Help needed with plank construction

[DNewbie]

Hey all,
I’m currently in the throes of building a DN and need some help. I have no ice boating experience whatsoever and currently am not in contact with any members of the iceboating community. My only resource for information has been what I can glean off the ‘net. I’m a fairly competent builder of small wooden boats such as kayaks, rowing shells, etc. I’ve discovered that I really like building from well thought out plans, not having the time, patience or resources to experiment with my own ideas. I’ve just completed a hull using Paul Goodwin’s hull plans, which are excellent, and am now ready to build a plank but don’t have a firm plan for going about this. I’ve got a set of Gougeon’s 1986 plans and also the IDNIYRA’s ’91 plans. Given the dates of these, I’m wondering if the specifications are still considered appropriate.

Gougeon’s plans call for a hollow plank and have a table of offsets that produce an elliptical shape with a flat section in the middle for the hull to rest on. Hollow planks seem to have fallen out of favor but I’m wondering if the table of offsets is still valid for solid plank construction.

IDNIYRa’s plans call for solid construction but are very limited in detail. The plans merely state that the plank should be built to a “natural curve” with a height of 3” at the center with no clue how this should be accomplished. I’d imagine this means building a jig using an arc of a circle to determine the stations but I’m not sure.

So, does anyone know of any current plans that would provide stations, offsets, lamination schedules, etc.? I already have lams milled and ready to glue. I’ve got two outer skins of white ash measuring  7 ¼ by 5/16ths and two core layers of  5/16th sitka spruce for a total thickness of  1 and ¼ inches. From what I can tell current thinking seems to favor soft planks. I weigh 200lbs and will be making a wooden mast using the IDNIYRA’s plans. Is 1 and ¼ inch thickness appropriate for these parameters?

If anyone can post information about current thinking on plank construction or point me in the right direction, I would be very appreciative. I also realize I might overthinking this whole thing and should just make a plank using TLAR engineering (That Looks About Right) and tune it as needed. However, getting something right the first time is a joy so I’m hoping someone smarter than me can help me out.

[Geoff Sobering]

Have you seen the Plank section of the archives here?
   http://dnamerica.org/archive/Wisdom_web.htm#_Plank_construction
There's quite a good bit of information there.

Paul Goodwin has an Excel spreadsheet that's helpful in designing the plank stiffness:
   http://idniyra.org.hosting.domaindirect.com/articles/plank_design.htm

I think most people have solid three-part planks; generally with Ash skins and something light and cheap for a core (ex. Basswood).  They are certainly very easy to build compared with hollow planks.

Paul Goodwin once posted a description of the spacers he uses to form the crown in his planks, but for the life of me I can't seem to find it now...

Cheers,

Geoff S.
US-5156

[DNewbie]

Geoff,
Thanks for the quick reply. I have read the information in the Collected Wisdom and learned a great deal, which is always fun. However, I can't quite extract the information I'm looking for, namely the dimensions and proportions of the camber in the plank. The last sentence in your post hits the nail on the head.

"Paul Goodwin once posted a description of the spacers he uses to form the crown in his planks, but for the life of me I can't seem to find it now..."

This is exactly the information I'm looking for. All I can find in the CW is advice to the effect of "form the jig to the shape that you want". Unfortunately, I don't quite know what it is that I want. Anyway, I do appreciate the headsup.

DNewbie

[Geoff Sobering]

Sorry I don't have the info. right here.  I've (fortunately) acquired two plank jigs, so I've never had to think about the details of the camber (not 100% true, I modified one jig, but that was five years ago so I've forgotten the details).  I'll try and measure the jigs I have tonight and post the profiles.

[Scott Brown]

I have a drawing that can help you out.   It's a PDF.   If you don't mind posting an email address, I'd be glad to send it to you.


Browner
5298

[DNewbie]

Scott,
That would be great! email is paul.sobon at cit.com. (leaving out the @ to foil the spambots.)