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How Straight is yours?
By:Marc Anyon
Date: 3/21/1999, 6:23 pm

I've just started to build Nick Shade's Guillemot and can't wait to see the finished Kayak. As I got to rigging the forms on my locally bought 2" x 4" (corkscrew), I thought what a great pity it would be to build a beautiful kayak that only did left handers or for that matter left me sitting decidedly low in a puddle somewhere just below the waterline. I think the sighting of LONG design waterline marks (DWL)is a brilliant way of longitudinal and rotational (about the centre of the strongback)alignment but I thought how nice it would be to be able to laser align the whole thing. It's nice to KNOW that you've got it right! I'd love to hear comments on the idea that I came up with. Chances are that it's all been done before but if it's a goofy idea, others who might "try this at home" need to know. Here goes:

I figured that where you can shine laser light, you can thread a nice piece of string (twine). The problem with sighting the DWL is that it gives you no guidance to lateral alignment, that is, are my forms still on the centre line that I drew.

I know that once I set up my strongback and forms the strongback dried out more and the centreline was about as usefull as a chocolate teapot.In addition to this, it's impossible to sight the vertical form centreline at the top and botttom at the same time.

THE CURE Drill a 3/8" hole on both sides of the form using the gridlines on the graph paper 2" up from the DWL and 2" out from the centreline of the graph paper. You've just excluded any errors in your strongback from affecting your boat. Pass the string through all the holes down one side and anchor it behind form 15 and in front of form 2 using a loop in the line passed through the terminal holes and a 2" nail passed through the loop. Align the string with the centrepoint of the intersection of the horizontal and vertical graph lines passing through the hole on those end forms and then centrally align forms 3 onward with the string. As you check lateral alignment with the string, sight with the DWL to capture longitudinal alignment and use a set square to check wether the form is dead upright against the string. Also use the square against the string to make sure that the form is at right angles to the true centreline as defined by the terminal forms.

I've just done this and I reckon all forms are aligned to within half the thickness of a gridline on the graph.

I chose forms 2 and 15 on the Guillemot as the previous forms, namely 1/2 and 1 are too small and force the string in too close to the strongback. Accuracy with this will increase with distance away from the strongback.

That took a whole lot more explaining than I thought, sorry SYSOP for using lots of space. Any views good or bad welcomed. P.S. You ought to try buying this sort of lumber in the U.K. Oy Veh already and then when you do find it, £140 just for the boards and no "have a nice day"!

Messages In This Thread

How Straight is yours?
Marc Anyon -- 3/21/1999, 6:23 pm
Re: How Straight is yours?
Mike Allen -- 3/22/1999, 8:51 pm
Re: How Straight is yours?
Richard Moynes -- 3/22/1999, 8:20 pm