about the motor kicking to the side and rolling the boat.

  13. #13

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    Thanks for the tip, anchskier. I'll be checking it out!

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    Quote Originally Posted by Stanly View Post
    Vance,

    Can you expand with specifics? Just curious as to what size motor etc...
    Their site says that's the max speed currently recommended with that size guards.
    Vance in AK.

    Matthew 6:33
    "But seek first the kingdom of God and His righteousness, and all these things shall be added to you."

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    Member Akgramps's Avatar
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    I just emailed one of the references listed on PG's site, the response was rather negative for 60hp or larger.

    That is of course one persons experience, but good enough for me.

    no free rides, sure sounded good
    “Nothing worth doing is easy”
    TR

  16. #16

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    Got one on our 30 HP kicker motor. Bought it specifically to prevent cut lines when trolling. Our unit came from the dealer in Anacortes, WA. They are pricey but worth it if U troll much. For our Merc engine we had to modify the unit so the water intakes did not get completly covered up when it was attached.

  17. #17
    Member Stanly's Avatar
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    Sounds like a no-go for the bigger motors. Might try it on the 9.9 Kicker...
    When the HOGS show up, somethins gonna DIE!!!
    Blood Sport
    32' Custom Wooldridge
    MMSI #: 338181573

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    Default

    We've looked into the prop guards from MPT, http://www.mptmfg.com/ for our 225's.

    A bit spendy, but made for the bigger motors.

    A cheaper alternative would be http://www.propguard.net/measure.html

  19. #19
    Member Ellamar's Avatar
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    From the MPT website:
    Multiple Nozzle Venturi System
    "Each “Multiple Nozzle” assembly consists of two or more hydro-dynamically shaped nozzles with “Venturi” ports between the nozzles that draft outside ambient water to the propeller. A directional column of propeller thrust is created that substantially improves the operating performance, maneuverability and stability of any vessel equipped with the System. Stern lift and dramatic rudder control are generated with the Thrustor®. ©

    The Venturi action that is created by the multiple nozzle system adds water and atmospheric pressure to the column formed by the nozzles, reducing propeller cavitation and increasing the gallons per minute discharge, adding to forward thrust, via the kinetic discharge and hydrofoil acceleration. ©"

    What he said...

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