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Cavitation vs ventilation

tcough3475 Member Posts: 5

I'm a fairly new owner of a 2012 188 OB and have been experiencing an issue when out in mildely choppy water.  I loss speed and the engine is running fine.  With some research, I understand that the prop is sucking air and not digging in, which is ventilating, not cavitating.  Besides slowing way down, is there another way to overcome this?  Would lowering the moter help?  I've only got one set of mounting holes showing before I would need to relocate the mount.

Thanks for any help.


  • Capt_Steve
    Capt_Steve Member Posts: 416 admin
    @tcough3475 ... here's the response from Terri in Hurricane Customer Support: 

    This should be mounted in the second hole from the top. 
  • CaptMike2
    CaptMike2 Member Posts: 16 ✭✭
    If it is mounted wrong, I've heard that SS Prop would work also... Capt Steve do you agree? or would Dol-phins work better???

    A Pirate 200 years too late, the canons don't thunder there is nothing to plunder, I'm an over 50 victim of fate..
  • aaa1950
    aaa1950 Member Posts: 19
    I also have a 2012 188 SD Sport with a 115 Yamaha OB. I have the same type problem. One minute I'm running smooth and then all of a sudden the motor starts ventilating. After experimenting, the only way I found to stop it is to trim down significantly, I mean almost completely down. I read that the motor mount should have the bolt in the second slot after purchasing it, but the dealer says it's correctly mounted. My motor mount is all the way down on the transom with the bolt in the top hole. Does this sound right. I could attach a picture if someone tells me how to do it, or I can email a photo. I also would like to solve this problem.
  • Capt_Steve
    Capt_Steve Member Posts: 416 admin
    You know, I've never been able to tell much of a difference with the Doelfin (or any other hydrofoil) ... especially on the modified V-hull of a deck boat. To be honest, the situation noted above may be better served by a self-actuating tab system like Smart Tabs or Bennett.
  • tcough3475
    tcough3475 Member Posts: 5

    hydrofoil.  Says it will reduce ventilation so we'll see.  No drill application so I could take it off without leaving holes if it doesn't perform.  Will let you know how it works out. 

  • tcough3475
    tcough3475 Member Posts: 5
    Going to try thenewSE400 hydrofoil.  Says it will reduce ventilation so we'll see.  No drill application so I could take it off without leaving holes if it doesn't perform.  Will let you know how it works out. 
  • FlyingV5
    FlyingV5 Member Posts: 154 ✭✭✭
    I think you are on the right track, tcough3475. A similar problem on a 16 1/2' deckboat once led me to install a hydrofoil. I predict it will solve your ventilation problem, take a couple mph off the top end and make it steer like it is on rails. Go for it.
  • tcough3475
    tcough3475 Member Posts: 5

    OK, installed the SE 400 hydrofoil and took it out to see what difference(s) it made.  All I can say is, like my boat, I wish I would have done this sooner.  Quick background: I have the 188 Sundeck with the 115 Yamaha and typically it's just my wife and I out on the water.  When making tight turns at moderate speed or when boating through rough/choppy water, I would get air (ventilation) in the prop.  This would require me to shut down to idle and wait until the water became calm around the prop or in the case of choppy water, slow WAY down to prevent it. 

    Installed the SE 400 and took it out last night.  The St Johns River flows through Lake Monroe in Sanford, Florida, and it was breezy.  This created about a 1 foot high white cap condition on the lake but the protected river had minimal waves.

    What a difference!  On the lake, I was able to run full throttle into the white caps without any ventilation.  The ride was much smoother and the bow did not rise out of the water nearly as much as before when coming up on plane.  Not sure how much difference it made in time to get on plane, but no complaints here.  On the river, I tried turning at different speeds and found that the ventilation didn't occur at moderate speed but came back at higher speeds.  But when I backed off the throttle from high speed, it quickly recovered from the ventilation.

    I don't know how it is going to affect top end but the fastest I've been able to get the boat on glass water conditions was about 36 mph (gps speed).  With the SE 400 on the light waves, I was able to get to 37 mph with a little trimming.  No noticeable difference in steering at speed, but wasn't really checking for any changes.

    I'm not connected to the manufacturer of the SE 400, so my post is unbiased.  If you're experiencing this problem, I highly recommend getting this hydrofoil  I picked mine up at Bass Pro Shops for $79 and Overtons has it on sale right now for $74.  It was super easy to install and here's a link to a YouTube video on installing it: