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Permalink Reply by chris towles on April 28, 2011 at 1:45am

are you asking about length or thickness? if your boat is 17' bow to stern the ouwale is likely 18' or so. if the boat is a 17x52 or 17.5x54 kit boat or built from plans the outwale is is generally 17' or 17.5' which is about 15' 6' or or 16' bow to stern. the chine battens are obviously shorter but they are the length of the bottom of the panel. on my 16x48 i think the battens were just over 14' but that may depend on your stem angle and rocker profile. alot of variable there.

 

as to thickness, 5/8 seems right on the money. bends well and is thick enough to be strong. that goes for both the battens and rails. you could go as big as 3/4" but it will be harder to bend. you could also go 1/2" which will help with bending but will be less strength. height is usually 1.5". 

 

on the battens, you want as big a roundover on the top  outside edge. this helps prevent "chine dip" in squirly or big water. 3/8" works good, but if you have a 1/2" roundover thats even better. the bottom outside edge (the chine corner) should be left sharp, just like the edge on a ski. you'll likely want to cut a small angled bevel (10-12 degrees) from the inside bottom edge twords  the outside edge, because once you bend the batten, the outside bottom edge will stick out way proud at an angle, and thats not what you want. that said you do want to install the batten and make your angled cuts so that it is slightly proud so that it protects the actual chine joint on the boat

 

for the gunnel stock, i would do rails of 5/8, but i would cut a 1/4" rabbet into  whichever rail runs next to the ply. this will make a 7/8" batten (5/8 rail plus 1/4 lip). the lip covers the end grain of the ply and protects it from taking in water. 1/4" or 3/8" roundover on all this stuff makes for some really nice looking stock when you are done.

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Permalink Reply by Russ Tuter on April 28, 2011 at 7:58am

I did my chine caps and outwhal out of 1/4" X 1 1/2" CVG Red Fir.  I bedded them in Sikaflex and nailed on with Bronze Ringshanks.  I am now laminating a 1/2" X 1 1/2" piece of CVG Fir over them with sealant and SS screws.  When my outer chine cap gets chewed up, it will be easier to replace.  Besides, I think it looks better.

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Permalink Reply by Don Hanson on April 28, 2011 at 8:17am

 

  Another tip

  You may want to hollow,  very slightly, the backside of any cap rail or rub strake that will be mounted against a flat surface, to make it 'land' properly and to leave some space for bedding compound or caulk.  This is common practice for parts that may need to be removed or replaced periodically.

  I am currently replacing the 'rock-shoe' on a Don Hill boat.  In place of the UHMW chine guard, I am using a second layer, a replaceable white oak chine cap guard, mounted with SS screws.  I will will go very slightly concave, except for the ends, on the backside of this piece. 

  I use small round shoe hand-plane or a scraper with a radius end.

  Another trick..If you would like to add strength to a piece without sticking a bunch of ugly goo over the top of it...(Francis Herreshoff called fiberglass "Frozen Snot")  I have run tows of carbon fiber behind the piece in a groove routed into the wood.  On a convex member, this greatly increases fracture resistance and tensile strength, and no one sees it.  You can reduce the scantlings of your boat using this technique. 

  Don Hanson

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Permalink Reply by Mike Baker on April 28, 2011 at 5:18pm

Hey Jordan,

 I like to use 11/16 thickness on the inner and outer gunnnells. I also like them to be 1-3/4" wide(1/2 of a 1x4 if you are using dimensional lumber). As for the outside chine batten I go no thicker than 1/2" I actually prefer 3/8". My first boat (which I still use) has chine battens that are 3/4" thick and the chine dip is horrible on that boat.

I have done the roundover on the chine batten like Chris suggests but I prefer to cut a 30 deg. angle with a  table saw.

Mike

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