a bit confused about spars

[DanaDCole]

I'm getting ready to order the lumber for spar construction, but that clear wood is expensive and I want to make sure I get it right. The mast is easy enough to understand--1@ 16' 1x12 or 2@ 12' 1x12s scarfed together. I also figured out the bowsprit--laminate two 2x3s together to get a 2 1/2 x 3 piece. The yard (gaff) and boom have me confused though, as follows:

1)The finished dimension of the gaff before tapering is supposed to be 1" x 3", yet the materials list calls for 2x3 lumber, which has a maximum actual dimension of only 2 1/2". I don't see anything in the manual about laminating the wood, and besides, only 24 linear feet is called for, which would give me enough for one boom length and one gaff length. A little less than two feet would be left over--but at least six feet would be needed to fill out the part that has to be between 2 1/2 and 3 inches. And again, nothing is mentioned in the manual about laminating two pieces.

1a) It looks to me like I need a 12 foot 1 x 2, which I would glue to a 12' 2 x 3. This would give me a 3 1/4" x 1 1/2" blank that I would then mill to the required 1" by 3" piece and cut to 10' 1/4" for the gaff. (Actually plan to cut it to 11' to reach the gallows, as Pete (Tattoo) pointed out.)

2) I'm having a similar problem understanding the boom. The finished dimension is supposed to be 2 1/4 x 2 1/4 before tapering the end, but the materials list calls for 2 x 3 lumber, which is only 1 1/2 inches on one side.

2a) So,I will also need a 12 foot 1 x 3, which I would then glue to a 12' 2 x 3. This would give me a 2 1/4" x 2 1/2" blank to then mill down to 2 1/4 x 2 1/4 and cut to 11' 10 3/4" for the boom.

Has this been the experience of those of you who have fabricated the spars, or am I missing something?

[DanaDCole]

i'm realizing now that my post was too complicated for anyone to respond--not that folks are unable to understand the concepts, but that I didn't state them all that clearly. After a message from John Harris (I copied the post to the CLC email address) I understand that fabricating the spars is basically a process of glueing bits together to get the needed dimensions. Much of that depends on what you have available or can get hold of, so there can't be any particular exact materials list. Those who choose to buy the timber package may have an advantage, but it seems to me a very expensive way to go. Or I may end up spending about the same in the end, but at least I can do it piece-meal and I may incur lower shipping charges.

[truenorth]

I haven't responded because I haven't gotten to my spars (and won't until next year) but I'm somewhat familiar with the process having built up trellises and that sort of stuff. Yeah, I think you're overthinking it a bit. Glue (epoxy) it up to spec and cut it down is basically how it's done.

Not sure what lumber you have access to, but even the local Big Box stores have lumber that will work, if you're patient enough to sift through it. They call it "whitewood" or "SPF" for "spruce-pine-fir". It's a bit of a mishmash but you can get some good cost savings. For example, Menard's 1x4x12 clear Select Pine is $9 a board. Those dimensions can get you anywhere you need to go. Pine is really easy to cut with a table saw, even 3" thick. Unused lumber can be used for cleats. The PocketShip near me has all of her spars made from Big Box lumber and it looks and feels great.

[DanaDCole]

Truenorth,

That is extremely helpful. Thanks!

[DanaDCole]

Truenorth,

You were absolutely right. I went to Lowe's of all places (the local lumber guy didn't want to go to the trouble to even look) and found some beautiful, perfectly clear "Select Pine." The only problem is that everything is 1x, so I'll have to glue two 1x6s together to make the keel, for example--but that will probably result in a stronger, straighter keel if I do it carefully. They didn't have anything longer than 8', so I had to buy 8 1x4x8s and a 1x4x6 to get it oup to 16'. I'm going to become really good at making scarf joints! (Looking at the Pocketship pictures I can see where it might not be a problem if the mast was slightly shorter than 16', but I'm not about to mess with that critical part of the design.) I will use a combination of 1x3s to fabricate the bowsprit. This is a bit like plywood--the pieces are laminated to form a better whole.

Given the limitation of 1x and 8', I'm gong to have to sit down with the plans and figure out the best way to fabricate the yard and boom, but that can wait. Thanks again for your insights.

[Dave Archer]

Hi Truenorth,
Just work off of the plans which have all the details that you need. Real easy. Make sure the bow sprit is well made. You will appreciate the stresses on it when you take her out for the first time.

More importantly, build a very strong tabernacle. Use ply and glass inside and out. Make sure that it will fit too? Snug is good but too tight and the mast won't fit into it!

Happy building

[truenorth]

Dana, that's good news that you were able to find lumber that suits your needs. I, too, have found local lumberyards less than helpful when it comes to finding clear softwood. They'll hound me all day if I want hardwood but softwoods "are over there".

On the scarfing, I'm a bit confused. You have a few 1x4x8's which should get you to 1x4x16 if properly scarfed (length needed for mast). You don't have to reduce the length of the lumber, just take off material towards one end in a 1:8 to 1:12 ratio. So if your dimensional lumber is 3/4", your scarf should be 6" long at a minimum, or up to 9" long. This is the distance from tip to full thickness. Am I reading your intentions right? Why are you losing board length by scarfing? I suppose if you wanted to alternate the scarfs so they don't line up, it could be a reason?

Dave, agreed! I'll likely wind up ordering some more 'glass because I plan to overuse it. I have an irrational fear of poking a hole somewhere bad (that was preventable) so most everything is getting a layer just to be sure. Under the cockpit deck is a good example. Lots of 'glass to be used, but also lots of peace.

[DanaDCole]

Well now you have me confused. If I cut a scarf in the end of one board, let's say 6" long, and a matching scarf in the end of another board, then when I put the two together the tip of one board's scarf has to reach the end of the other board's scarf. So I lose six inches in overall length. I.e., two 8' boards scarfed together with 6" scarfs would come out to 15 1/2' in total length.

You are correct about my idea of staggering the scarfs, though. Since I'll be putting a 3' board on each end of each stave, I'll end up with 18' staves, and with some creative cutting no two scarfs will be together. I may modify this some to keep the scarfs high up where the stress is less, but if done properly the scarf joints are as strong as the original wood, if not stronger. Some feedback on this would be helpful.

[truenorth]

Dana, we're turning this into our personal chat room

Gotcha - that makes sense. You'll lose the 6" on the overlap. I'd be working with 12' boards so don't need to think. Thinking is dangerous sometimes!

On staggering the scarfs and/or 'small' scarfs, I have no data, but I do know that John himself has said he's scarfed masts out of 4' boards just to prove there isn't any loss of strength. I think that's in the manual IIRC.

[DanaDCole]

You are right, and it is definitley hard to work these things out in the abstract. I have to make drawings before I dare to order lumber, and still have to hope I get it right. Not too worried about the scarfs being strong enough, but I haven't made them before (glued them, etc., but not cut them from scratch) and will practice on some scraps first. BTW, Sam Devlin's book, "Devlin's Boat Building," includes a lot of valuable information about that and many other aspects of boat building. I highly recommend it, along with John Harris's comments in his manuals, blog, this forum, and his videos.

I got a call from the lady at Lowe's today who said she found a new supplier that guarantees a 16' 1x12 he has to be absolutely clear and knot free. If the price is right I may go for it. It will save a lot of work and I can rip the 1x4s I already bought for plenty of other uses.