strip planking for a squirt

reidstrand · **Joined:** Wed Sep 16, 2009 8:03 am **Posts:** 4

Well, I'm about half done with a stripper canoe. One of the most pleasant and relaxing experiences of my life. Way more fun than actually paddling a canoe.

Which brings me to my question. I've purchased the plans for a squirt, and picked up a 1956 Johnson outboard. I have access to inexpensive woods. Would it be possible to adapt the canoe stripping method as a replacement for the plywood? It would be epoxied and glassed both in and out, and I would be using 1/4' thick strips with bead and cove construction.

Basically:

1) Would the composit sandwich be structurally sound on a planing hull?
2) Would I just skip the battens and strip directly over the frames?
3) Would gluing the strips directly to the frame members be asking for trouble (cross grain issues, even when encapsulated)?
4) Should I consider a stronger wood than cedar? My understanding is that the real strength comes from the "sandwich" of fiberglass and the wood is somewhat unimportant.

I'm pretty new to boatbuilding but I do quite a bit of furniture construction. Any other advice or guidance would be greatly appreciated.

Bruce Dow · **Posted:** Tue May 25, 2010 2:47 pm

Hi Reid.. This is a fun question to think about.

I have not done this, so all of the typical caveats apply. this is my OPINION only....

1) I think So
2) Yes... but see Q5)
3) Probably ... but see Q6)
4) No.... cedar is a great wood to work with for stripping.

I have built both stripper canoes and plywood boats, and the process is very different.

Let me give you two more questions:

5) How do I keep the the hull shape fair? On your canoe, the moulds were probably 1' apart. On a plywood design, they are probably 2' or more apart. I would worry about "flat spots" between the frames. You could probably build some temporary (removable) station moulds to put between the frames to help hold the shape while stripping. (someone with this boat under construction may be able to give you the lofting points mid-way between each of the current frames.. or you could try to eyeball it.)

6) How do I glass the inside? Would I pop the whole monocoque off the frames to glass the inside, then epoxy/screw it back onto the keel and frames? Or would you try to do a patchwork job of glassing the inside among the frames?

Where are you located?
Which stripper model are you building?
Are you REALLY half done? (grin) What stage are you at?
Feel free to share some pictures.... we love 'em.

BulldogBoater · **Posted:** Tue May 25, 2010 7:04 pm

Having build both the Squirt in plywood

And a Strip Planked Fishing boat of my own design:

I have to say that Bruce has some very good points.

1) Keeping the hull fair will be extremely difficult. That fishing boat above looks good in a picture but anyone can see the hull isn't fair in person. That and it always pulled to the right.

2) Fiberglassing the inside is difficult at best and frustrating to no end to get it right.

All that said, I think it could be done but it will definately be much more work.

Good Luck,

KB

reidstrand · **Joined:** Wed Sep 16, 2009 8:03 am **Posts:** 4

Those are some great responses. Thank you.

The canoe I'm doing is the Glen-l Stripper. Oddly enough, the formes for that model are 2 feet apart on a 16' version, even more on the 17'. The books I read all recommended more frames, 1 foot apart. I think that would make it easier, but it is definitely possible to do at 2 feet apart.

My thought on the building process was to add an extra frame towards the front, based on an "eyballed" approximation, and to glue and screw the strips to the frames as I build. Then to fiberglass between the frames, thinking that the look of most of the interior fiberglass would be hidden and therefore somewhat irrelavant. However, the idea of lifting out the frames, fiberglassing, and then installing the frames is very interesting.

OK, prepare for heresy from a novice-- How important is absolute fairness on the sides? Seems to me that with a planing hull, its just the bottom (flat) and maybe a little of the curve at the front that will affect performance. Beyond that, fairness becomes more cosmetic than functional and a flat spot could be treated more as a "redesign opportunity" than a defect????

I really think at this point my concern is strucural. Would the hull be able to handle the pounding the same way a fiberglass hull would?

Bruce- to answer your other questions, I'm in Minnesota, and no, I'm probably not half done, but if you're familiar at all with the theory of Zeno's arrow, I'm starting to believe I'll never be truly done, just water ready. After taking the winter off since I'm working in the garage, I'll be fiberglassing the inside on Friday. I've got all the trim pieces and seats pretty much ready to go, so then its pretty much varnish and installation time. However, I keep thinking of things to add, such as beverage holders, built in tackle storage, dry storage in the front end, maybe a cooler.....

Pictures will be posted soon, but I guess I'll put them in the proper category. Thanks.

graham mackay · **Posted:** Wed May 26, 2010 10:11 am

Hi Reid,
My plan for my Hercules is to strip plank exactly as you describe but over my side plywood. This way I retain the correct hull shape but get the beautiful strip-cedar effect.
Good luck,
Graham

Fred Østli · **Posted:** Thu Aug 09, 2012 1:14 am

Hey

I see this is an older post, but I was about to post a similar topic, so I am hoping for respons on this thread.

What is the result of this buid?

I am thinking about strip-plank with epoxy sheeting both sides building a Squirt. I have just purchased plans, waiting for them in the mail. I have been thinking about the challenges this will bring, but I think it can be done. my greates consern is: Will the hull will be equaly strong as plywood using strip-epoxy laminate? The reason I am thinking about this method is that I acess to free strip-plank materials, and I like the idea of using wood from my own forest in the build. (Scandinavian spruce in a classic american runabout

)

I am also considering wider strips than common in kayak-builds because it will speed up the building. Since this is a plywood design it should be posible using wider strips.!?

I have been reading a lot about strip plank epoxy laminate, and many says its pretty strong if you glass both sides. I have also startet to make a test template piece to test the strength.

Regards

Fred

Iggy · **Posted:** Thu Aug 09, 2012 9:22 am

Fred,

For the same of shape, simplicity & strength I would suggest building the squirt hull using 1/4" plywood and then strip planking it overtop for looks.

You could foregoe needing to fiberglass the interior if you use plywood on the inside, and it would ensure you will get the proper shape to the hull.

Squirt does not take a lot of plywood for the hull, and because its not going to be seen you can probably find a pretty good deal on a suitable piece (something with no interior voids, waterproof glue and rot resistant) of plywood, like luan.

Fred Østli · **Posted:** Thu Aug 09, 2012 3:14 pm

Thanks Iggy.

I know the cost of ply is small on this boat, but I really was curious about if its posible using only strips,. I might build a zip or similar if this suceed. My main issue is to be shure it is strong enough in this design. I believe the shaping can be done with some temporary frames. I will not eyeball this temporary frames, they can be measured by temporarly fasten a playwood plank over the frames. Maybe making cardboard template.

I will do some testing also before I deside, by making some templates and compare strength with plywood

Regards

Fred

Fred Østli · **Posted:** Tue Aug 14, 2012 12:40 am

Hello again.

Thinking more about what you suggest Iggy, and it might be a good idea. Another reason for me to use strip-plank is poor acess to marine plywood in this part of my country. I must choose driving 800 kilometers or pay a lot for transport if I want to use marine plywood. It might be possible to use non-marine plywood if I laminate strips on top of it using epoxy both sides! Do you agree? I also think it might work to use 1/8' or 1/6' plywood if the strips also is 1/8'. This will be a kind of cold molding...

Happy for any respons! Still waiting for plans, they have to travel around the globe, giving me good time to consider solutions.

Regards

Fred

Iggy · **Posted:** Tue Aug 14, 2012 8:19 am

Its a bit of a hard call for me on suggesting non-marine plywood. The reason I like marine grade plywood has more to do with eliminating internal flaws (voids) in the plywood so that it does not crack when bent around a hull. Having waterproof glue in the plywood laminations is also critical, and you probably still want a fairly rot resistant wood as well.

The 1/8" plywood I've seen is actually almost too flexible, so it might not make a great base to laminate on if it keeps flexing out of shape. You might be able to find stiffer plywood at 3/16" instead.

galamb · **Posted:** Tue Aug 14, 2012 10:39 am

If you are willing to go the expense (I think about 35 bucks), the "Gougeon Brothers on Boat Construction" (whatever the latest version is now - I have version 5) dedicates a whole chapter to strip building (both strip plank and strip composite), including all their testing to show how to build with strip comparable to different marine plywood thicknesses and how to jig it up etc to help keep things true.

(it also includes chapters on hard chine, mold/plug, stringer frame and compounded plywood)

As an added bonus you get the "bible" on epoxy from the founders of West System plus all the technical data you could ever want.

Fred Østli · **Posted:** Tue Aug 14, 2012 1:47 pm

Thankyou Graham, I will look for that book you recomend. Trust me, I am not a proffesional!

And look what I found!: http://www.westsystem.com/ss/assets/How ... 061205.pdf

Regards

Fred

Fred Østli · **Posted:** Wed Aug 15, 2012 2:27 pm

Hello again. I have been reading a little in the Gougeon Brothers book. In chapter 23 they compare strip-plank and plywood with epoxy. An example: 1/4' cedar strip with two layers 6 oz glassing weight near the same as 1/4' plywood with 1 layer glassing. When you compare strenght its about the same, and compare stiffness the cedar strip with epoxy is stiffer (less inches of deflection) It seems like weiht strenght and stiffness is close with this alternatives. I made a board with 1/4' spruce-strips and compared it with 1/4' plywood and they felt like the same stiffnes.

Although I might use plywood after all, but I have not desided yet

Regards Fred

Iggy · **Posted:** Wed Aug 15, 2012 3:05 pm

We have a strip planked cedar canoe in the family that is over 30 years old and just as strong as it's ever been.

My challenges with strip planking isn't so much the strength, but more the shape and the challenge of trying to fiberglass the interior of a hull.

However, I can't think of any technical reason why you couldn't strip plank a squirt. It would certainly be unique and I bet the hull will be more than strong enough.

I am betting plywood is faster and simpler, but I wouldn't say superior.

Fred Østli · **Posted:** Thu Aug 16, 2012 12:15 am

Thanks for your replies Iggy, I will take your advices into my considerations. I am thinking about a solution to ovecome the challenge with shape and also fiberglassing the inside, but I need to do some testing. I do like this type of challenges, and i have a bad habit not to choose the simplest and fastest solutions! :wink:

Fred

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strip planking for a squirt

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