Sailing dinghy plans, paper to digital—Newbie needs help


I’m new to SU and have started to learn it through one of the subscription tutorials. What I’d like to achieve is to convert the analog plans for a 12’ John Welsford SCAMP sailing dinghy into digital. I’ve included a photo of one of the bulkheads. Obviously, I require only 2D images, in millimeters.

How can I create an (x,y) coordinate system that allows me to measure from a baseline/centerline? Ideally, an ability to establish an (0,0) origin point that will allow the (x,y) coordinates to appear either next to the cursor or in the measurement box in the bottom right corner as the cursor moves would be very efficient.

Alternatively, is/are there a better way to make this digital conversion?

Thanks for your time.


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Switch to Camera (menu) > Standard Views (submenu) > Top

Then use the ORIGIN (the intersection of the axes) as the intersection of your baseline and centerline.

For the bulkhead (above) you can draw half of it, then copy and flip or mirror it.
(A mirror plugin may make it easier.) To use the built-in “Flip along” commands you need to group the half before the command will appear of the right-click context menu.

After the two half groups are mated correctly, explode both and regroup as one.

@thorviking, drawing this way you can hover over the vertices (and geometry) with the ‘Tape Measure’ tool and it will show X, Y (and Z) values next to the cursor.


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If you are using your scans of the sheets, be aware that things may not line up correctly.

Thanks, Dan, that did the trick. I left out some details that relate to cuts that depend on dimensions that will be determined later (hatch doors, stringer cutouts), but it was a great first attempt.

I think I’ll pursue that plug-in option you mentioned just to see how a mirroring operation differs from a flip operation. I also want to fair that curve at the cabin top. The curve appears to dip down as it meets the centerline and it was more apparent after the copy-flip operation, so creating fair curves is my next effort.

Thanks, again, for your help.


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@g.h.hubers, thanks for your help.


@DaveR, yes, even to a newbie, distortion in scanning (though this was a smartphone photo) or the possibility the paper plans were not accurate/to scale occurred to me.

Thanks for your help.


I got a mirror plug-in and I think it is more straight forward than the flip operation.

Speaking of the Extension Warehouse, what curve plug-in would one recommend to create a fair curve to connect the offset points seen in the attached photo? This is the bottom of the boat and, of course, will require mirroring.

Thanks, again.


Take a look at Bezierspline from Fredo6:

(For all Fredo6 extensions, you must install the ‘library’ as well)


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@MikeWayzovski, thanks for the tip.


Thanks, Mike. The Catmull Spline tool in the Fredo6 collection did great.

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