Stringer size question

[Bzonic]

I’m a bit reluctant to ask this question because I must be missing something obvious.  So for the Curlew stringers that are 5/8” x 1” and 5/8” x 1.5” what size wood are people buying to cut these from?  Obviously the length is dictated by the kayak length but I’m a bit stumped on the 5/8”.  I have not been out shopping for the red cedar I plan to use but I’m assuming that planks of 1x8,10,12 are what I will find?  With the 1” thickness really being .75”  how are people getting the needed 5/8” that the plans call for?  I was hoping I would only have to cut the one side down and not have to rip a sliver off the entire stringer length.  Thanks guys!

[Hirilonde]

I bought nominal 5/4" x 6"  (1" x 5 1/2") and ripped it to 5/8".  I bought nominal 2"x 6"  (1 1/2" x 5 1/2") and ripped it to 5/8".  But then I have use for the extra material.  You have to buy what you can get and maybe rip it in both directions.

[Bzonic]

Thanks for the info.  Depending on what nonimal size material I find the ripping looks to be the route I need to go.  Although I am curious if I could just adjust my frames to accept the .75 stringers if I find some 1 x material.  That extra 1/8" of stringer material would add weight obviously but I'm wondering if there are any other adverse effects of doing this.  Thanks

[Deltabravo]

The place I bought wood for stringers was able to plane it to 5/8 for me, made life easy.

[Richard Peter]

I don't think it matters if it is 5/8" or 3/4" except for the extra weight. Jeff's plans for the FreeB 12 mentions either size can be used so unless you want to keep the boat to it's absolute minimum weight use the 3/4".

[msaxton]

I just used 3/4" on my nimrod, she will be a little heavier for that and other reasons such as the hatches and foot rests, but im ok with that, as I figured better to have it exactly as I wanted it.

[Bzonic]

Thanks guys.  I like knowing that there is the possibility to have the source of the wood plane it down.  Had not thought of that.  Also nice to know going the 3/4" route is doable.  Maybe the 3/4" weight penalty is worth it for the added durability, strength, and rigidity.

[Hirilonde]

  Maybe the 3/4" weight penalty is worth it for the added durability, strength, and rigidity.

I doubt it.  Larger stringers do nothing for durability, the weak link there is the skin.  The added strength to the frame doesn't help much, the most likely damage is puncture.  Rigidity just makes breaking it easier.  Flexibility absorbs and dissipates forces, in effect making it stronger.  And depending on the wood you use, and the design, it may be that thethicker stringers won't handle the bend around the frames.  This would be most likely with the FreeB 12 which has a lot of bend for the 12 feet of length.

 

It might be just fine to use 3/4" thick stringers, but I would not consider it better in any sense.  Designers give parameters for a reason and bigger is often not better.

[Richard Peter]

While Dave is right about the issue of too much rigidity being a bad thing I realy can't see the extra 1/8" making a whole lot of difference to the rigidity and therefore not an issue as far as a Curlew build. As I mentioned before Jeff's plans for the FreeB 12 say either size is fine so the issue of stringer flexibility is not too critical here as the curlew has loser curves (depending on the wood used of course). In my Mess About 12' build I was abe to bend spruce quite easily for the stringers, gunwales, and keelson. I think what is realy the important thing is that the boat be lashed together well and skinned tightly.

Having said that, if you can find a souce for the 5/8" material you wouldn't have to mess with changing the plans at all which is always a bonus!

Enjoy your build!