I just finished installing the last of the forms (bow and stern) for an Outer Island to their bases, then rechecked the alignment of all of the forms. I used the Kurt Maurer method of adjustable form-to-base attachment (Thank you Kurt for all the great info on your blog.) When I first installed the forms I measured the distance from the tip of each form to the string line and matched the alignment so that distance equaled the rocker measurement on the form. To recheck the alignment I clamped a small flat scrap board to the centerline of form, with the bottom of each scrap board at the waterline marked on each form (actually to the scrap glued to the form (another KM suggestion), and a mark four inches above the bottom end, aligning each form with that four inch mark at the string line. A few of the forms had to be moved so much that there was no adjustability left in the 3/4" holes drilled in the bases. I then remeasured the distance from the tip of those forms to the string. Two forms have a 1/4" difference between alignment with the waterline mark and the alignment using the rocker value on the forms. (Two others are off by 1/16". That can be just the thickness of the string so I'm not too concerned about those two.)

Am I doing something wrong, or shouldn't the waterline necessarily be at the same distance from the string on every form? The forms were cut accurately. I cut them on a bandsaw a little proud of the line, and sanded just to the line using a disc sander with a guide platform perpendicular to the disc.