Results 1 to 3 of 3

Thread: Weigh your boat on the Trailer

  1. #1
    New Member
    Join Date
    Feb 2009

    Weigh your boat on the Trailer

    Found this site that talks about weighing your boat on the trailor with a bathroom scale.

  2. #2
    New Member
    Join Date
    Feb 2009

    Re: Weigh on Boat on Trailor

    Excuse the subject. Should read "Weigh your boat on the trailor."

  3. #3
    Administrator Papee's Avatar
    Join Date
    Jan 2008

    Re: Weigh your boat on the Trailer

    Fixed it for you. Here's the important parts just in case.

    The boat stays on the trailer the entire time. Put the scale under the tongue near the end. You can even put a block on the scale to lift the tongue so you can see the dial. Record the weight. Now, slide the boat aft on the trailer 12" to 18". You must measure exactly how many inches you moved it, and record that. With the scale in the same location under the tongue, record the new scale reading. Finally, measure the distance in inches between the trailer axle (wheel centerline) and the point on the tongue where it touches the scale. You have then four measurements:

    W1 = first (heavier) scale reading in lbs, W2 = second scale reading in lbs, X = the distance you shifted the boat in inches, C = distance between trailer axle and scale point in inches.

    The formula is Boat Weight = C (W1-W2)/X

    A couple of notes. The result, like any measurement, is sensitive to the accuracy of the input data. In this case, the most critical is the distance you slide the boat. One inch error out of 12 inches will really make a difference in the result. Slide the boat as far as you can and still have a readable load on the scales. Notice, too, that by subtracting the two scale readings, any constant error in the scale is canceled out.

    Note to techies: The formula was derived by taking the sum of the moments around the trailer axle for each case and (since the sum of moments about a stationary object is zero) set the two equations equal to each other and solve for the trailer weight. Things that you don't know, like the trailer's weight and the location of the boat's center of gravity cancel out, leaving just the variables that you can measure, and the boat weight.
    Please check out our YouTube channel and subscribe! Our YouTube Channel helps fund the site. Check it out at


Posting Permissions

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