Cut out my 5’3" fish lines drawn w/ 1/2 board paper template. After cleaning up the outline (all hand tools–surform) it just seemed slightly wrong… Measured and found I’d somehow lost 1/4 inch of width in the middle but that wasn’t it… Finally got smart and measured width found center line at two points and drew it in w/ a straight edge and found that somehow the nose was “off center” by about 3/16 inch whicn gave the whole front end that off look. All fixed.
Moral is if you don’t have the eagle eye, keep a center line drawn on the blank for reference. Everything then makes much more “sense” to the senses!
I just trace the template all the way around, incl. the straight line at the center.
i use a chalk line and snap a center line on all my boards as i am putting the template on. really good idea on parabolic blanks
Yes, snap a chalk line. Use full templates, measure every 12 in for accuracy. Thats the easy part, wait till you put the fin in. Even harder when doing a parabolic system, you have 3 variables to keep track of…center line, stringers through boxes, fins set from edge…fun
I print out half templates because full templates require more pages to be taped together leading to more work and culmative error. And even full templates are too limp to trust if they are paper printouts. I’ve used chalk lines in the past but found that the chalk line isn’t that accurate in the middle either, mainly due to the nose rocker. It turns out to be more of a great circle arc than a straight line. The best thing to do is use a laser level and pin/tape your paper to the blank (or masonite if you’re creating a permanent template from a CAD printout) every foot or 18". When you draw your rail outline also draw your stringer line. You can put your laser level away after that, but it comes in handy again when it’s time to put the fins on since your stringer line will have been planed/sanded away by then. They aren’t very expensive and are useful for lots of other things too.
The full template meaning…half a board tip to tail., that’s what was meant by a full template, sorry for the confusion. Also all full templates should be made out of 1/8 masonite. Only use paper for the trace on to the masonite. Paper templates are useless for accuracy.
You can also use the factory edge of the masonite as a straight edge to get your center stringer line. I have a 12 ft straight edge that I use as a guide to cut all my full templates with. Once I have a clean straight edge, the center line is irrelevant. I can flip the template back and forth to get the perfect center line everytime.
Yeah, full 1/2 board template. 100% of one side from the “stringer” line. Paper do suck for that. No worries about the fins though. Twin keels mounted parallel and perpendicular; no toe no cant. Hopefully I can get that on the first try…heh-heh. Reminds me of a nightmare single fin job in about 1968 that involved late night and clouds of smoke and 4 pairs of eyes and hands. Needless to say it was quite an involved process that didn’t work out too well. That one required a grinder and glass and resin and roving to fix.
“Paper templates are useless for accuracy.”
Agreed. Truing with mini-planes and sanding blocks just doesn’t seem to work very well on paper. A hard template also gives you a much nicer edge to run your pencil around.
Actually I got a really nice, clean line on paper. It’s when you run the pencil along the edge that you run into trouble. Maybe I should have starched it first. Or laid the template on top of waxed paper and painted it w/ resin… or maybe I just shoulda got some masonite or door skin or something…
Long before I met Resinhead I learned the same type of thought process. If you get a chance to meet him he’s a great guy with lots of good ideas. You can buy a sheet of masionite at Lowes for less than $10. Have the guy cut it into four pieces with the panel saw. Now you can make four templates with one edge perfectly straight. I don’t do computer design but I like the concept. My Speed Egg template is a 7’6" but that template has been used for four different boards from 6’11" to 7’10". I just move the template around to make the desired curve. I also have lots of marks on both sides of the template so I can match up both sides of the board. You can snap a line or you can just use the straight edge from the template to get that center line.
Measure twice , cut…
Ray
Slight confusion here…
Full templet= (plain shape) total outline of board.
1/2 templet= just that, half of the total outline from the center of the stringer to the rails on one side.
Spin templet= Nose to just past the centerline and the tail to just past the centerline combined on one shorter piece of templet stock. No straight edge to line up with stringer. Nose on one side and tail on the other. Imagine a big French curve.