Midstation marks

Right now, with the deck plan in hand, you need a benchmark from which to plot your boundary stakes. Lay a straightedge across the hull from sheer to sheer, with one edge exactly centered above the 'midship station mark on the top of the keel. As shown in Figure 13-3, stretch a string from the center of the stem to the center of the sternpost to get the a thwart-ships center of the straightedge. Measure from this point, port and starboard, to the outside of the planking, and be properly proud if she proves to be no more than an inch wider on one side than on the other. File this information in the back of your mind, or in your notebook if you must, and go on to your main objective, which is to spot, two points on the straightedge exactly equidistant from the center, and as far out as is convenient—right at the sheer, probably. Now hook your 50-foot tape or non-stretching wire to the exact center of the after figure 13-3

Mid-station marks established at the gunwales for purpose of laying out deck timbering

figure 13-2a

Clamp timber at the bow

in the powderhorn region

figure 13-2b

To scribe down a deckbeam face of the stem, and proceed to adjust the straightedge until the two points on it are equally distant from the stem, even as they remain equally distant from the center. Check your marks with a plumb bob, from the station mark on the keel; then nail the straightedge to the sheerstrakes, so that it'll stay put while you lay off all your longitudinal distances from it.

Mark these essential longitudinal distances— the ends of the cockpit, the ends of the house, the forward hatch, the centerline of the mast, the chainplates, all of the deckbeams—on the sheerstrake and on the top of the sheer clamp, being very careful to indicate on which side of the mark the beam is to be placed. It's embarrassing indeed, as I've found on several occasions, to discover that you've fitted, and fastened, a beam forward of the mark on one side and aft of it on the other. Ah, well—unless a bulkhead lands there, probably no one will notice.

Cutting and fitting the deckbeams

Now, armed with a tri-square with a bubble, dividers with a pencil leg, crosscut and rip saws, chisel and mallet, you are ready to mark, cut, and fasten the main deckbeams, if you have any handy. I blithely assumed a while back that you had a proper beam mold to use while dressing the sheerstrakes fair for the underside of the deck and for marking for the height of the sheer clamp. Use this pattern to mark those fine, sweeping planks you saved out, so that the grain follows the crown of the beam (5 inches of crown in 10 feet of length, or whatever your designer calls for).

I always saw out deckbeams with a light-gauge, well-set, sharp 10-inch table saw or (rarely) with the ubiquitous 7V2-inch portable electric circular saw. Either of these tools does a smoother job than the handsaw. Check the sawn beams carefully against the pattern, because they may change shape after sawing.

If you lack sweeping stock to make sawn beams, you can steam-bend straight stock on a form, over-bending enough to retain the proper crown when you take them off the form. Or you can glue-laminate the beams over forms with five plies of a wood that glues well—a process much loved in these times because, we are told, at last someone has come up with a way to make wood a satisfactory boatbuilding material. I almost wrote Viable Alternative instead of satisfactory; if I did, I would have put a trademark symbol after the term I druther

Deckbeam

Plumb mark

Deckbeam

Bubble centered

(a) Plumb the terminals of the cuts to be made on the molded face of the beam.

Plumb mark

(b) The other side of the beam stave is plumbed similarly, in order to obtain the sided bevel of the butt as well as the sided bevel at the clamp.

Plumb marks made in (a)

saw ihem out, myself. Maybe they won't be

compatible with the Space Age, but they'll be good oak or locust, and will hold fastenings forevermore, and won't delaminate, no matter what.

Set up staging inside the boat to match the outside staging to make the sheer about belly-button high when you climb aboard with your tool kit and one of your long beams. Lay said beam across the boat, on top of the sheer planks, exactly over the spot it will drop to after you've cut it to length. Clamp the beam somehow-, so it can't shift position.

Look at Figure 13-4 and proceed to mark for the end cuts: Plumb up from the inside edge of the sheerstrake to the top of the beam; plumb up from the inside top corner of the clamp to the bottom edge of the beam (and a little higher); set your pencil-bearing dividers lA inch less than the plumb distance from the top of the sheerstrake to the top of the beam; and scribe a line at this distance, above the top of the sheer clamp, on the forward and after faces of the beam. (The "lA inch less" is not introduced to allow for errors, but rather to allow you to set the beam into a notch of that depth on the sheer clamp.)

deckbeam and sheerstrake.

Scribed line

(f) Beam in place

(d) Scribe the stave's width while holding the scriber parallel to the plumb line (do this on the other side, too).

(e) Trim the beam along the molded and the sided bevels marked.

(f) Beam in place

Scribed line

Right angle cut with the scribed line

Scriber is set here (distance the stave is to be dropped).

Make this scribe W less than the "drop distance" if the finished beam is to fit into a W notch in the clamp.

Fore deckbeams

Centerline of deck plumbed up from keelson marks

1x4 nailed flat across the boat, from clamp to clamp, with edge on station mark plumbed from the keel

1x4 post set plumb to the inside edge of the carlin as determined for that station on the plan

Bridge deckbeams

Carlin stave laid on the deckbeam at either end and clamped to the posts in between

Scribed and snugged down

Fore deckbeams

Carlin Deck Clamp

Now mark, on the side of the beam, the angle of the end cut from the plumbed-up mark at the top, down and parallel to the inside of the sheerstrake. Then mark a line on the top of the beam, parallel to the top edge of the sheer-strake. Tread softly to the other side of the boat and go through the whole process on the other end of the beam.

Put the beam down on the staging, kneel on it, and make the following three cuts: (1) end cut with a crosscut saw; (2) underside cut with a ripsaw, working to the scribed lines on the fore and aft faces and stopping at the mark plumbed

Deckbeam mold

^ Carlin in place

Deckbeam mold

^ Carlin in place

Clamp

Future short beam up from the corner of the clamp; and (3) a little sloping cut to free this piece.

You can now try the beam in place. It should stand lA inch too high, and this amount you'll cut into the top of the clamp, so the beam will drop down just flush writh the sheerstrake and with a little jog against the inside of the clamp.

I'm happy that's over with, and that I don't have to struggle through those directions myself; but you're lucky to have Sam Manning's drawings to go by. Please hark to my warning that there are no shortcuts, yet rest assured that you'll be able to mark one of these beams in two minutes, automatically, with one eye on the bubble, after you've done three or four.

Is this not dreary stuff? Fussv, tedious moves advancing little toward this fabric's final soaring beauty. But when the beams begin to drop into place—one, two, three, without a miss—you can be very full of joy for a while.

Go ahead and fit all the full-width beams: after and forward ends of the cockpit, after end of the house, middle beam in the bridge deck, forward end of the house, and all the beams in the foredeck. Use the beam mold to make sure you don't have a maverick in the bunch, and fasten them all to the clamps—one Vs-inch bolt, each end, countersunk, dead center, down through the center, with nut and washer on bottom.

The breasthook, quarter knees, shelf, and blocking will come later. Right now you must install the fore-and-aft carlins that establish the edges of the cockpit and the house. This is the trickiest part of the deck-frame project, and takes some planning.

Your construction half-breadth plan should give the half-breadth of the house from the fore-and-aft centerline at every station. Nail a

straight one-by-four on top and on the flat across the hull from clamp to clamp at each station. Stretch your string again and mark exact centers of all these temporary cross members—and while you're at it, the centers of all the beams you have so far installed. Lay off on the end beams and on these horizontal flats the widths to the inside of the carlin. Now at each of these marks fit and fasten a plumb post, inboard of the mark. Lay your beam mold against each in turn, as in Figure 13-5, and behold—the inner top edge of the carlin has to land exactly at Point X; you have a fine row of posts to spring the carlin around and clamp against.

figure 13-6 Carliri at deckbeam

Fasten blocks on top of the end beams where the outboard edge of the carlin will lie, and bend the timber around the posts and on top of the end beams. At this stage of the proceedings you'll want the loiuer edge of the timber to land on the crown marks. Use your tri-square to mark for the end cuts on this timber just as you did on the deckbeams: plumb up from the point where the top of the carlin will land. This point will be Vz inch into the face of the beam to allow for a sloping notch (see Figure 13-6).

Figure out the rest of the angles and cuts from the drawing, remembering always that this plumb business works at both ends, unfailingly, and that any deviation from it spells

Sheer curve in the cockpit carlin

disaster. Cut the sloping notches in the beams, cut the ends of your carlin timber to match, and spring it in. Push the carlin down and clamp it with the top edge at the crown marks on your temporary posts; drill for and drive three galvanized 20d spikes at each end through the beam and into the end of the carlin (see Figure 13-6).

Go aft now and fit the carlins for the sides of the cockpit. These are usually straight fore and aft, but they must be dipped in profile to match the sheer. This shape can be determined by the same method outlined above; or you can run a batten on top of the bridge-deck and the after-deck beams, alongside a piece of pattern stock dropped into the notches in the main beams. Mark a fair profile on the pattern. Saw to the line, and mark your carlin timbers from it. Saw them out and install as above (see Figure 13-7). You are now readv to fit the short beams.

Lay out the short beams carefully, square to the ceilterline, exactly opposite each other port and starboard. You'll be happy you did when you install bulkheads, hanging shelves, and deck eyebolts. You will, of course, perceive that the top of the carlin must be dressed off to the crown of the deck. You can do this now or put it off until all the beams and tie-rods are holding the carlin against your attack, but if you choose to defer dressing off, you must be wary of one small effect: Unless you shim up the outboard end of the beam (at the sheerstrake while marking them) to match the incorrect height above the carlin, your marks will be wrong, because one end will have to drop that small bit more than the other to achieve its final resting place.

The boatbuilder's lot is hard enough without adding any avoidable complications, so let's dress off now. Saw off the posts to let your plane go by (you'll have to depress them before you lav the deck, so why not now?) and dress off

the top of the carlin to match the deck crown.

As you fit all those short beams, remember to plumb up from a line Vz inch in from the edge of the carlin, the top of the sloping notch; from the inboard edge of the sheerstrake (to give the top of the beam at the outboard end); and from the inboard edge of the sheer clamp— and to scribe up from the clamp with dividers set V'-i inch less than the distance the beam must be dropped (see Figure 13-8). Fit half a dozen beams, tack them in position with 5d box nails, and drill and fasten them all at once. I like to use two or three 20d spikes from the carlin into the end of the beam, and a bolt through the sheer clamp, as you did on the ends of the main beams.

Short beams joined to a carlin

Short beam stave positioned for scribing down

Note that this untrimmed shoulder must be compensated for by shimming the opposite end, if the plumb and the scribed lines are to be accurate.

Carlin not yet dressed off on the top face

Carlin

Short beam Clamp

Bungs

Carriage bolt through clamp

Bungs

20d spikes

Beam shelf

Scarf joint in a plank shelf figure 13-9b figure 13-9b

Carlin Deck Clamp

Built-up shelf with staggered joints

Bevel change, bow to stern, where shelf fays against the clamp

The beam shelf

Now let's consider the beam shelf. This bit of furniture is a flat stiffener fitted around the sheer under the deckbeams, against the clamp. It can be sawn to shape from several pieces scarfed together (Figure 13-9a), or it can be built up with four or five narrow pieces, say 1 V2 by 2 inches (Figure 13-9b), sprung into place, and through-bolted to the clamp and the deck-beams. The shelf may go the entire length of the boat, or it mav extend onlv a few feet for-

ward and aft of the main chainplates. Whatever its length, it must be fitted on its outboard edge to a constantly changing bevel on the inboard face of the clamp.

If you are working with fairly heavy timber for the shelf—for example, a plank 2 inches by 12 inches by 14 feet long, to produce a 2- by 5-inch shelf with a scarf at each end—you will be wise to take a spiling on a light, curved spiling board and note the bevels at 2-foot intervals. You can transfer the shape from the spiling board to the stock, and saw the shelf out and bevel it to a fit that is fairly close before you ever take it. aboard the boat. Clamp the shelf in place, scribe for the final fit, remove it, dress to the marks, and bolt it solidly to the beams and the clamp. (There is, of course, the possibility that some adjacent beams might not be exactly the same depth. If you can't stand frustration and don't know how to use invisible shims, you shouldn't be in this business.)

With the beams and shelves in place, you can install the tie-rods. These are very important strength members, especially needed under a caulked deck, and especially valuable as the big guns against those sharp-eyed critics who fret about your cheap fastenings from the car-lin to the beam ends.

Get out your long Vs-inch drill, choose likely spots—about 18 inches from each end and no more than 3 feet apart through the rest of the length—and proceed to drill holes through the carlin, the shelf, and the clamp (Figure 13- 10a). Countersink for the nut and washer, of course, on the inboard face of the carlin.

An alternative is to run the rod above the shelf and the clamp, out through the frame and the sheerstrake (Figure 13-10b). This system gives the tie-rod a better angle—one that will make the rod more closely parallel to the line of the deck, that is. This system will require more, and still more, higher bungs in the sheerstrake. It's a toss-up which way you do it.. Just be sure the rods are square athwartships, or you'll be in trouble when you fit the bulkheads.

Rod run above shelf and clamp

Chichen Itza Para Colorear

TiHftm

Finishing the deck frame

What more must be done before you can cover all this with something watertight? Not much, just the breasthook; quarter knees; cen-terline blocking between all the beams in the foredeck, the bridge deck, and the afterdeck; blocking to take bolts from the gallows frame, the mainsheet horse, and the quarter cleats; the under-deck bases for the lifeline stanchions, the anchor windlass, the mooring cleat, the backstay fittings, and the eyebolts—and a few more that you'd better pre-plan before you start laying the deck.

Start with the breasthook. This, in my lexicon, is a block of durable hardwood with its bottom surface fitted to the tops of the sheer clamps, the ends fitted tightly against the sheerstrakes, and the forward (short) side fitted against the after face of the stem. The breasthook grain must run athwartships. The top of the block must be dressed off to the line of the underside of the decking. I usually edge-bore this piece before installing it to take one bolt from the midpoint of the after edge through to the forward face of the stem. Drive two bolts on each side down through the sheer clamps, and four good screws on each side from the sheerstrakes into the breasthook—and you can be reasonably sure that the nose of the vessel will stay together (Figure 13-11).

With all your tools up at the bow, you might as well fit the centerline blocking back to the forward end of the house. This blocking need not be the full depth of the beams, and it may vary in width to accommodate whatever deck furniture will be sited over it: a wide-based windlass, the staysail boom pedestal, the king-

plank, or the butt joint in plywood decking. Also fit a good plank, wide enough to take the widest-spaced bolts in the windlass, with the forward end against the stem, underneath all the beams and back to the hatch opening in the foredeck. Your big bolts from the mooring cleat, the bowsprit socket, and so on, will go down through this plank and tie everything together. Naturally you must fit chocking between the blocking and the plank so you'll have solid wood to tighten against.

Move your gear aft and install the quarter knees. These are invariably shown as beautiful grown crooks, dead-fitted to the transom frame and the inside of the sheerstrake, and presumably bearing upon and bolted to the after ends of the sheer clamps. I prefer to tie this corner together with a big hunk of fore-and-aft grained blocking, partly because I lack such crooks. As shown in Figure 13-12, it must be bolted to the clamps, pinned to the transom frame, and screw-fastened from the sheerstrakes, and it must have enough area to take all the odd fastenings from the covering boards, the toerail knees, and all the other things that come together at this busy corner.

I almost dare suggest that the end is in sight.

Locate, fit, and fasten the blocking to take the lifeline stanchions. Ditto, ditto, ditto for the gallows frame, the mainsheet horse (tie this one under the beams, something like the mooring-cleat technique up forward), the backstay fittings, and the jib-sheet track—grain fore-and-aft on all.

Put some posts from the keel to the underside of the main beams, and smooth everything off ready for the decking. As for me, I'm going sailing.

Plywood with rabbeted covering board

Plywood with rubrails

Canvas over tongue-and-groove

Sprung pla n

Straight-laid plank

Herringbone layup

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