Question for the gurus

[Wild Dingo]

Okay now Ive pretty much decided to go strip plank rather than ply and am still considering a traditional build but Ive been wondering... dangerous activity for yours truely but none the less the question must be asked

Now for hypothetical debates sake...

I have the plans for Grey Seal... can she be build strip plank? if so how does one change the sizes of the of the ply planks to strips? how does one calculate the difference in weight from ply to solid timber strips? Indeed is it necessary to do so rather can on simply use say Western Red Cedar strips of the same thickness as the ply? {ie for 1/2in ply exchange for 1/2in strips

Curiostity is a very hard task master be patient with your fellow shipmate! ;)

[Wild Dingo]

On another note Ive also got the plans to Fame can she be built strip plank?... on reflection of course she can and also upside down but how then does one calculate the strip thickness weight differencial? Michael??? Other designers? ooh knowledgeable ones!

[ 02-28-2005, 10:52 AM: Message edited by: Wild Dingo ]

[StevenBauer]

Shane, The Macnaughton Group have published a scantlings (timber size) table that you can use to size your strips. I thought it was online here:

http://www.macnaughtongroup.com/default.htm

But now I don't see it. But not to worry! A quick online index search revealed:

/Scantling rules:/for cold-molded construction/Thomas MacNaughton, 4:17

So just check out page 17 of WoodenBoat # 4 and Bob's your uncle!

Steven

[Wild Dingo]

WB number 4? WOW!! all the way back when eh?! No worries thanks Steven :cool:

[StevenBauer]

I guess it was 'The Woodenboat' back then. smile.gif I just finished reading #14. I started with #1 after the holidays. Great reading. I'm really wondering about all the boats highlighted in these old issues. Are they still around? Who owns them? How have they held up? The article about how much it costs to build is a hoot! The article complained about the cost of labor and materials but if you could get those rates and prices now you'd be dancing a jig. :D
They even had a Forum in the first few issues! It didn't take off and was dropped but they tried way back in 1975.

Steven

[mmd]

Changing from carvel to epoxy-strip planking for Fame is not a big deal. One of the major things to pay attention to is the difference in weights if you use wood species different that the original plans call for. On a boat the size of Fame, changing from mahogany on oak to, say, Douglas fir on laminated Douglas fir, the weight difference would be possibly over a thousand pounds. This can be good, if you plan for it.

Going from lapstrake ply to strip cold-moulded is another matter. Ply is stiffer than same-dimension whole stock, and the overlap of the strakes effectively creates a series of strenthening longitudinals, making the whole structure very strong for its weight. To get the same strength in edge-glued strip construction, you would have to increase the scantlings to compensate. This would add weight to the hull, which may have adverse effects. Plan carefully to avoid disappointment.

[George Roberts]

Wild Dingo ---

As I recall Red Cedar is about 2/3 the density of plywood. So 1/2" plywood is about the same weight as 3/4" solid wood.

If you are considering glass over wood:

McNaughton core thickness is a scant 5/8". Gerr's core thickness is a plump 1/2". Close enough for planning.

[Wild Dingo]

Originally posted by mmd:
Changing from carvel to epoxy-strip planking for Fame is not a big deal. One of the major things to pay attention to is the difference in weights if you use wood species different that the original plans call for. On a boat the size of Fame, changing from mahogany on oak to, say, Douglas fir on laminated Douglas fir, the weight difference would be possibly over a thousand pounds. This can be good, if you plan for it.

Plan carefully to avoid disappointment.Oh I intend to Michael I intend to!!... interesting that you say this can be a good thing.. really your going to a lighter hull by substituting the mahogany to the fir arent you?

We shall have to have a discussion on this I feel you and I :cool:

George thank you mate! It is just such info I was looking for :cool:

[ 02-28-2005, 11:55 AM: Message edited by: Wild Dingo ]

[paladin]

Now.....back to a remark I think I made elsewhere.....it is easy enough to replace plywood lapstrake with solid wood...just use edge glued strips.....and build the plank of "ply" a little at a time......if you use huon pine you can emulate fir plywood by going from 1/2 inch ply to 3/4 inch strips....or use 5/8 inch strips and cut the pine to slightly less than 1/8 th inch by 3 inch wide to veneer over....easy to build......