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Thread: Making a catboat boom

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    Default Making a catboat boom

    Here's an old mast from some long-gone Alden schooner, or so I was told but it doesn't really matter. It's to be cut shorter and reduced somewhat in diameter.

    The first problem was the getting home part...


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    Default Re: Making a catboat boom

    Is that three-wheeled trailer a custom job?

    I'll put some coffee on...this oughta be good.

    Kevin
    There are two kinds of boaters: those who have run aground, and those who lie about it.

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    Default Re: Making a catboat boom

    Looking fwd to seeing where this goes.

    She's quite the stick, isn't she? Is she a solid spar then? I am hoping this could help me re-round out and beautify the spars on my CY, when I get around to it...
    Quote Originally Posted by Yeadon View Post
    Double-enders are optimistic.

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    Default Re: Making a catboat boom

    Quote Originally Posted by Breakaway View Post
    Is that three-wheeled trailer a custom job?

    I'll put some coffee on...this oughta be good.

    Kevin
    Two wheeled trailer, Kevin. It belongs to a friend of mine, and had been sitting since its boat was launched last spring. The brakes were so frozen that no amount of backing-and-forthing across the parking lot would get them to turn. The determined application of brute force failing to do the job, our last option was to remove the offending pair of wheels just this one time.

    The trip home was made without incident. The mast was unloaded and then stripped of its considerable load of bits and pieces. It was forty-five feet long with a maximum diameter of five and a half inches. The boom to be made will be about twenty-nine feet with a maximum diameter of five inches. The spar had a scarf joint starting about the thirty foot mark, which made the cutting-to-length a little less angsty. It was a nice scarf, though, six feet long and perfectly sound.


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    Default Re: Making a catboat boom

    Quote Originally Posted by bott View Post
    Looking fwd to seeing where this goes.

    She's quite the stick, isn't she? Is she a solid spar then? I am hoping this could help me re-round out and beautify the spars on my CY, when I get around to it...
    It is a nice piece of Doug Fir, Dude, old growth, high ring count, almost clear. It's always good to be able to watch something done before you try it, sort of de-mystifies the process, but, lets face it, there ain't many people doing this these days so you're kind of on yer own. Which suits me just fine.

    Here's the dirty deed done...simple as pruning a pine branch really.


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    Default Re: Making a catboat boom

    Here we are, cut to a rough length and ready to shape. The end in the foreground will be against the mast and will be about four inches in diameter. The maximum diameter of five inches occurs about seven or eight feet from the far end, about where the boom bail will be placed. The outboard end will be reduced to a diameter of three and a half inches.


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    Default Re: Making a catboat boom

    I used to have a pole dinghy..... That would have been the perfect thing for hauling that spar home.... But I gave it to a guy in VT....
    Nice garden by the way.
    (Good talking to you tonight! I'll give you a call in a few days)

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    Default Re: Making a catboat boom

    The grain looked pretty tight on the mast, what could be seen through the old paint. Cutting the ends revealed a nice ring count with a lot of promise of a nice looking spar beneath the paint.


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    Default Re: Making a catboat boom

    Quote Originally Posted by Mrleft8 View Post
    I used to have a pole dinghy..... That would have been the perfect thing for hauling that spar home.... But I gave it to a guy in VT....
    Nice garden by the way.
    (Good talking to you tonight! I'll give you a call in a few days)
    Always good to talk to you, thanks about the garden, 'the hell's a pole dinghy and how long does it take one to go sixty miles??

    Time to don the dust mask and plane off the old paint...see what's under there...



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    Default Re: Making a catboat boom

    A pole dinghy is what they used to use to tow telephone poles from point A to point B with... It's an adjustable "U" bolt with a ball hitch, and an axle (w/ wheels and tires) with a pair of adjustable "U" bolts. You bolt the axle to one end of the pole, and the ball hitch to the other..... Completely, infinitely adjustable..... Also illegal in most places now.....

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    Default Re: Making a catboat boom

    Quote Originally Posted by Mrleft8 View Post
    Completely, infinitely adjustable..... Also illegal in most places now.....
    The illegality somehow adds to the charm of the idea, a sort of outlaw spar-towing caper. I like that, maybe drive it by a police station, fly past a stopped school bus...oh,wait, maybe not that.

    The spar is now blocked in position. In this case the row of holes for the sail track is facing down, although you can't see them here. They will eventually be filled and plugged and covered with the track when it is replaced.

    The center is approximated and a circle inscribed on the end of the spar. In this case the circle is the three and a half inch diameter of the aft end of the spar. With a small pocket level eight tangents are drawn, each representing one of the eight flats to be made in the eight-siding the spar.

    Each end is done, giving you two control points. The only other diameter given is the five inch diameter located about eight feet from this end. You just put a circle around the spar at that point.




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    Default Re: Making a catboat boom

    So it's time to let the fun begin and make the chips fly.

    Don't be fooled by that nice hand plane, that's just for the calendar shot. This was done with an electric plane, as will most of the eight siding. When the flat gets wider than the cutterhead of the plane a little ridge gets left. The hand plane can quickly remove the ridge with more control than the electric one.

    Control is what it's all about here. Controlling the development of the flat. This is the critical step in going from one cylindrical shape to a smaller one. You need a good reference surface from which to measure the other three sides. The flat is planed through the three control points, i.e., the two ends and the maximum diameter.

    A word about planing a taper. It works whatever tool you use, hand plane, electric, even a stationary jointer. You start by taking a pass close to the end. The next pass starts further back and continues through. The third further back still...and so on. This creates a taper by removing more material from the end. The steepness of the taper can be controlled by the spacing of the successive passes.

    Do this carefully, checking with a level every few passes and eyeballing down the length of the spar as the shape develops. You control what you can and the rest is done by eye.




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    Default Re: Making a catboat boom

    Quote Originally Posted by Jim Ledger View Post
    It is a nice piece of Doug Fir, Dude, old growth, high ring count, almost clear. It's always good to be able to watch something done before you try it, sort of de-mystifies the process, but, lets face it, there ain't many people doing this these days so you're kind of on yer own. Which suits me just fine.

    Here's the dirty deed done...simple as pruning a pine branch really.

    You going to get the gaff out of the top end?
    It really is quite difficult to build an ugly wooden boat.

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    Default Re: Making a catboat boom

    Probably too short for the gaff. You could take out a few neighbors with that boom. Do you know the story about the battle of the cove by Howland? (added: either in S'west by West of Cape Cod or The Middle Way) Will the top face of the spar be straight? I think you should start by facing to the 5" dimension and then cut tapers. Ha!
    Last edited by Thad; 09-24-2012 at 01:24 PM.

  15. #15

    Default Re: Making a catboat boom

    Quote Originally Posted by Jim Ledger View Post
    The grain looked pretty tight on the mast, what could be seen through the old paint. Cutting the ends revealed a nice ring count with a lot of promise of a nice looking spar beneath the paint.


    It wouldn't matter how much money, I wouldn't even be able to find a piece of wood like that around here.

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    Default Re: Making a catboat boom

    Quote Originally Posted by Peter Malcolm Jardine View Post
    It wouldn't matter how much money, I wouldn't even be able to find a piece of wood like that around here.
    Peter, if you are in need of some Doug Fir but in a smaller size check out the DF 4"x 4" s at Home Depot. I found plenty with a nice close ring count as shown above and some were nearly clear stock for the full 8' length. I was ready to place an order with my regular lumber supplier but was having a hard time believing I needed to spend $700.00 to obtain enough 1/4 sawn stock to build a small cockpit sole and barndoor rudder for my catboat. I paid just under $100.00 for those Home Depot 4x4s which I re-sawed to give me my 1/4 sawn material. Now, every time I go to Home Depot I'm looking for those good pieces and will pick some for future work as I find them. $11.20 each here in MI.
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    Default Re: Making a catboat boom

    Right you are, George, about the Home Depot fir 4 x 4's. I walk by them every time, and if there's one near the top I grab it. Some are clear, some have a nice high ring count, and at ten dollars apiece it works out to less then a dollar a foot. Checking out the end of the pile reveals some tantalizing prospects buried just a little too deep, but a trip the following week might see them within rech. Spars, workbenches, garden gates,good stuff.

    Peter, you can get that high ring cout Fir in some lumberyards, but you will pay about twelve dollars a foot. We used to make clam tong handles out of 5/4" stair tread, some eighteen footers. Nowadays,though, that's a two hundred dollar plank. You might recall the Copper House cabinets fron a few years back. They were all old growth Fir, most of the wood for the interior of the house was trucked fron Washington state. Somehow a set of tong handles fell off that truck.

    I'm sitting, this morning in my room on the nineteenth floor of the Sloan-Kettering Memorial Weight-Loss Clinic, enjoying a nice view of the East River and the Fifty-Ninth Street Bridge, I have a couple of fresh abdominal incisions that might keep me from lifting the planer for a few days, so there might be a little hiccup in the progress.

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    Default Re: Making a catboat boom

    Jim--all the best for a speedy recovery

    Kevin
    There are two kinds of boaters: those who have run aground, and those who lie about it.

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    Default Re: Making a catboat boom

    Thanks, Kev, waiting for my ride as I type. The Prez is in town today so I might be all recovered before we can get across the bridge.

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    Default Re: Making a catboat boom

    Quote Originally Posted by Peerie Maa View Post
    You going to get the gaff out of the top end?
    Sadly, no, Nick. The leftover piece will, no doubt, be suitable for a smaller spar, or maybe a little flagpole on the boatshed...or maybe a clothesline prop, I can see that happening

    I have a wonderful piece of fir for the gaff, given to me by Doug B, who shows up here occasionally. It's already been four-sided Last weekend I rescued it from its basement tomb...the better to shape it along with the boom.

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    Default Re: Making a catboat boom

    Glad to see you're not lingering for the cuisine, Jim.

    Remind me, what's your plan for the mast?
    We must go too far in order to know how far to go. Yeah.

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    Default Re: Making a catboat boom

    A couple-o-cuts to da belly? Gasp! At a weight loss clinic? EEEK! I hope they don't hurt Mr.Ledger and that you are a robust healer. Have a pleasant and quick recovery!



    Cheers!



    Peter


    P.S., Are you considering roller reefing for your sail,Mr.Ledger? If so, I may have some hardware for the bitter ends of that boom. I just need to know the finished dimensions of the ends to check against what I have. As we say up here, offered at un prix d'amie!
    Do it,do it,do it,do it,do it,do it,do it,now!
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    This boat was built with ten thumbs.No fingers were harmed in anyway.

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    Default Re: Making a catboat boom

    "A few days"? Tracey said that the Dr. said "End of October"..... Don't make me send Carter out there to bite you in the knee caps!

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    Default Re: Making a catboat boom

    My god jim, if they cut you up for a couple of pounds what would they do to me???
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    Default Re: Making a catboat boom

    Johnson sold his soul at the crossroads, so Jim's gotta give his pound of flesh someplace!

    Speedy recovery for you there Jim.
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    Default Re: Making a catboat boom

    Get well Jim. Who else can taunt Donn at your level?

    I will look at Home depot...
    I did buy a nice piece of 20 foot long sitka 2X6 a couple of years ago just because. It was 11 bucks a foot. I still have it.

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    Default Re: Making a catboat boom

    Hey Jim, nice to see your post. Get well, I'll call you in a week or so. Rich

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    Default Re: Making a catboat boom

    Quote Originally Posted by Peter Malcolm Jardine View Post
    Get well Jim. Who else can taunt Donn at your level?

    I will look at Home depot...
    I did buy a nice piece of 20 foot long sitka 2X6 a couple of years ago just because. It was 11 bucks a foot. I still have it.
    Eh-Hem!!!!!
    Not moi, certainly!......
    (And that's spelled "Sitka", with a capital "S". )

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    Default Re: Making a catboat boom

    Quote Originally Posted by Thad View Post
    Probably too short for the gaff. You could take out a few neighbors with that boom. Do you know the story about the battle of the cove by Howland? (added: either in S'west by West of Cape Cod or The Middle Way) Will the top face of the spar be straight? I think you should start by facing to the 5" dimension and then cut tapers. Ha!
    I haven't heard that story, Thad, if you feel like telling it.

    The top face might be a little bit straighter than the bottom, as I would favor it a bit...but nowhere near dead straight.

    Your idea about making a five inch square timber first, before laying out the tapers is a good one, except that there's just not enough wood to accomplish that. If there were I still would not do it because we would be looking at enough wood to make a mast out of the spar instead of a boom. This is a more interesting problem, and one more likely encountered in cutting one spar out of another. Usually, you will find yourself trying to cut a slightly smaller diameter that will not allow you to take it back to square and follow the textbook instructions.

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    Default Re: Making a catboat boom

    Quote Originally Posted by Rich Scheffer View Post
    Hey Jim, nice to see your post. Get well, I'll call you in a week or so. Rich
    Thanks, Rich, call anytime. Always a pleasure.

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    Default Re: Making a catboat boom

    I understand about lacking the material, but I would still approach it that way. The battle of whatever cove story is about interlopers in a scallopers "territory". A jibe of the catboat boom seems in my recollection to be the only blow of the "battle", taking the superstructure off the other boat. Easy. One swipe.

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    Default Re: Making a catboat boom

    So.... Jim.... We're all sure you can make a catboat boom....... But do you think you could make one thrum?...... Or whirr?

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    Default Re: Making a catboat boom

    Jim, Beautiful piece of wood, does the grain orientation have any bearing on the final stepping of the mast? Seems to be about the same above and belaw the scarph. I guess those old guys had a plan. Rich

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    Default Re: Making a catboat boom

    Quote Originally Posted by Rich Scheffer View Post
    Jim, Beautiful piece of wood, does the grain orientation have any bearing on the final stepping of the mast? Seems to be about the same above and belaw the scarph. I guess those old guys had a plan. Rich
    Yanno, Rich, a guy can waste a whole lot of valuable time pondering why old-timers did this or that from the scant clues left behind hidden under layers of paint or scribbled pencil notes on the back sides of ripped-out baseboards. Nonetheless your question had me running outside to check the grain orientation. It runs at about forty-five degrees to the boats centerline, so make of that what you will.

    Anytime you glue two pieces of wood together it's probably best to glue flat-to-flat or rift-to-rift, and so forth, so the expansion rates of the pieces are equal. It's not always possible when edge gluing planks, but when you're scarfing two six-by-sixes it's very feasible.

    My take on the grain orientation is this...they scarfed and shaped the mast, it probably wasn't perfectly straight, as often happens, and then they cut the heel tenon to orient the curve fore-and-aft.

    It's as good a guess as any.

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    Default Re: Making a catboat boom

    Looks like you have enough for the gaff as well. This boat is one of the few that benefits from heavy tophamper and I know from Marmalade that you can hoist that big sail even with a solid gaff.

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    Default Re: Making a catboat boom

    Jim, just like steam bent frames, or tong handles, grain direction is very important. I dont know much about stress loads on a sailboat mast, but I would hate to find out that they used to orient the mast grain in a particular direction, for a reason. If you run into Doc Jones [not the chriopractor] lets get him to run us back a century or so in his time machine, we could ask Gil Smith, I bet he would know! Rich

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    Default Re: Making a catboat boom

    Let's recap...

    I'm making a spar out of a larger one, a boom, in this case, out of a mast. Most times when you need to reduce the size of a spar, the timber is not large enough to take back to a square section, and a good thing too, as this would result in an enormous waste of wood and effort. The usual case is to remove only a small portion of the diameter.

    The problem is, therefore, how do you make a straight, correctly tapered spar out of an out-of-round, crooked spar of the wrong taper. You could just have at it and let the chips fly...and if you're long on experience...or just easily pleased, then this might just work for you... a couple of chalk marks, a good squint down the length, spit in your hands and rub them together...

    But this is a valuable piece of timber and deserves a few pleasant days fussing over (actually, if you count picking the stick up, I'm already over that limit by one day, more if you count finding it).

    To begin, again...here's is the timber, cut to rough length. A flat has been planed onto what will become the bottom of the boom. Remember, there are three control points, the two ends, and a spot about eight feet from the far end which will end up a five inch diameter. This spot is just about five inches already, so very little wood will be removed there. With the timber chocked, the flat is trued to level with the plane. The flat has been eyeballed to the taper needed, leaving a little bit to fool with later on. It's important to fuss with this step because everything that will follow will reference off this surface.

    Last edited by Jim Ledger; 10-22-2012 at 10:56 AM.

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    Default Re: Making a catboat boom

    Quote Originally Posted by Ian McColgin View Post
    Looks like you have enough for the gaff as well. This boat is one of the few that benefits from heavy tophamper and I know from Marmalade that you can hoist that big sail even with a solid gaff.
    Ahoy, Ian! No, that cut off piece isn't nearly big enough for the gaff. Luckily though, I already have a suitable stick for the gaff, waiting just outside of camera range for it's own turn to get shaped.

    The next logical step is to get some kind of reference line down the center of the flat. A string stretched the length of the spar, followed by inking a line does the trick. It's good to remember that this line is the outside surface of the finished spar


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    Quote Originally Posted by Rich Scheffer View Post
    Jim, just like steam bent frames, or tong handles, grain direction is very important. I dont know much about stress loads on a sailboat mast, but I would hate to find out that they used to orient the mast grain in a particular direction, for a reason. If you run into Doc Jones [not the chriopractor] lets get him to run us back a century or so in his time machine, we could ask Gil Smith, I bet he would know! Rich
    Rich, I'd like to ask Gil Smith how they used to get that sweet tumblehome on the aft end of those Patchogue River oyster boats, or watch him steam those oval coamings. As for the grain orientation in mast scarfs, I suspect it had to do with getting equal expansion in both pieces by gluing them flat-to-flat, or rift-to rift and so on.

    All things being equal and good, that stretched string in the previous picture ought to lay dead center down that carefully planed flat. Here though, is the situation about halfway along the spar, the string is way off center. This is because the mast was crooked. The rigging can straighten a crooked mast to some degree, but a boom is a free standing object, and unless we want the boat to perform better on one tack than the other we will need to straighten it out. The inked line is the first step to this end.


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    Default Re: Making a catboat boom

    For the time being the crookedness is of no importance to us as we flip the boom over and plane in a flat on the opposite face. The reason for the care taken getting the original flat true becomes obvious now as the second flat is developed off the first. A few passes are taken with the power plane, followed by a truing-up with the hand plane down the length of the spar. A small out-of-squareness can be seen here, the high side marked with an "X", then another measurement taken a couple of feet down and marked, all the way to the end. You take a little bit off, and square it up, take some off, then square it up, never letting the shape get away from you.


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    Default Re: Making a catboat boom

    The third and fourth sides are planed flat in a similar manner, truing up using a square directly on the original flat. It's important to realize that I'm not going all the way to my final dimension on these three flats, only getting them square to one another. The idea is to get another centerline on an adjacent plane which will allow the opposed flats to be measured and planed equidistant from the line at all points along the length of the spar. Easier to show in pictures than explain, actually.

    But that's for another day. Good night.

    Last edited by Jim Ledger; 10-21-2012 at 10:39 PM.

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    Default Re: Making a catboat boom

    At the end of the afternoon we're left with this...a not-very-well tapered stick with four flats square to one another. Striking an additional centerline at right angles to the first, as seen here, gives us a a reference in the other axis. From here it will be possible to taper all four sides to equal dimensions. The spar is in there somewhere, the lines will indicate just where material has to be removed.


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    Default Re: Making a catboat boom

    Nice to see you back at it.
    Beware of that little level yer using though..... Don't just leave it lying around..... Torpedoes have been known to sink boats......

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    Default Re: Making a catboat boom

    [QUOTE=Mrleft8;3570419]Nice to see you back at it.
    /QUOTE]
    Seconded, and I hope that you are feeling just fine and dandy.

    Jim are you able to use winding sticks to any advantage here?
    Steve Martinsen

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    Default Re: Making a catboat boom

    Quote Originally Posted by SMARTINSEN View Post

    Jim are you able to use winding sticks to any advantage here?
    Thanks, Doug, Steve. Feeling good, sort of.. the doctor said not to lift anything over ten pounds for six weeks and I doubt that plane weighs more than five, even so after about a half hour I have to stop for a minute or two.



    Winding sticks would certainly work instead of the little level, although they might involve much hiking up and down the length of the mast, hunkering down and squinting. But, sure, if you forget the level at home (and who hasn't?) go for it.

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    Default Re: Making a catboat boom

    Okay, to recap...
    We've planed four flat faces, square to one another...

    Two adjacent faces have centerlines drawn on.

    Moving on now. There are two tapers on the boom, a long shallow taper from the five inch diameter to the four inch diameter about twenty-two feet away, and a steeper taper from the five inch diameter to the three-and-a-half-inch end about eight feet away. Both of these tapers were laid out with chalk lines on the floor and their widths taken every two feet. They were recorded on the notepad in the photo.

    The photo illustrates the measuring of a half width, in this case two and a sixteenth inches. The mark made represents the wood to be removed from the left hand vertical face. After making similar marks every two feet the spar is rotated one flat clockwise and planed to the marks.


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    Default Re: Making a catboat boom

    With reliable marks drawn on the spar the waste can be planed off with confidence. It should be empasized here that there is no eyeballing going on in this operation...well, maybe just a little. The waste is being removed to measurements off a centerline, which will produce the correct taper without guesswork.

    Here are the four sides planed off. Naturally, the centerlines were planed off and the lines seen here are freshly made lines put back on after the planing operation.


  48. #48
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    Nov 2006
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    Default Re: Making a catboat boom

    After fussing with the squared-up spar, knocking off a few high spots and smoothing it out a bit, it's time to go octagonal. Here's the eight-side jig in action. This particular beast scratches two lines into the surface, which can then be highlighted with pencil, as seen here.


  49. #49
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    Default Re: Making a catboat boom

    Before we get to the eight siding, I'd like to show a picture of what's happening about halfway down the boom. The butt end of the stick squared up nicely, but as we get closer to the maximum diameter there isn't enough material to square, so you're left with a situation like this...a more octagonal section.


  50. #50
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    Nov 2006
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    Default Re: Making a catboat boom

    The eight siding can be roughed out with a router. While you can't go all the way to the line, due to the changing depth of the chamfer, you can remove a lot of the waste quickly and establish an accurate plane for further development of the bevel with power and hand planes. This is a good setup, a large chamfer bit with the bearing removed, using a fence to guide the cut.


    This is the extent that the router would easily remove material. The ends of the spar will be left square temporarily, the inboard end in order to facilitate fitting the gooseneck, and the outboard end to allow a mortise to be made for an outhaul sheave.


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