Thread: GIS Build in New Jersey, USA
21st Apr 2011, 03:45 AM #1
GIS Build in New Jersey, USA
Itís my turn to begin building a Goat Island Skiff!
Iíve started by making my own sail which is detailed in another thread (which is not yet complete as I write this). But warm weather is coming, so I better get started with the boat part of the sailboat. I recently ordered and received a bunch of System Three Epoxy (from Duckworks Boat Builders Supply). So itís time for me to get some wood and start the butchery!
I will tackle making the mast and spars first. My motive is to have the spars done ass soon as possible, check how much they flex, and finish the sailís head and foot to match. The plans call for Oregon and thatís readily available in the US northeast, although Iím not sure yet how easy it will be to find tight clear stock in the lengths required.
I plan to rip the mast staves from 2x4 stock, getting the wide staves from one board and the narrow staves from another. The remnant from the narrow stave board should also provide material for other parts, inwale spacers maybe? Itís not the WRC specíd for the spacers, and the widest dimension is less than 45mm, but Iíve seen enough variation from other members to feel comfortable doing that. Below is a layout of the cuts I plan to make.
(MIK: Iíve omitted the dimensions from my drawings to protect your proprietary information. If you think this still reveals too much I will pull them immediately)
My first question of the thread: should I try to squeeze the spars out of a 2x4 board? The 1 ĹĒ finished dimension is less than the diameter of the spars by about 2-3mm. Is that enough of a difference to affect the flex of the spars? Didnít someone recently report having shaped his spars a tad thin with bad effect?
Iím inclined rip two halves of a spar and laminate them with alternating grain to fight warping (does that work?). With that in mind, I could/should cut the long edge of the half-spar(s) from the long side of the board and keep the planís dimensions to the millimeter.
Callsign222 recently posted a caution about ripping boards and getting weird twist. Is there any precaution to avoid that? Is it a matter of grain orientation? Or is a former tree gonna do what itís gonna do?
All thoughts are welcome.
21st Apr 2011, 02:05 PM #2
Ok about drawings with the dimensions cleaned off - thanks for asking!
2 or 3 mm is quite critical in the scheme of things. Reducing the diameter of the yard by 10% reduces the stiffness by 35%.
The general trend is to squeeze the diameter up slightly if anything.
21st Apr 2011, 02:25 PM #3
HOORAY! About TIME!
I shall now heckle you incessantly from the Peanut Gallery.
22nd Apr 2011, 05:47 AM #4Golden Member
The "Cosmos Mariner,"My Goat Island Skiff
- Join Date
- Sep 2007
- Savannah GA USA
Starting the Simmons Sea Skiff 18
22nd Apr 2011, 02:46 PM #5
Often the stresses are moisture related. But trees are clever. Timber is stronger in tension than compression - so trees grow in a prestressed way with tension on the outside and compression on the inside of the trunk.
What this means is that as a tree takes bending load the stress has to go up quite high before the compression starts building on the outside of the tree.. So the tree is avoiding the compression stresses on the outside of the trunk where it might fail.
That is the same reason, possibly, that when you split a carrot partway up the middle the two halves tend to spread away from each other.
Carrots don't like to get broken either and have a "heartwood" and "sapwood" layer as well. Maybe - it is important not to push an example too far!
23rd Apr 2011, 12:17 AM #6
I'll check with my local lumber suppliers on the availability of Daucus Carota. I doubt they'll have the required lengths though.
I saw a really nice DF board on the Home Depot shelf yesterday, but was not in a position to grab it. If it's still there today, I'm gonna take it home and discuss with it it's true nature. If it really wants to be a mast, I will be happy to oblige.
23rd Apr 2011, 01:27 AM #7
Widely available... and apparently perfect for a birdsmouth mast:
Daucus carota (common names include wild carrot, (UK) bird's nest, bishop's lace, and (US) Queen Anne's lace) (from Wikipedia)
Just trying to help...
23rd Apr 2011, 10:13 AM #8
23rd Apr 2011, 01:43 PM #9
25th Apr 2011, 11:04 AM #10
Wood curls fly...
Well, I’ve dipped my toe in the water; I made my first cuts and did some gluing too.
As noted above, I brought home a decent piece of Oregon—a 2 x 8 x 14’ board. First lesson: bring the metric tape measure with me instead of doing mm -> ft conversion in my head. For some reason I thought I only needed 9 ft of wood, not 11.6 ft. So I bought a board that had about 9+ ft of clear straight grain for about half its width. Once home, I realized what I did and figured out how to get additional good wood from the rest of the board by scarffing bits together. Several rips and cross cuts later, I ended up with two 9’ halves of a boom, and two extension pieces too.
What’s left over will be used for the tiller and for other projects around the house (utility shelves, etc.):
So, it became time to learn to scarf. I figured I’ll have to do some scarfs during this build anyway, so better start getting used to it early. I went about 20:1. I did a rough cut with the table saw, then used a coarse grit belt sander, then broke out the plane. I haven’t drawn a plane over wood in about 40 years, and I was a young boy when I did. So that was an interesting re-learning experience.
I was not perfect, but I believe the rounding of the spar will eliminate the worst of the errors. The next photo is oriented with the mating surface of this half of the spar facing upward. The side resting on the table will become the outer diameter of the boom.
Proof that I did indeed plane. It’s a pretty satisfying feeling when the technique is done right.
Time for glue. I got my epoxy supplies from Duckworks Boat Builders Supply (the agent that sold me the GIS plans and the source of my sail’s Dacron). They sell System Three products and I decided to go top shelf with the epoxy. System Three’s Gel Magic is specifically designed for joining, laminating, and other adhesive applications. It comes in bulk bottles of course (which I did purchase), but it also comes in tubes that accept a mixing applicator tip. Although it’s more expensive per ounce, it also helps cut down on waste. But then the mixing tip costs money too, so it’s hard to say if there are any efficiency gains or is it just a matter of convenience. For the small amount of epoxy needed to join these two scarves, it was a good way to go.
I did dry runs of the clamping before squeezing out the goo, which is what is shown here. I didn’t bother taking a shot after applying the epoxy, since it looked pretty much the same.
It was raining on and off today and we’re just coming off a rainy weekend, so I don’t expect these joins to be cured overnight. But sometime during the week I will join these two halves together (the scarfs will go to opposite ends) and create a square section hunk o’ wood destined to become a GIS boom. Or I might hold off until I have other gluing to do and then hand mix the batches needed.
So I can now officially say, “I’m building a boat!”
25th Apr 2011, 11:51 AM #11
Welcome to the party!
Cutting and gluing are fun but figuring out solutions is very satisfying. And using a plane - isn't that a treat? I had never used a real plane before building my boat. It took a little bit of practice but it was one of life's "Aha moments" for me when I got it right.
As an aside, I had a "Handy Andy" tool kit as a little boy. I remember using the saw and hammer but being mystified by the plane. Thinking back on it, that plane was a crude lump of steel but it could have been a fine woodworking tool - I was still mystified. I managed to make it through 7th grade woodshop without so much as touching a plane. However, learning to use the hand plane is one of (if not the) most satisfying skills I gained while building my boat.
Looking forward to more of your project.
25th Apr 2011, 08:25 PM #12Senior Member
- Join Date
- Oct 2007
Nice work on the scarfs
I made myself an 8:1 scarfing jig for my table saw, and I've found that they don't need any further work after running through the saw - ready to glue straight up. I've just today scarfed and glued up the wide staves for my OzRacer mast.
26th Apr 2011, 11:54 PM #13
The scarfs glued nicely and the boards have remained straight. I want to glue them together soon so I can have something to work on--tapering and rounding the boom--while I continue the hunt for yard and mast lumber.
I also would rather have more things ready to glue so that I can maximize the use of the epoxy. I have nice strips for the tiller ready, just need to make the spacers. So it looks like I need to do some wood cutting so I can get on with the gluing that I need to do to in order to get on with wood cutting...
Good thing no one's paying me to do this!
1st May 2011, 05:31 AM #14
Quick update and question. I'm ripping wood for yard and I screwed up (more to follow tonight). Question: can the yard be about 15cm (approx 6 in.) shorter, or should I go through the trouble of scarfing an extension? I'm all ready to do the extension, but I thought I'd do a sanity check first...
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1st May 2011, 01:53 PM #15
We had a glorious day in New Jersey today and I spent it in my yard, working on my yard. Yes, I pulled my power tools into my yard and commenced ripping and cutting the lumber for my upper spar.
I found another nice piece of Oregon at my nearby big box Home Depot, this time with no knots to speak of. Itís actually an end cut, but the tree must have been fairly large diameter because the curvature of the rings is pretty flat.
However, as noted in my previous post, I did screw up one of my cuts. The result is that I will have more scarf joints than I intended to get the full length of the yard. Hereís how the pieces will line up:
I didnít cut the angles for the scarf joints yet, just in case the assembled wisdom here thinks that I should just reduce the length of the yard by 15cm. I doubt thatís going be the recommendation though. As a result of the above-mentioned screw up, the stubby ends are slightly narrower than the other pieces. This is ok (which I should have realized when I discovered the mistake) because the yard gets tapered at both ends, far more than the few millimeters difference in the cuts.
The moral of the story is: donít get distracted by blue sky and sunshine when operating power tools. Bluebirds arenít gonna sail your boat for you, so tell them to take a hike and then focus on the lumber!
There are more pictures and more commentary on my GIS blog...
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