On Battens

Caveat: this my own personal, emperical knowledge and experience!

Wood for Battens: Eastern White Pine, True Mahogony, Alaska Yellow Cedar, Port Orford Cedar, Douglas Fir ( old growth if possible) , are to be preferred. Rarely hardwoods for battens of length. Ash is fine for short ones say 6 to 8 feet. Shorter lengths of most any wood can be used for say diagonals or places where there is no curve.

Lengths:
Sheer= 1/2 x 2 inch and longer by several feet over both perpendiculars.

Waterlines= 1/2 x 1 1/4 inches with a TAPER on both ends. Taper allows the batten to tuck up a bit at the forward and aft sweeps.

Body Plan= 1/2 x 1/2 inch with if possible a thinner center to flex around the lines.

Long lengths are spliced with about a 1 in 12 splice. The glued up splice is made proud and planed or scraped down to final dimension.
No rivets or nails through the splice. You want it to be as flexible and fair as the rest of the batten. Weldwood Plastic Resin glue was favoured but later on we did use the yellow stuff even though there were rumours that it creeps under load. Cannot recall ever seeing that myself.
Nails are driven along side the batten NEVER through the batten. Initially blocks of steel, edges smoothed off with felt or neoprene glued to the bottom would be used to nudge the batten into fair. After lots of squinting and bending over and looking at the line, it would be nailed( alongside!)to the loft floor. Sometimes a pail of awls would be used to set the batten in place but usually it was the nails alongside the batten. Blue Plaster nails were mostly used for this work. Thinner shank and being dark blue or black did not cast another distraction to the eye. Lines were drawn with drafting pencils and artists colour pencils NEVER pens or marking pens.
Reason? Those inks would bleed through the paint when the floor was prepped for the next job. Oil based paint in palest grey or white tinted with black was used. Natural light or flourescent light was preferred over incandescent. Incandescent casts shadows don'cha know.

As mentioned before, I have used battens 1 x 3 inch x 40 FEET long out in the field. Took most all the layout crew to 'conga line' that batten out to the hull. Approximate measurements were taken, soapstone marks were made on the steel plate, clips were tacked on, batten set in clips, wood wedges used between batten and clip to raise batten to line marked. Leadman would stand back, waaay back, look at the line and with hand signals indicate which wedges needed to be snugged up or slacked off to bring batten into a fair line. After much squinting and after everyone had a chance to look at the line and add their approval, a soapstone line was drawn on the plate.
The batten removed and 'conga lined' back to the loft and the layout people assigned to that section would then punch dimples in the plate along the line at about 3 or 4 foot intervals. Then the section became the domain of the ship fitters and burners under the watchful eye of the layout person.

Right handed people it may best to look at long lines on the loft floor through your legs backwards...Picture the cartoon with the fellow kissing his arse goodbye, eh.
Most Left handed people don't need to look at the line this way. Something about Right brain vs Left brain. Believe me it does make a difference
When in 'white hat' mode, I would use my left handed people for layout and special fitting jobs. Righty's, unless old pharts like me, initially didn't have the training or experience to over come that brain thing.

 

Dave, a boat shop that I visit infrequently has made up some fibreglass battens that they swear by. They laid up a bunch of uni-directional glass on an arborite counter to a thickness of about 5/8", and trimmed the "wild edges" when cured. This gave them a tough, springy batten of a consistant stiffness and accurate edge (providing that they use only the "shiny" side to define the line). I've not used it, but from what few visits I had to their loft floor, it seems to produce a fair line. Any comments?

 

New one on me Mike but, what the hell isn't everything these days?

I imagine if they do lay fair, the potential is for some fine battens made by a good feeberglaz shop.

But with all the computer stuff I don't see it being a lucrative sideline. Last yard I worked at, Campbell's here in San Diego, was not the cutting edge of west coast yards.
But it did keep a few old remnants like myself in harness for a bit.

 

I do 'most all my stuff on the 'pooter, but would be the last to say it can replace the old tools - makes some stuff faster, mebbee, but a fair batten and a good eye still beats a digitally-derived line hands down. Latest project I did was a 60-foot sailing yacht; all the frames were laid out & laminated to computer generated lines. After set-up & bracing the marks for the sheer that had been marked on each frame from the digital data were faired by eye & batten and discrepancies found. Not much, mind you, and it is unknown whether the errors were computer generated or from "relaxing" of the laminated frames or creeping errors in the frame set-up, but the eye-sweet batten found variances in the fair line of the sheer of up to 3/16".

The 'pooter is a wonderful tool, but not yet the only one in the shop.

 

You can get fiberglass battens from a sail supply. They are superior to wood in consistency and flexibility. For short battens, you can also use plexiglass. It comes in up to 8' sheets. Wood is handy because it can be cut and planed in the shop. However, it is more likely to break and warp with humidity. I confess to still use wooden ones at times.