User Tag List

Page 1 of 3 1 2 3 LastLast
Results 1 to 15 of 37
  1. #1
    Join Date
    Mar 2013
    Location
    Sunshine Coast, Queensland
    Posts
    186
    Thanks (Given)
    0
    Thanks (Received)
    6
    Likes (Given)
    1
    Likes (Received)
    47
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)

    Lower unit leading edge

    Gidday guys, merry Christmas to you all, hopefully 2021 will be a better year than 2020 for everyone

    For a long time now, I have been battling a V-shaped spray coming from my lower unit until I trim out a fair bit. Using the boat for water skiing, this of course
    makes the wake a bit unpleasant for barefooters. I have tried raising my engine, I have experimented with the bottom of the hull, only thing left to try
    is my lower unit leading edge. It's in good shape, just fairly thick. Does anyone actually fair or sharpen the leading edge of their lower to improve the water
    flow over it? The only thing I can think of now, is that being fairly thick it's "pushing" through the water rather than "cutting" through it, causing the spray
    A/V plate is just above the waterline while running

    Anybody offer any advice?

    Click image for larger version. 

Name:	20140507_095727.jpg 
Views:	43 
Size:	389.7 KB 
ID:	479649

  2. #2
    Join Date
    Jun 2018
    Location
    Floating around
    Posts
    3,929
    Thanks (Given)
    464
    Thanks (Received)
    418
    Likes (Given)
    3355
    Likes (Received)
    2447
    Mentioned
    1 Post(s)
    Tagged
    0 Thread(s)
    IVe experienced this spray as a skier it’s not fun at all. I was pretty young but we solved it with a different prop. I didn’t see mention of props
    Hydrostream dreamin

  3. #3
    Join Date
    Mar 2013
    Location
    Sunshine Coast, Queensland
    Posts
    186
    Thanks (Given)
    0
    Thanks (Received)
    6
    Likes (Given)
    1
    Likes (Received)
    47
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    I have tried different props, doesn't really make any difference. It's not coming off the back of the lower (ie prop), but definitely the leading edge.

  4. #4
    Join Date
    Jun 2018
    Location
    Floating around
    Posts
    3,929
    Thanks (Given)
    464
    Thanks (Received)
    418
    Likes (Given)
    3355
    Likes (Received)
    2447
    Mentioned
    1 Post(s)
    Tagged
    0 Thread(s)
    Plenty of guys shape the skeg especially after damage. You have to be careful with it though that’s your boats entire steering control. I can’t see a reason not to file it sharper to try and help this issue. Post a pic or two helps
    Hydrostream dreamin

  5. #5
    Join Date
    Mar 2013
    Location
    Sunshine Coast, Queensland
    Posts
    186
    Thanks (Given)
    0
    Thanks (Received)
    6
    Likes (Given)
    1
    Likes (Received)
    47
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by LakeFever View Post
    Plenty of guys shape the skeg especially after damage. You have to be careful with it though that’s your boats entire steering control. I can’t see a reason not to file it sharper to try and help this issue. Post a pic or two helps
    I reckon it's the leading edge of the lower itself, not the skeg. Away at work at the moment, I will post some photos when I get back in a couple of days

  6. #6
    Join Date
    Feb 2011
    Location
    HUDSON, FLORIDA
    Posts
    1,528
    Thanks (Given)
    427
    Thanks (Received)
    63
    Likes (Given)
    433
    Likes (Received)
    450
    Mentioned
    1 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by wettek View Post
    I reckon it's the leading edge of the lower itself, not the skeg. Away at work at the moment, I will post some photos when I get back in a couple of days
    ITS not the leading edge makin that spray imo. you have someobstructiion dragging somewhere. seen that before. do you have a notched transom?

  7. #7
    Join Date
    Mar 2013
    Location
    Sunshine Coast, Queensland
    Posts
    186
    Thanks (Given)
    0
    Thanks (Received)
    6
    Likes (Given)
    1
    Likes (Received)
    47
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by KIRCHNER View Post
    ITS not the leading edge makin that spray imo. you have some obstruction dragging somewhere. seen that before. do you have a notched transom?
    Unfortunately no, it's not the hull. I have hung over the back and observed a few times, and even tried modifying the bottom of the hull
    temporarily (outboard is on a built in pod/extension, the bottom of which is angled up slightly) by gluing on nylon plates to make the
    hull/pod extension level.

    A couple of photos I have on file, you can't see the leading edge of the A/V plate, but it is about 1/2-3/4" above the water line. Looks like water is coming off the lower unit leading edge
    heading up then the spray deflector shoots it out into a V. Got me buggered what's going on.

    Click image for larger version. 

Name:	20140507_095544.jpg 
Views:	74 
Size:	397.3 KB 
ID:	479683Click image for larger version. 

Name:	20140507_095553.jpg 
Views:	82 
Size:	349.9 KB 
ID:	479684

  8. #8
    Join Date
    Feb 2011
    Location
    HUDSON, FLORIDA
    Posts
    1,528
    Thanks (Given)
    427
    Thanks (Received)
    63
    Likes (Given)
    433
    Likes (Received)
    450
    Mentioned
    1 Post(s)
    Tagged
    0 Thread(s)
    Why cant you see the cav plate if you say its above the water? what i see in the pic, cav plate is submerged. motors set too low always make that v spray. i did some barefooting, i my youmger years, boat spray is like skiing in a rain storm. you say you raised the motor and still have the spray?

  9. #9
    Join Date
    Dec 2017
    Location
    Lake Ashby, New Smyrna Beach FL
    Posts
    1,348
    Thanks (Given)
    159
    Thanks (Received)
    74
    Likes (Given)
    296
    Likes (Received)
    645
    Mentioned
    3 Post(s)
    Tagged
    0 Thread(s)

    Spray culprit

    Do you have one of these?
    Attached Thumbnails Attached Thumbnails skeg.png  
    \\\/// \\\/// \\\/// \\\/// \\\/// \\\/// \\\/// \\\/// \\\/// \\\/// \\\/// \\\/// \\\/// \\\/// \\\/// \\\/// \\\/// \\\/// \\\///


    Checkmate Pulsare 2100 with a 2017 Merc 250 Pro XS

  10. #10
    Join Date
    Dec 2017
    Location
    Lake Ashby, New Smyrna Beach FL
    Posts
    1,348
    Thanks (Given)
    159
    Thanks (Received)
    74
    Likes (Given)
    296
    Likes (Received)
    645
    Mentioned
    3 Post(s)
    Tagged
    0 Thread(s)
    We used to call them the torque tab. Helps negate the lower unit trying to turn. Also can make spray at the right height.
    \\\/// \\\/// \\\/// \\\/// \\\/// \\\/// \\\/// \\\/// \\\/// \\\/// \\\/// \\\/// \\\/// \\\/// \\\/// \\\/// \\\/// \\\/// \\\///


    Checkmate Pulsare 2100 with a 2017 Merc 250 Pro XS

  11. #11
    Join Date
    Mar 2013
    Location
    Sunshine Coast, Queensland
    Posts
    186
    Thanks (Given)
    0
    Thanks (Received)
    6
    Likes (Given)
    1
    Likes (Received)
    47
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by KIRCHNER View Post
    Why cant you see the cav plate if you say its above the water? what i see in the pic, cav plate is submerged. motors set too low always make that v spray. i did some barefooting, i my youmger years, boat spray is like skiing in a rain storm. you say you raised the motor and still have the spray?
    You can't see the cav plate because the water being pushed up by the leading edge is shooting past it obscuring it. It is not running underwater, even with the engine raised far enough that I can put my finger under the A/V plate while running, the spray is still there.
    I reckon it is because the leading edge of my lower is fairly blunt, until I trim out, the leading edge is angled forward and the leading edge is pushing the water up. Once I get past neutral trim, it no longer pushes it up.
    That's why I was asking about trying to fair the leading edge of my lower, so I don't have a flat (albeit narrow) surface ploughing through the water and pushing water up until it hit's the spray deflector, shooting out into a V.
    That's the best theory I can come up with!
    As far as skiing/footing goes, it doesn't spray back very far, but is more of a pain for my observer. I want to raise my engine further just to optimize my performance, just trying to get rid of the V-sprayClick image for larger version. 

Name:	20140507_095727.jpg 
Views:	16 
Size:	389.7 KB 
ID:	479730
    Last edited by wettek; 12-27-2020 at 05:39 PM.

  12. #12
    Join Date
    Mar 2013
    Location
    Sunshine Coast, Queensland
    Posts
    186
    Thanks (Given)
    0
    Thanks (Received)
    6
    Likes (Given)
    1
    Likes (Received)
    47
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by TraceF3 View Post
    Do you have one of these?
    Yep, got a torque tab, but the spray is coming from the front of the lower, not at the back.

  13. #13
    Join Date
    May 2016
    Location
    keys
    Posts
    795
    Thanks (Given)
    31
    Thanks (Received)
    45
    Likes (Given)
    254
    Likes (Received)
    424
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Motor too low.
    ANTI40​It's just an idea.

  14. Likes XstreamVking liked this post
  15. #14
    Join Date
    Mar 2013
    Location
    Sunshine Coast, Queensland
    Posts
    186
    Thanks (Given)
    0
    Thanks (Received)
    6
    Likes (Given)
    1
    Likes (Received)
    47
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by Whaaaaat View Post
    Motor too low.
    Unfortunately, it's not. Like I said, I can stick my finger under the front of the A/V plate while running.

  16. #15
    Join Date
    May 2016
    Location
    keys
    Posts
    795
    Thanks (Given)
    31
    Thanks (Received)
    45
    Likes (Given)
    254
    Likes (Received)
    424
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by wettek View Post
    Unfortunately, it's not. Like I said, I can stick my finger under the front of the A/V plate while running.
    Fail to see the relevance of that. Your motor is too low. Raise it until you loose water pressure then lower it back down 1/2 inch. All the photos you gave show the spray pattern of a motor that's too low.
    ANTI40​It's just an idea.

  17. Likes FORBESAUTO, XstreamVking, KIRCHNER liked this post
Page 1 of 3 1 2 3 LastLast

Similar Threads

  1. Leading edge
    By bigbluechevy454 in forum General Boating Discussion
    Replies: 3
    Last Post: 10-02-2012, 06:22 PM
  2. Thanx Leading Edge
    By Marko in forum General Boating Discussion
    Replies: 2
    Last Post: 06-16-2008, 11:19 AM
  3. thanks leading edge
    By rollin in forum General Boating Discussion
    Replies: 11
    Last Post: 10-04-2007, 09:18 PM
  4. Leading edge cup?
    By Carter Powell in forum Technical Discussion
    Replies: 6
    Last Post: 02-05-2006, 11:06 AM
  5. File leading edge of lower Unit?
    By Dregsz in forum Technical Discussion
    Replies: 2
    Last Post: 06-15-2005, 07:53 AM

Posting Permissions

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