Batten seam in plywood

[maa. melee]

I recently ordered Atkin's Russel R. plans. He listed both lapstrake and batten seam construction although mentions nothing about dimensions for the latter. I don't have the plank stock yet so I cannot say what my plank widths will be, however, would a 2, 2.5" strip of 3/8" or 1/2" plywood notched into the frames work well for battens? I'm not using epoxy so I'am alittle worried about delamination. I figure 5/8" plank on 3/8" battens riveted on burrs will suffice (and make caulking easier).

Another issue is finding my planking stock. Any places in boston area?

[RonW]

http://www.boatdesigns.com/cgi-bin/store/web_store.cgi?page=runaboutplanking.html&&cart_id=1043511_8126

NO....use solid wood, not ply for battens, 3/4 inch thick.Scroll down this site and see a picture of batten construction. Ply would be too flimsy for battens even if it was 3/4 inch ply.

[maa. melee]

3/4" solid wood battens behind 5/8" solid wood planking? That doesnt leave too much frame behind the batten notches.

[RonW]

Sure it does, what are you going to do, have them only a 1 & 1/2 inch wide. They are probably somewhere from 2 to 3 inches wide, and remember that the frames are supporting the planking as well. The battens are just to replace the caulking in a carvel style construction. I am sure atkin spells and shows all.

[Mike Dawson]

An Atkin example: 26' Twilight flat bottom sloop
1.5" x 2.5" oak frames, 11.5" on center
0.5" x 2.25" oak battens notched into frames
0.75" cedar planking on the sides
1.125" oak planking on the bottom

[JimConlin]

An ignorant question-
In batten seam planking, are the battens stopped at the frames or notched through them? If notched through, does this make them stringers?

Another ignorant question-
If the function of the batten behind the seam is to hold two adjacent planks together, why shouldnt't it be plywood and have some cross-grain strength?

[maa. melee]

yes, the battens are almost always notched thru the frames unless theyre exterior battens mounted on the outside of planking. Well i figure the batten needs all the longitudinal support it can get and needs to flex in the same way the planks do. rivited on burrs and smeared with some sort of sealant. Apparently solid wood is the way to go for trad. boatbuilding.

editted to add: in the plans, atkin specifies either clinker or batten seam const. the frames ar 1.75 on deck and 2.25" at the chine (.75" thick thru and thru) so .75" solid battens are the way to go?

[ 02-28-2005, 06:42 AM: Message edited by: maa. melee ]

[boatlover]

maa. melee:

It isn't the RUSSELL R, but I have a copy of part of the article the Atkins wrote for SHARPSHOOTER, a 21'11" vee-bottom, Bahamian sloop, to be built using batten seam planking.

The sloop was framed with 1-1/2" x 2" white oak, planked with 3/4" cedar on 1/2" x 2-1/2" white oak battens, for both bottom and topsides. Atkin called for 5 planks each side of the keel in the bottom, and three planks in the topsides.

Quoting from the article:

"All battens must be let into the edges of the frames and fastened with galvanized wire nails or screws. Battened seamed planking should not be caulked, rather fit the joints close and set in thinned white lead or some other equally long lasting seam compound. The planking will be fastened to the frames with galvanized iron boat nails; and to the battens with copper boat nails riveted over burrs. or bronze screws; ...... "

(My only question/hesitation would be the mix of galvanized iron and copper/bronze fasteners in close proximity.)

HTH

Regards,

Ed R