Lofting in color

[B. Parkes]

I'm in the process of lofting a Gartside design. I've been using a sharp pencil but it occurred to me that this might be smudged. I'm thinking of using either a felt tip pen or ball point. I'll use different colors for the waterlines, frames, buttocks and diagonals. Has anyone had any experience with using different colored pens?

[dmg]

I lofted a 28 foot runabout this past fall using 3 colors.

Body lines in black, station/frames in red, and all the waterlines ( 4 ) in blue.

I used Sharpie fine tip. Did markers because I used Kodak photo paper for the whole drawing, and pencils didn't quite work very well because of the gloss finish of the paper. Although they were, in my case somewhat erasable, in your situation, the same idea in pencil might be better.

I used a laser because of the length of the drawing to layout the grid work. When actually cutting the parts, because of the width of the marker's lines, I always measured everything to the center of every line.

You may still want to pencil in everything as you go, and ink them after you are sure all is well.

Dave

[mcdenny]

Eraseability is important.

[B. Parkes]

How did you use a laser for lofting? I never thought of that...it's sounds pretty clever.

[Bob Cleek]

Using a laser for lofting isn't the smartest idea unless you have a very accurate and very expensive laser. If you check the specs on most of the laser levels and such priced under $1000, I think you will find that they are accurate to +/- 1/4" in 50 feet or so. Since such errors have a habit of multiplying when lofting, you would do a lot better using standard lofting practices and the usual care.

[Bob Perkins]

I think the laser would be a great way to mark lines in the grid when your straight edge is not 20 feet long. If you mark the end points and connect them with the laser - it is a quick way to be able to mark a few sets of middle points to use with the straight edge.

We used colored pencils in the lofting class at WBS, but after all of the adjustments were made to the drawings. The colored pencils were used to highlight labels of lines, etc.

We used sharpies for the grids noting stations, water lines, buttocks, etc..

[dmg]

Actually, nothing I could do in a pretty decent shop would give greater accuracy. The degree of accuracy would be a combination of two things, the precision of the rotating head, and the distance you have to project the beam ( longer distances create a wider beam ).

I do not recall exactly what the rating was for mine, but dividing the +- by 4 or 5 seemed pretty tight to me.

At any rate, with part of the shop floor covered with 3/4 CDX, and that covered with the Kodak paper, I just established the baseline down one edge ( with the laser ), tacked a batten here to give me something to bump the tape to. From the batten strip, on both ends of the lofting surface ( 32 ft. long ), I just measured up for all the waterlines. Adjusting the laser to hit both these points is easy once you figure out that a VERY small directional change on the laser could easily be an 1" on/off your marks. Also works much better shop lights off and just enough outside light to see your marks.

Starting at the stem and working aft, all the station/frame positions were marked out, and extended up 8 ft. ( no laser for this ), just 3-4-5 rule to plumb to baseline.

With the rotating laser on my camera tripod, set at about 6 ft ht., the beam projected was about 5/32" at either end of the grid. As mentioned before, I centered any and all layout/lofting points consistently in the center of these 5/32" beam lines.

Laser was a Sears Craftsman, rotating, in a kit. Seems like about $ 125.00 ?

Had the whole grid layed out and color marked in about 1 1/2 hrs.

Will also use to mark the waterline on the hull.

Dave

[boatbear]

I lofted with pencil - nice skinny erasible lines - then used hair spray to fix lines I was completely happy with. I labelled with coloured markers.