The side tanks, as some call those watertight benches running lengthwise on either side of the cockpit, are next. The first thing is to assemble a basic frame work of 3/4" square stock to support the plywood panels making up the 'tanks'. The plans provide all the measurements, yet this is still a moderately challenging job. Symmetry, port and starboard, is something to concentrate on, along with the fact that essentially square cabinets need to interface with a rather curvaceous hull. From a standpoint of personal satisfaction it would be nice if these joints come out tight, but really it matters little. Epoxy fillets and glass tape will cover it all up. If we aspire for more, though, it might be time to introduce the subject of spiling. This is another essential boat builders term, up there with lofting in importance, yet almost as esoteric these days.

So what's going on? Spiling involves turning out a perfect joint, whether straight or curved, long or short, between two pieces that are unable to lay against each other for marking. For boats this relates mainly to planking up a hull, for which a whole world of spiling skills are needed, most of which only truly can be obtained by years of apprenticeship. We are thankfully not planking here, yet a short exercise closely related to spiling might be beneficial further down the road.

Grab a piece of that 1/4" marine ply, 8' long and more than wide enough to cover the inboard vertical face of, say, the port side tank. Clamp it in place against the framework with the aft end square against the aft bulkhead. 8 feet of stock will not quite reach the forward bulkhead, but let's not worry about that right now. The plywood will hover away from the curving bottom of the boat except at the aft corner, yet we need it eventually to lay tight along the whole run. Measure the widest gap plus 1/2". Make a spiling block of scrap ply as long as this measurement by 1" wide. While holding the block perpendicular to the bottom edge of the plywood and one corner of it against the cockpit sole, mark the future tank side clearly at 8-12" intervals along the full length.

Take the marked piece to the bench. Tap finish nails at each spiled point and spring a batten. Draw the resulting curve and cut. Stick back in boat and discover hopefully a good fit. Repeat the process with the missing forward section, but leave the end a little long so the butt joint can be worked out later. Practice with a piece of cheap plywood, If unsure about the exact method described here. Master this relatively simple maneuver, and we can approach all sorts of curved fit problems with possibly a little less trepidation.

At this point we might want to make up our mind about access points to all the valuable storage these side tanks offer. It can be done simply (round plastic screw-in hatches) or elaborate (shop made hinged and latched lockers). The pictures show one way to do the latter, with the addition of a fancy laid deck type bench top. All in all this added weeks to the construction time, but if we like what we do, why rush it?

After a few distractions, such as stringers and fillets here and there, time has come to focus on one of the remaining biggies: The center board and its cantankerous case. In the old days (read: pre-epoxy) the latter piece of joinery was a source of near constant leaks. Now we use dimensionally stable plywood and smother all joints in liberal amounts of E stuff, and life is a lot simpler, and drier. Yet there's still challenging aspects to consider. The board needs to operate smoothly within the case, preferably without being too sloppy, and the pivot point must be in the exact spot. On top of that, the case needs to be strong, level, plumb and the right height to provide a landing for thwarts and decks. So, concentration in layout and planning is prudent.

I built the board first. One way to do this is how the plans tell us. Another is what I did. The Core Sound followers hesitate to recommend my method, so I will not go in great detail here. The board is made of 3 layers of 9mm plywood, laminated with the grain in the outside layers running lengthwise and the center layer perpendicular (but, we interject, plywood doesn't have just one grain direction. True, but there's always an odd number of plies, with greater resistance to bending awarded to the majority). The leading edge and top piece is solid fir, and the whole affair is wrapped in 12oz biaxial fiberglass cloth. The result, I believe, is massively strong and should not warp. Enough said.

Size the case after the board. Serious racers speak of 1/16" clearance on the sides, while I opt for something less rigorous. Chances are that either the case or the board is not put together completely flat. It doesn't take much wavering to gobble up 1/16", and then we have a board that binds. Annoying at best. Also a hard one to fix after the fact. Better to go with an 1/8" all around.

The inside of the case is subject to abrasion from the board. This is slowly adding up over the life of the boat and with everything epoxied together you will never again be able to service this cavity effectively. Add a layer of fiberglass to these surfaces to slow the wear.

When slicing the big slot in the bottom of the boat, triple check the measurements and the plans. I only double checked and put the hole 3" forward of the desired place. Bummer. If we look at the plans it is obvious what happened. I erroneously used the mast step measurement.

Dry fit and check everything rigorously. Establish a way to clamp the thing in place and hold it dead plump at the same time, then mark the position of the case clearly before gluing.

Sanding. In any boat building project there's hours of this tedium, but when dealing with epoxy in the quantities we do here, sanding seems everpresent. So how do we attack that tenacious material? Rule #1 is to leave it alone until completely dry. The difference is huge between sanding what is perceived to be dry epoxy and the actual fully cured stuff. If the sandpaper gums up right away or we are producing granules instead of fine dust, wait. In a damp and cold shop the chemical process can take a week or more. Dust from improperly cured epoxy can cause the dreaded skin sensitization, another reason to hold off. One more note from the chemical lab: If the epoxy fells like someone smeared our favorite handlotion all over it, we have amine blush. Wash with soapy water before proceeding.

The machines make a difference too, off course. I have not tried every sander out there, but I've certainly used lousy ones and absolutely excellent instruments. Avoid the 1/4 sheet palm sanders. Although cheap and widely available, epoxy is too much for them. Belt sanders, on the other hand, are very aggressive. Having one would be nice, but they are expensive, heavy, and prone to ruining the project instead of steering it toward completion. My current arsenal is simply a handy 5" random orbit for general sanding, and a niche product called the Fein MultiMaster. This oscillating mini sander was first thought to be merely an added luxury to an already too big collection of tools, but has proved to be the ticket for ply/epoxy boats with all their fillets and hard-to-reach corners and cavities. Finally there's the trusty low-tech approach of hand sanding, which I actually use at least as much as all the machines combined.

The sanding jobs involved with this boat are largely in two catagories: Cleaning up spills and drips, squeeze-out and messy fillets. And second, sanding large areas of coated and sealed plywood and glass prior to painting and varnishing. The first chore can be minimized by neatness, improved filleting skills and meticulous cleanup while the epoxy is still wet. Still, hundreds of little imperfections need to be smoothed out. Enter Mr. Fein and his little triangular 60 grit pad.
For the big expanses, if done well, a little hand sanding with a folded piece of 80 grit paper should do. But more likely, the random orbit crew must be brought in. Be careful though. Those 3 coats of epoxy, laboriously applied, can be turned to worthless dust in a few seconds. Use a light hand, finer grit and always hold the pad flat on the surface.

The masts rely on a step to keep the butt end in place, and socalled partners where the spar passes through some structural framework on the boat. Figuring out where all this happens is a tricky endeavour. A lot is at stake here, from performance to in-your-face visuals. First off, they should go exactly where designed. Furthermore, the sticks are raked aft at 3 degrees and they must be parallel to each other, in two planes. A half inch error at deck level translates to many inches at the masthead. .

The starting point is a level boat. Atwarthship is simple, and already discussed in the previous article. Fore and aft need to have the bow 10" higher than the transom. Rig a string line super taut from the stemhead over a 10" spacer block on the transom top. Hang a little line level and get the boat positioned right. Leave the line up.

The plans indicate where the vertical centerline of the masts cross this line. Also we are told the 3 degree mast rake translates to 1" in 20". That's all we have to work with, but it's adequate. Hang a plumb bob from the ceiling crossing the string line at, say, the mizzen location and hover right over the keelson. The true step is some distance forward of here, due to the rake. Measure the vertical distance from keelson to stringline and multiply this by 0.05 (the rake per inch: 1 divided by 20). The resulting measurement is the location of the mizzen maststep forward of the plumb bob. Mark clearly and repeat at the thwart, which would be handy to have built by this time. Using the same procedure establish the step and deck hole for the main. Then complete the job with the reefing step for single mast sailing.

Now for the construction details. These are most complicated in way of the main mast, so let's investigate that area. Deep inside the forward bulkhead space we have already put together the jetplane looking contraption that forms the foundation of the step. It is securely glassed in place, with massive fillets and the heaviest cloth lying around the shop. Neatness doesn't matter too much down here in the dark recesses of the forepeak, but integrity does. Also the framework supporting the front deck is done, but just temporarily screwed together. With the center of step and partners marked, it is time to decide how keep the bulkhead space dry while penetrating the deck with a 3" hole. The preferred method, which we will use, is to permanently install a hollow tube from deck to keel, into which the mast is inserted. A small diameter pipe leading from the lowest point and into the cockpit drain the tube of incoming water, and prevents the inevitable decay this setup is prone to. How to make this tube depends on the mast material. Aluminum requires the method described in the plans, but since this boat will have wooden sticks I used PVC pipe with an inside diameter of 3".

Time to mention painting. It might seem a little premature, but with a complex project such as the CS17 it can be beneficial to paint certain areas early on when access is convenient, before decks are built and hardware and parts installed. I divided this huge chore into three stages: Inside bulkheads and storage compartments. All of the cockpit area up to the coaming. And finally decks and hull. I also did them in that order.

Those lockers are simple and low stress. I used bright white oil based house paint and primer and applied two coats with a cheap brush without much fuss, since even the most discerning gawker should be able to overlook drips and runs in these dark recesses.

For the cockpit area we need a different approach. It is assumed, off course, that we have already sealed all surfaces with a minimum of 3 coats of epoxy, sanded them to perfection followed by rigorous dusting and vacuum'ing and finally been able to enter that rare state of infinte patience required to do a good job. In other words, we are ready to invest the better part of a week kneeling inside the boat with brush and can, first priming and sanding all those inside corners and hard to reach areas, then topcoating until done. This point of apathetic exhaustion will likely arrive before perfection is achieved, but sometimes enough is enough. As a techical side note it should be mentioned that I used System Three's waterbased epoxy paint and primer, applied with 3" foam brushes. I did the work in the dead of winter inside a hermetically sealed shop with a roaring wood stove in the corner. Not an environment favoring volatile solvent based compounds, or else I could have used the excellent Kirby line of traditional paints. Both products have their annoying idiosyncracies yet are highly recommended.

The deck and hull will be painted later.

More things to keep us busy include the deck framing and decks (simple stuff), the construction of rudder, rudder cheeks and tiller (moderately fun, especially the tiller) and cockpit coaming. The latter is a chance to flaunt our work, in fact the aforementioned onlookers will regard this crucial component with particular scrutiny, so we find the finest stock laying about the shop, sharpen our tools and set to work. A coaming with curved laminated corners is the most elegant and not overly difficult. The preparations include knees, also laminated, bridging the side deck carlins with the big deck beam. Once these are in and sanded fair and smooth we can build up the layers of the coaming right on the boat using the deck framing as a bending form. I did each corner individually, with 3' long pieces butted on the centerline of the boat and scarphed into the long straight run of the sidedeck portion of the coaming. It is a tight curve. Using quarter sawn douglas fir the laminations had to be 1/8" thick and soaked in hot water before conforming. I clamped the three layers on the boat, still wet and steaming, for a couple of days before glueing them in place, one by one. Then I cleaned them up, cut the scarphs with a chisel, did mating scarphs on the long side pieces and glued those on. Finally I faired the whole assembly with about 1 1/8" extending above the decks, and laid down a neat fillet along the coaming/deck joint. One 12' two by four did the entire job. Barely.

The work described in this installment consumed hundreds of hours. But by now the boat is close to done, with only hull glassing and the construction of spars as the major shop projects remaining. Add to this homemade sails and all the rigging, and we have yet another article coming.