Strip-plank Chine

strip-plank composite construction has as many construction method variations as it does builders, so I'd like to hear from those with experience as to how best to tackle the detail for a hard chine. (Actually, in this instance, it's more of a 'knuckle', but the essence is the same..)

I've attached a scribble to give the general idea. Planks are 19mm thick and generally 42mm wide. The chine itself varies in width from 0 at the bow to 50mm wide as it moves aft.

My initial thought was to simply run 3 planks (as per blue lines) and then shave off the protruding timber on the inside face after the molds are removed. But this complicates the mold shape somewhat as it would nee to be 'notched' to varying degree to accept the inner-most plank.

Next thought was to run the lower planking up higher ( red or green lines ) which would simplify the mold shape but complicate the planking as a 3rd plank would nee to be shaped in order to fit in between the topside and bottom planking.

Any thoughts, suggestion greatly appreciated....

 

I think, do lower planking first to the point where you spile the uppermost piece against the INNER transition line of the upper planking (the green plank would then be slightly higher than shown).

The upper planking would then lie against the outermost square corner of the lower course. The lowest plank of the upper course could then overlap the uppermost plank of the lower course by a couple of inches, leaving enough to recut afterwards to a fair line. The vee pocket created could be filled with either shaped wood or epoxy and filler. The inside could be filled to allow smooth transition of cloth from lower to upper courses, and to shed water.

 

I've built and designed a few different chine arrangements and stripping is an easy way to get a rolling bevel with reasonable effort. I usually set up the chine pieces to lie fair with the lower futtock and plane the remaining outer edge to match the bevels on the topsides. The same is true of a laminated chine log, though not quite as strong.

 

Thanks guys...
Alan - unfortunately both the angle between topsides and 'bottom' planking, and the chine width vary, so I'm not sure that you system would be suitable. I'd also like to avoid filling large voids or shaping planks to fit as much as possible.

PAR - I think you're suggesting doing things the opposite way to that which I put up in my 1st scribble. (I always think better in pictures than words, so attached is another. Mold is in black, bottom planking in red, topsides in blue and required trimming in green). Are we on the same page?

 

Ooops - forgot the attachment...

 

You won't get out of this without shaping the chine to a rolling bevel. The width of the chine, as you said, is from zero to about two inches wide. No matter what, you will be planing a twist into whatever material stands proud of the actual chine (where the two planes bisect).

 

Yep, the second image has the method I've used. With your (what appears to be) lifting strake, I'd consider this a better candidate for a laminated chine log (horz. laminate). This could be done with the stock following the sweep of the chine (stock is rotated 90 degrees to second image), though then you're back to the problem of beveling to fit lower and upper futtocks. You'd also have to fight edge set as you sprung them to the molds, but that's what pipe clamps and fat friends sitting on them are for. If your strake has a constant angle, then a built up chine may also be in order. It's plan view shape can change, but at least you'd be able to stack the strake side of the chine log on top of a beveled lower piece. It would look a bit like an inverted "L" with the beef of the chine on the lower futtock and the strake a shelf.