Lofting lines

dumbquestionsguy

Name says it all, people.
What would one suggest is the best way to loft lines from an existing boat? (Is this the correct term? I'm meaning essentially measuring and reproducing on paper the shape of a physical boat). From the interior so you're essentially measuring what will be the form? Exterior? Get points and use a batten? That strange cardboard cutout process? Thanks for your patience, and indulgence...
 
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There are a number of ways to do it, and which way you choose may depend somewhat on what type of construction the original canoe is (for example, you'll measure a lapstrake canoe in an entirely different manner than a smooth hull like a canvas canoe). If you can find a copy of "Boats: A Manual for thier Documentation" by Lipke et al., that is the bible on the subject. Regrettably, it is out of print.

For a canvas covered canoe, it is probably easier to take lines on the outside (that's what I do). If you work on the inside, you have the added challenge of locating stations around ribs. Assuming the canoe is symettrical, choose your best quarter. Establish a baseline and level line. Cut out some plywood templates roughly in the shape of the hull, and support it over the hull directly on your station line. Fasten some pointers made from thin stock that touch the hull around its circumference. Lift it off and lay it on your lofting board, positioning it relative to the base and level lines. Transfer your points, spring a batten through them and draw your station.

Once you've got your body stations, and the stem profile on the profile drawing, pick your points off the station view and loft the remaining three views as usual.

Piece of cake... ;)
 
Lofting

The book "Canoecraft " by Ted Moores & Marilyn Mohr has a description of this process, as outlined above. You can get the book at the WCHA store:

http://woodencanoe.org/catalog/prod...d=414&osCsid=79d2f034b40ddd86ec780ac7fe4c9c0c

I've toyed with the process, but never took all the lines off a boat & then built from my lofting work. It doesn't seem too terribly difficult, but I got the impression that the importance of taking your time & being meticulous probably cannot be overstated. Kind of like boatbuilding...:)
 
I use this setup. It works quite well. Its a whole bunch of pointy cedar sticks stapled to a curved board which in turn is held in place on a stand.

Set the canoe up level lengthwise and crosswise. Strike a centerline along the canoe and set a taught string level above it. Establish the mid station, square to the centerline and plumb to the floor, as well as all the other stations at the desired interval. If you don't want to muck up the paint, use low tack masking tape, otherwise a pencil or felt pen.

Now you need to do a bunch of measuring and drawing/drafting, including the distance from the bottom of the canoe to the string, and the width of the canoe below the gunnel at each station.

Use the jig to establish the curve at each station, and then connect the centerline point and the gunnel point on our drafting paper. Do the same for the stem.

Now take your raw data and loft away.
 

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