Establishing the sheer line on borrowed forms

[Curtis Hale]

I am just beginning work on my first Prospector using some borrowed station molds. I have set them on the strongback, have plumbed them, made the stems and am ready to begin milling my cedar. The question I have- having never lofted the plans from the tables in Canoecraft, nor having had a full set of drawings for the canoe- is where is the sheer line on each station so I can lay the first strip? For example, I see on page 54 of the revised edition of Canoecraft, in the table of heights, that Station 0 (center) the has a Sheer of 0-10-4+ (my understanding is this means 10 and 9/16"), is this the number from the TOP of the station mold as is sits on the strongback? AND, if so, should I be adding a 1/4 inch (essentially pulling my tape off the 1/4" batten I have installed, and measuring down 10 1/2"+)? OR, am I completely missing it and that 0-10-4+ is measured UP from the top of the strongback?? Sorry if my question is confusing, but I am confused as to how to read these tables in Canoecraft and any help would be much appreciated!
Curtis

[Larry in Champaign]

Measure up from the strongback to the highest point (the keel) on each form and verify that this matches the values given for that stations profile. If these match, then measure up from the strongback to establish the sheer. This is the top of the sheer once the canoe is right side up. Strip up from this line as you see fit. In my opinion, following the sheerline for your first strip on the Prospector won't look as good as a more natural, slight upsweep. Look at what others have done and go with what you like.

Larry

[Curtis Hale]

Larry,
Thank you for the clarification. It helps a lot. I am not sure I have the Prospector forms in my shop now as the numbers don't quite line up with those in Canoecraft. For example- the profile of Station 0 in my shop, when measuring up from the strongback top to the keel is 24 3/16", but in the profile in Canoecraft I see it should be 25 1/16". When I measure out from the center of station 0 to the furthest point on the station (where I suppose the sheer line is intended for this station) I get 16 15/16", a number I don't find in any of the tables in Canoecraft. I hadn't planned on trying to use a single strip for the whole sheer, as I agree it looks best to backfill, but still need to know where the top of the canoe is ultimately... One other thing I was thinking of is to simply take the depth stated in Canoecraft (13 1/4), and pull that off the keel at station 0- then project a right angle from the center of the station to establish at least that sheer point. Not sure if the depth is measured from station 0 though...

All in all, the set up looks great- the lines are beautiful and even if this isn't really "the Prospector" it's certainly a nice canoe. Its strange that the maker of the forms labeled all of them as the Prospector though if the numbers are so far off. Is there perhaps other versions or editions of plans for this canoe?

Thanks so much for the help.
Curtis

[Woodchuck]

Have you considered the thickness of the strips? Depending on who made the forms or where you got them, they could be up to 1/2" difference for a 1/4" thick strip canoe. Small differneces in these numbers can really change the way a canoe handles. IMHO NOW IS THE TIME TO CHECK AND DOUBLE CHECK.....

[Larry in Champaign]

Measure the distance from the strongback to the keel on ALL of the forms and compare with the profile figures. Are they ALL off by the same amount? If so, just modify the sheer distance UP from the strongback by the difference (subtract 7/8").

The width of the shear should be 16 15/16" for station 0 (measured 10 9/16" up from the strongback), but the maximum width should be 17 1/4". The fellow who built the forms might have incorrectly subtracted 1/4" for the strips. If they are all like this, just use them as is.

Larry

[sedges]

If the forms were used to build a hull using staples you can use the staple holes in the form edges to judge the sheer. I would put a batten or very good strip on just below the holes and move until you have a nice fair curve. Mark at the top of the strip. Do this on one side then transfer measurements to the other side.

[willo]

The numbers you mention seem to match closer with the ranger , which is also a prospector model , is it 15 or 16 feet long ?

[AsaBlanchard]

Curtis,
I suppose three days after your post, you have already attached the sheer where you wanted to, unless you are like me and waited until you knew you had it right.

Attach the sheer at station 0, 1, 2, 3 on each side, at the same time, squeeze the two planks together at the stem on each end, and put them where it feels natural. You will know the right spot when you hit it.

Don't sweat the small stuff and enjoy your build. I don't think you will do it wrong. You'll know it's right when you go to sleep. If your still awake in the morning, you might want to check the book again.

Asa,
Prospector on the bench

[Curtis Hale]

I finally got a hold of the original builder of the forms! I've got it figured out now- he had blocked each station up 7/8" in order to make it easier to shape the stems, essentially keeping them a touch up from the strongback. I've now done the same and all the measurements line up. One thing I've noticed now though, is that station 5 doesn't appear to have the same type of tumblehome as the other stations. Is this station perhaps not the correct profile?

Thanks to all of you for your help. I am so grateful for this forum!
Curtis