Results 1 to 21 of 21

Thread: Trailer cleanace question

  1. #1
    Join Date
    Sep 2004
    Location
    Alabama
    Posts
    578

    Default Trailer clearance question

    Bought a trailer and modifying it to fit a 20' inboard. Just added additional bunks and bow supports and very happy with the fit.

    Turned my attention of the back to work on a prop guard when I realized I only have about 7" of clearance. By the time I fab up the guard I would have only about 5" of clearance. That is obviously going to drag constantly.

    I realize that there are many factors and the angle from the wheels to the bottom of the guard is important but anyone have a height that like to maintain that works? Any recommended clearances?

    Obviously I have to raise it up some and do have a couple of options. Just need an idea of how much clearance I do need to shoot for.

    Last edited by Kudzu; 05-19-2021 at 06:58 AM. Reason: typo
    Jeff
    Kudzu Craft Skin boats
    SoF boat kits, supplies and plans

  2. #2
    Join Date
    Oct 2009
    Location
    South Puget Sound/summer Eastern carib./winter
    Posts
    19,558

    Default Re: Trailer cleanace question

    can you lower the ball ?

  3. #3
    Join Date
    Jan 2005
    Location
    Deepest Darkest Wales
    Posts
    23,678

    Default Re: Trailer cleanace question

    How far behind the rearmost tyres is the prop?

    THe clearance angle matters - a lot. - a single low point in line with the tyres could get by with as lillte as 5 inches - .....
    I'd much rather lay in my bunk all freakin day lookin at Youtube videos .

  4. #4
    Join Date
    Mar 2017
    Location
    Indian Land, SC, USA
    Posts
    3,398

    Default Re: Trailer cleanace question

    Any chance you could mount larger diameter tires on the trailer ?


    Rick

  5. #5
    Join Date
    Jun 2010
    Location
    PNW, an island west of Seattle
    Posts
    2,800

    Default Re: Trailer cleanace question

    Remove the prop for transport?

    Jeff

  6. #6
    Join Date
    Jun 2003
    Location
    Central Coast, Ca
    Posts
    30,966

    Default Re: Trailer cleanace question

    It looks like the cross member is slightly lower than the prop, but that may be camera angle. Any evidence of that crossmember hitting the ground?
    I'm thinking if you rotate the prop so there is not "one blade down" it may be fine...



  7. #7
    Join Date
    Aug 2006
    Location
    Rockford, IL
    Posts
    12,156

    Default Re: Trailer cleanace question

    Is that a rudder aft of the prop? What is the clearance there? Fore'n'aft Distance from wheelbase to prop is key, but 7" doesn't look sufficient to me for over the road towing.

  8. #8
    Join Date
    Jul 2000
    Location
    N.E. Connecticut.
    Posts
    7,006

    Default Re: Trailer cleanace question

    Been there, done that with a prop guard. It is intended to protect the prop and rudder. Build it right and donít worry it it drags occasionally. Thatís what it is for. I think your clearance will work. I built one for this boat I had and it worked just fine.
    You can just see it under the boat.
    Attached Images Attached Images

  9. #9
    Join Date
    Apr 2005
    Location
    Hills of Vermont, USA
    Posts
    39,824

    Default Re: Trailer cleanace question

    Quote Originally Posted by wizbang 13 View Post
    can you lower the ball ?
    My first thought. Drop the ball a couple of inches & I bet you'd gain 3 or 4 on the prop/rudder.
    "If it ain't broke, you're not trying." - Red Green

  10. #10
    Join Date
    Mar 2007
    Location
    East Quogue,NY
    Posts
    22,429

    Default Re: Trailer cleanace question

    Commercially made trailers for inboards have a pretty low crossbar. You could maybe call one if you needed an actual measurement. Here's a Load-Rite ( no affiliation)

    DSCN7129-681x338.jpg
    There are two kinds of boaters: those who have run aground, and those who lie about it.

  11. #11
    Join Date
    Jan 2005
    Location
    Deepest Darkest Wales
    Posts
    23,678

    Default Re: Trailer cleanace question

    Four inches + one and a half inches for every foot from the nearest axle.
    I'd much rather lay in my bunk all freakin day lookin at Youtube videos .

  12. #12
    Join Date
    Apr 2005
    Location
    Hills of Vermont, USA
    Posts
    39,824

    Default Re: Trailer cleanace question

    Quote Originally Posted by Breakaway View Post
    Commercially made trailers for inboards have a pretty low crossbar. You could maybe call one if you needed an actual measurement. Here's a Load-Rite ( no affiliation)

    DSCN7129-681x338.jpg
    This trailer would drag on my driveway even if the ball were dragging...
    "If it ain't broke, you're not trying." - Red Green

  13. #13
    Join Date
    Sep 2004
    Location
    Alabama
    Posts
    578

    Default Re: Trailer cleanace question

    Sorry, I posted then got side tracked and forgot about it.

    I measured this with the ball at towing height. 7" is at the prop and rudder. Rudder will probably hit before the prop does since it is further back. But the issue is going to be when you hit an incline of dip in the road. Going down the highway will not be an issue. Backing in my shop I am building might very well be a problem though.

    Quote Originally Posted by P.I. Stazzer-Newt View Post
    Four inches + one and a half inches for every foot from the nearest axle.
    This is what I was asking for! I am well below that and probably will not be able be able to raise it enough to meet that. I am sure I am 3' behind the axle. I will have to measure but a have decided a prop guard is a must! One prop or rudder repair would pay for it.

    I just ordered brackets so I can flip the axle. That should gain me close to 3". I found weld on rollers to mount on the prop guard for when it does hit the pavement. My guess is 8" is going to be best without spending a ton of money.
    Jeff
    Kudzu Craft Skin boats
    SoF boat kits, supplies and plans

  14. #14
    Join Date
    Apr 2005
    Location
    Hills of Vermont, USA
    Posts
    39,824

    Default Re: Trailer cleanace question

    What about Bruce's idea of lowering the hitch - IOW the ball? I'd think that could help quite a bit.
    "If it ain't broke, you're not trying." - Red Green

  15. #15
    Join Date
    Sep 2004
    Location
    Alabama
    Posts
    578

    Default Re: Trailer cleanace question

    Decided an axle flip was a good place to start and an easy way to gain 3" or more clearance. Boy was I wrong on the EASY part. At least for a not so young man with arthritis in his lower back.

    Really not a hard job but just very physical and lots of getting up and down which is what wears me out.

    20210518_123119.jpg

    One axle done and you see how much it gained, Rough measurement is 3.5" taller.

    Still going to build a prop guard cage.
    Jeff
    Kudzu Craft Skin boats
    SoF boat kits, supplies and plans

  16. #16
    Join Date
    Sep 2004
    Location
    Alabama
    Posts
    578

    Default Re: Trailer cleanace question

    Having trouble explaining this but just got the boat back on the trailer. With the hitch at the same height I now have 14" clearance at the prop compared to 7" before.

    Axle flip should have given me 3.5-4" inches but I gained 7"? I have not stood back and looked but the only thing I think of the angle of the trailer changed a lot and kicked up the rear more than I expected. We have steep ramps here so it is not a problem but it sure it higher than I expected.... or really wanted. This is about the height of the original trailer I replaced and it was very hard to get in the boat without a ladder.
    Jeff
    Kudzu Craft Skin boats
    SoF boat kits, supplies and plans

  17. #17
    Join Date
    Apr 2005
    Location
    Hills of Vermont, USA
    Posts
    39,824

    Default Re: Trailer cleanace question

    Quote Originally Posted by Kudzu View Post
    Having trouble explaining this but just got the boat back on the trailer. With the hitch at the same height I now have 14" clearance at the prop compared to 7" before.

    Axle flip should have given me 3.5-4" inches but I gained 7"? I have not stood back and looked but the only thing I think of the angle of the trailer changed a lot and kicked up the rear more than I expected. We have steep ramps here so it is not a problem but it sure it higher than I expected.... or really wanted. This is about the height of the original trailer I replaced and it was very hard to get in the boat without a ladder.
    Sure. You raised it 3.5" in the center, so the trailer pivoted - if the wheels are halfway between the prop & the hitch, that'd give you 7". Picture a see-saw.

    So - what you did had the same net effect as lowering the hitch 3.5" - without ground clearance issues at the hitch.
    "If it ain't broke, you're not trying." - Red Green

  18. #18
    Join Date
    Mar 2007
    Location
    East Quogue,NY
    Posts
    22,429

    Default Re: Trailer cleanace question

    Great news!

    Now, tape your new bridge clearance to your rear-view mirror!

    Kevin
    There are two kinds of boaters: those who have run aground, and those who lie about it.

  19. #19
    Join Date
    Sep 2004
    Location
    Alabama
    Posts
    578

    Default Re: Trailer cleanace question

    The problem with being a old draftsman is you need to see it to paper sometimes to grasp what you did/are doing.

    I slid under the boat with a tape measure and after looking at it a couple of minutes, I realized my mistake. I just measured wrong. I measured from spring pad on the axle to the other side of the spring and should have measured from the center line of the axle to the spring. Makes perfect sense now and I gained 7.5" I wish wasn't quite so high but it better than dragging a prop any day!
    Jeff
    Kudzu Craft Skin boats
    SoF boat kits, supplies and plans

  20. #20
    Join Date
    Oct 2009
    Location
    South Puget Sound/summer Eastern carib./winter
    Posts
    19,558

    Default Re: Trailer cleanace question

    hey if it's too high, try raising the ball

  21. #21
    Join Date
    Sep 2004
    Location
    Alabama
    Posts
    578

    Default Re: Trailer cleanace question

    Quote Originally Posted by P.I. Stazzer-Newt View Post
    Four inches + one and a half inches for every foot from the nearest axle.
    Ended up with 14". Math says 12.5" Build a prop guard and I will be right on the money. Seems tall but as long as I an can launch it that is all that matters.
    Jeff
    Kudzu Craft Skin boats
    SoF boat kits, supplies and plans

Posting Permissions

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