How to Measure Transoms For Boat Swim Platforms

For Platforms we need to know three things:

  1. The length of the platform, which should be 3″ to 6″ (76.2mm to 152.4mm) shorter on each side than the full width of the transom to avoid hard knocks in tight places.
  2. The projection or how far it should go out.
  3. The transom curve or camber to which the platform is to fit. This can be shown as the CAMBER in the length of the platform you want. See “A” & “B” on the drawing below.



Tip: Find a friend! It’s much easier to measure with 4 hands.

Made best on the transom at the height at which you expect to mount the platform. Locate the center of the transom and chalk a vertical line. Take a straight piece of wood, rod, or tubing the same length as the platform you desire. Mark the center of the straight edge, hold it level and square against the transom with the center marks matched. Measure from the ends of the straight edge to the transom. When both measurements are the same, this is the CAMBER figure needed.


The general rule of thumb is that the platform can go as far as (Y), as the bracket goes down the transom (X).

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