what grade?

Hello all. I am researching the wood I need to build my 28foot cat boat. I think I have the plywood figured, But I am not sure on the cedar that I will be stripping for my hull. I believe I want a "clear" grade, but should it be ; a,b,c,or d clear? obviously the better the grade, the better the wood, and the higher the cost. Cost is an object, but I don't want my boat to "break".

Thank you

Bob Mc

 

Welcome Bigmccc. http://www.wclib.org/R17-PDF-Online/WCLIB/gradebook3.htm

http://www.wclib.org/R17-PDF-Online/WCLIB/pdfs/NGR-interps-2008.pdf

 

Thanks..this gives me great info to read (and I will) about grades. But I still need to know how good a grade I need to strip plank a sailboat in ceder (before covering with fiberglass/epoxy.

 

Fiberglass and epoxy will hide a lot of sins. Small closed solid knots should cause you no problems as long as they aren't too close together.

This is where I go for cedar and hardwoods.: http://www.intercitylumber.com/

They also have milling capability.

 

Hoyt, the above address is bad--cannot be found.

 

Sorry about the typo.

It will work now.

http://www.intercitylumber.com/

 

Strip planking is pretty forgiving in most formats, but that's the crux, which type of strip planking are you using. For example, some forms of strip planking are really little more than wooden cored composite structures, while other have no sheathing and rely solely on the strip bonds and/or fasteners and longitudinal stiffness of the married pieces. Originally, strip planking used only fasteners, no goo, no fabrics, no veneers, etc.

As a result it's important to identify the type of strip planking it is, so you can determine the role the strips play, which will require a specific quality. Composites can use really crappy strips and still work. Traditional strip plank will need quite good stock and of course there's a bunch in between.

Which design are you building?

 

I will be starting this summer on a Mike Waller 880 28' cruising catamaran.

 

One of the nice things about strip planking is that you don't need super long pieces of clear strips. If you are stripping from a board with knots, the knots will usually break the strip right there, and you just have two shorter strips. So long as the strips span 3 frames, and you are coving the strips, it shouldn't make too much difference. You are ending each strip on a frame mold anyway right? So that means you are already probably generating a lot of waste wood from perfectly clear pieces, so I don't see this as causing more waste wood.

 

I dislike ending strips on station molds, preferring to end them between molds. I back them up with a temporary block until the goo cures. It produces fairer strip runs this way. This particular design is a composite strip plank build, though not especially light, not bad and well thought out for a cruiser. Strip selection should be based on species density and it looks to be in the 25 - 27 pound cu. ft. range, which explains the cedar requirement. Foam composite bulkheads would help lighten her up a bit, if desired. You'd get more capacity and slightly better performance this way.

In Florida there's a number of place to get WRC, though white pine may be an alternate choice. I'd buy it as dimensional stock (2x's) and rip them down on a table saw. You'll have some waste (the blade kerf will make you cry alone), but it doesn't need to be select, AA clear stock, you'll just cut around the knots as you apply the strips, as Scot has mentioned. No need to scarf the strips, just butt them together on the molds, the sheathing is structural and will fix all ills and unfairness that will occur. I do like to cut a 45 degree end on strips, with this bevel facing the hull. It helps to pull the wayward ends into alignment, as they're tacked down to the molds or temporary blocking.

I have a good source about 15 minutes from me in Deland, Heritage Forest Products. They sell kiln dried WRC in dimensional sizes. There's several places in the Miami, Tampa and Jacksonville areas too.

 

Remember to give the cedar shavings and sawdust to your wife. She can make potpourri with them.

Scrap cut offs can be made into cedar coat-hangers. Just add a bit of wire for the hook.

 

+1 for ending between molds.

I may have to try the 45 degree cuts on the ends.
I just looked at my recent kayak, and the butt joints are occasionally quite obvious, probably from not trimming back the ends enough.

 

Couple of good points:

1) If I save some money (maybe a lot) by buying cedar with small tight knots, while ripping when I come along a knot that would be a good place to make two shorter pieces *(a natural break so to speak)

2) Where to scarf the joints. I was assuming the ends needed to be joined at a mold, but from the comments..perhaps not.

3) for months I have searched for suppliers of wood. from this post I have looked at several. Sometime in the next few weeks I am heading over to Tampa to look at intercity lumber.

 

I buy my cedar at Home Depot and Lowes.
It's difficult to find "relatively" clear lumber there and it is wet (not kiln dried).

Generally a trip will result in 1 or 2 boards a visit, and I have to sift thru most of the stack on display (be sure to put the boards back neatly - so they don't stop us sorting). So you need to be dedicated to get enough wood. But the ricks of wood get changed out between every day and 3-4 days (where I shop).

I generally want 2" or 4" boards since there is a little less wastage compared to 1" stuff.

If you cut the wet lumber into strips, it will dry very quickly. A couple of weeks?
I cut it a little oversized, allow it to dry, then cut every piece to my chosen exact size - so that I get consistent strips. Consistent strips just makes it a little easier to strip the boat more evenly and decreases the amount of fairing - especially on the inside.

I've seen the suggestion that places that sell decking lumber might be good sources. You need to check that they will let you sort for the best stuff. Many places won't.

If you are cutting out knots, don't cut too close. The wild grain around a knot is easy to break and hard to fair. If you are going clear, it also shows up as a very dark area of wood when the epoxy hits it. Which you might not mind.

Welcome to the snipe hunt!

4 cents worth.

 

hey upchurchmr,,,do you run your boards thru a planner? before you rip them? after you rip?