Hydrofoil/compression plate/cavitation plate?

Discussion in 'Boats, Blinds, & Gadgets Forum' started by StumpJumper, Mar 8, 2018.

  1. StumpJumper

    StumpJumper Refuge Member

    Nov 23, 2008
    Do any of you run one?

    I have a 15' flat bottom (no tunnel) with float pods/sponsons, 25 hp Yamaha four stroke, and a trim unit that doubles as a jack plate. I'm wanting to get the motor as high as possible and was wondering if a plate would help. Any suggestions?
  2. chuam

    chuam Elite Refuge Member

    Oct 27, 2006
    Get a permatrim. http://www.permatrims.com/

    Best plate out there. It's on the majority of saltwater fishing boats out here. We were going to add one to our duck boat with pods but I ended up selling the boat when I got into a club.
  3. CA Hunter

    CA Hunter Senior Refuge Member

    Sep 5, 2016
    San Jose
    Made one myself. Could get the motor 5" higher. easier gets on plane with three 250LB boys and fishing equipment. Runs around 30MPH with three of us, me alone i'm afraid to try
  4. Tuleman

    Tuleman Elite Refuge Member

    Feb 5, 2005
    Central Kansas
    I've had a custom-made "ride plate" (hydrofoil) on my 12' marsh boat since 1992. During that time, I've had 20hp, 25hp, and 15hp outboards on it and I wouldn't be without it.
    I can think of no downsides to running one, only upsides. While I doubt it let me raise the motor 5", there's no doubt that it lets me run the motor as high as possible. It may give another 1/2" max, but since I've never run the current hull/motor combination without one, I have nothing to compare to. If all you are looking for from the plate is the ability to raise the motor significantly, you'll probably be disappointed; the plate's advantages lie elsewhere.
  5. calling4life

    calling4life Elite Refuge Member

    Feb 10, 2009
    If you're wanting the motor to go as high as possible, you need a purpose built plate for that. For example, the normal whale tale doesn't really have sides that come down, it's essentially flat, which is good for getting on plane and for helping with porpoising, but obviously doesn't hold the water around the lower unit/prop as well as say a compression plate.
    A compression plate, like I have, like tunnel guys run, is essentially a tunnel mounted on your cav plate, it has sides, it is meant to grab and hold all the water shooting out of the back of your boat and keep it around that prop/lower unit so they can be run as high as possible without losing water pressure and grip.

    But, if you run that outboard with that compression plate below the water, you're going nowhere, whereas a whaletail will certainly create more drag, but will still work.
    So, you said running your motor as high as possible, that means you will run the risk of losing water pressure, meaning you need help with that, meaning you want to look at something like a boatright, or Trans sports boats (what I have), compression plate. You need something with sides that pulls/keeps all the water possible around that lower unit/prop.

    But also, plan on having to find a prop that will run surface piercing, IE, you need a lot of cup in the prop. It doesn't matter how high you can lift the motor if your prop doesn't hold...

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