how thin is too thin, and how wide is too wide?

[kafka]

As if the title doesn't say it all

I was looking into building a strip plank canoe, and was wondering just how thin and how wide the planks could be. Since the whole thing will be covered in a layer or two of fiberglass, I was thinking it could be pretty damned thin, but I've never made one of these, so I could be crazy.

Any suggestions?

 

[Dan Lindberg]

Thin?

Well most fiberglass canoes don't have any wood so I'm not sure what '"too thin" could be. If you had a mold or existing canoe you could layup the glass over it (with the appropreate protections to not harm or stick to the existing canoe) without any wood.

With that said, the "standard" is 1/4 inch, with many strippers made that are 3/16 to reduce weight.

There is a well known builder who uses 1/8 inch as his "standard" layup. Note that generally with reduced wood thickness more glass is added, which can result in a stronger boat.

On my current project, the bottom strips are 3/16 with the sides 1/8, with 2 layers of 2.85 oz satin plus 2 layers 2.3 oz satin in the football each side.

Forgot, width, the standard is 3/4, but many canoes have been made with both narrower and wider strips. You might want to stick to the 3/4 in the areas where the hull curves, wider, I've seen up to 1 1/2", on the flatter areas.
Dan

 

[jackbat]

Don't make life hard!

Kafka,
You said everything you needed to say when you said you have never made one of these before.

As a boat designer and one who has taught hundreds of people how to build strippers I feel very confident in saying you will only be making your life difficult for no reason if you don't use the standard 1/4" strips. If for no other reason than you will need to buy Bead and cove (flute) bits in order to shape the edges and they come in a standard 1/8" radius. Stripping is not limited to 1/4" strips. In fact you can build larger boats with 3/8" and 1/2" strips and those bits are realatively easy to find as well. Typically strips of that size are base layers for cold molded hulls.

The biggest favor you can do yourself as a first timer is to make sure that your strips are uniform and all the beads and coves are centered well. This will ensure that your strips will meet perfectly and the amount of fairing of the hull will be greatly reduced. If you do it right, your hull will be something less than 1/4" because you will have shaped and sanded the hull a bit, and the thickness will vary slightly over the hull. Cedar is not a heavy wood so don't worry about saving 2 to 3 lbs by thining out the strips.

As for the width of the strip, it will depend on the hull shape. My Rob Roy is a very straight forward design with very little curve or swing in the fore and aft section so using 5/4" strips is an option. However the Prospector or Companion boat have compound curves leading into the stem and you will need to use 3/4" strips for those boats. So, where largers strips work sometimes, 3/4" strips work all the time. Get the hint.

Presumably you will be using at least 6 oz of cloth on both the inside and the outside. That combined with the epoxy will give you the strength that you need. If you will be banging off of rocks and dragging it up on shore, you should put another layer on the outside of the bottom of the boat.

Good luck, the first boat is the one you will always remember.

Jack
WWW.sandypointboatworks.com

 

[Dan Lindberg]

Two more comments,

Don't get too worked up about B+C, literally 1,000's of boats have been built with square cut and hand beveled edges and they look fine. It doesn't take much to bevel the edges and get a tight joint. With that said, the B+C does make laying up the strips "even" easier and may be more forgiving. If you buy a kit, you might want to make sure you get the B+C, but if you are ripping them yourself, it's not necessary. Only you can decide whether the extra machining operation is worth doing or not. If you don't, use small spring clamps to hold the strips in alignment between the stations.
"need to buy Bead and cove (flute) bits in order to shape the edges



Agreed, whether width or thickness, having all the strips the same "solves" a lot of problems.
"The biggest favor you can do yourself as a first timer is to make sure that your strips are uniform."

Dan