Construction - II


Progress Report - Apr. to Sept. 1999

Well, a phenomenal amount of progress has been made, so it's high time to give another progress report. Currently I have spent around 130 hours on construction. Quite respectable since it took me 5 years to get to 230 hours on Failure #1. The most obvious change from the previous page is that the boat has gone from 2 dimensions to 3. Now at least I have something to show any visitors. Curiosity even got the better of my neighbors who eventually asked, "What is that?!?"

My comment last time about saying goodbye to the garage space has come to fruition as you can tell from this picture. The strongback was built first, which holds each bulkhead in position. I used a rented Dumpy level (like a transit on a tripod) to locate each bulkhead precisely. I couldn't use the garage floor as a guide because like most garages, it is not level. The most difficult bulkhead to position was the transom because it is at a slight angle. After a thousand measurements and adjustments, I finally had it as close as I could. Each bulkhead is held to the strongback with temporary screws. Now, the strongback is supposed to be strong, right? Yes, well, regardless of how strong it is, at this stage each bulkhead wobbles a bit. I didn't worry too much about it because I had a plan to help anchor each with some of the stringers that would eventually be installed anyway.

A note here about measurement tolerances. My goal at the beginning was to build the boat within 1/16 of an inch to the designer's plans. Hah! Further experience has shown me the folly of this idea. I'll be extremely glad if I'm within 1/4 inch or even a half inch in some places. But I'm not worried that I'll have a crooked boat. The critical parts, like bulkhead alignment, I know to be really close.

The next step was to insert the completed centerboard trunk. A moment of heartstoppage was followed by elation when the whole thing slipped into place. Everything matched up, except for a slight twist in the aft part of the trunk that I knew to be correctable. That's the joy and reward of building something like this. Seeing the parts built separately fit together as if divined to be. With that, the serious gluing and screwing began.

This picture gives a scan of the bottom and all of the integral parts. The centerboard trunk anchors 4 bulkheads together solidly. A cockpit stringer, shown in the lower center of the photo anchored the aft bulkheads together. Then it was time for the chine and sheer logs.

The chine and sheer logs are made of Honduras mahogany scarfed together to make a single 20 ft. long board. What I learned about this wood is...it doesn't like to bend. Not only was it supposed to bend around the bulkheads, it also needed to twist somewhat from stern to bow to follow the natural (?) curve of hull sections. I could only think of one solution to this dilemna. The Spanish Windlass. If you are unfamiliar with this concept, become familiar pronto. It is one of the most useful boatbuilding tools I know. Over the span of a couple weeks, I forced the logs into position and then let the area's humidity and heat take care of the rest. When I sprung them free to start the gluing process, they had already assumed most of the shape and didn't need quite the coaxing to get them into their final resting place.

This brought me to my most serious headscratching moment--what to do with the stem. The stem was already cut (oversized) and planed into shape, but it needed to be on an angle like the transom. The strongback didn't extend far enough for me to attach it, so what to do, what to do. I finally screwed a board to the stem that would stand on the floor, and the rest was glued and screwed in the proper position to the sheer and chine logs. Easier said than done, but it eventually did as it was told and was straight on center at the end. I did lots of checks first, because once the glue and screws are in, that's all folks! Very shortly after the logs were glued in place, I quickly worked on installing the hull sides because they would help keep the logs in place as well. I had this recurring nightmare of the glue failing and the logs flying off the hull like a giant spring. It didn't happen.

Putting together the topsides of the hull I once again departed from the building recommendations. Instead of piecing together the panels on the boat, I glued the panels together with butt blocks first and then placed it on the hull all at once. I admit that it's unwieldy to handle a 19 foot long piece of plywood, but I survived. I was familiar with this technique on Failure #1 so I stuck with it.

Now a note about plywood that I alluded to earlier when I was talking about a slight warp in the centerboard trunk. I used Marine Grade Fir plywood for this project. After dealing with a number of different types of ply over the years, I have come to the conclusion that it is impossible to make a 4 X 8 sheet that is perfectly straight and flat. Even if you bring it home flat, a few weeks storage in your garage will invariably turn it into a potato chip. Well, maybe I exaggerate. Fortunately, most surfaces on a boat are not straight, so I've made a habit of seeing how a sheet behaves first and then cutting it where it will follow the shape of the boat.

A note about measuring, cutting, and running out of things. It's always best to glue on a piece too big, then trim it later to size. Glue on too big, trim to size. Glue on too big, trim to size. Well, you get the idea. It's pretty important. One small mistake and it's another trip to the lumber yard to plunk down $200 to try again. Or worse. As for running out of material, make sure you have enough of something before starting a job where you can't stop. I was glueing one of the topside panels when horror of horrors I ran out of collodial silica filler before I got to the end. Since I can't glue this without some form of filler and I couldn't stop part way through, my panic found me using fine sawdust as a substitute. It has similar properties as silica so I wasn't too embarrassed in the end. But lesson learned.

Here is a view of the inside of the boat looking aft from the forward end of the bunk. This gives a better picture of how the bulkheads are attached to the strongback. Although it's a bit disorienting, you will recognize the shape of the bulkheads from the previous page. The center stringer helped secure the forwardmost bulkhead (A) to bulkhead C so it wouldn't wobble while I was installing the chine logs. This stringer will also be part of a longitudinal bulkhead under the bunk that I mentioned on the previous page under construction deviations.

Another view of the space between bulkheads A and C (B is just visible at the bottom of the photo). On the left is one of the 2 butt blocks on each topsides to glue the 3 panels together. The stringer glued on later will hold the bunk. Clearly visible are the chine log on top (of photo), and the sheer log on the bottom. I botched the bracing on the strongback for bulkhead A, not thinking about how the topsides and sheer log would attach. So I had to redo the bracing without moving the positioning. Must have had a special brain aneurysm that day. But my mess to fix it is barely visible here so I'm okay!

This shows the aft section. The transom is on the left, bulkhead G on the right. A longitudinal bulkhead will be attached to the center stringers, dividing the part under the cockpit into 2 compartments. This part will be done after the boat is turned over and before the cockpit is assembled. More visible here is a white epoxy fillet along the connection of the topsides to the bulkhead. Plywood is extremely sensitive to water entering the end-grain so I've religiously sealed every joint. These fillets are perfect for that little bit of left-over epoxy that you don't want to go to waste. All the other surfaces will be coated with epoxy later to further prevent water penetration.

Here's a nice picture of the bow, neatly nestled between my washer and dryer. The brown bag in the corner with the 7 inches of sawdust on top is my golf clubs. The plans call for a 5-1/2 inch radius curve from the stem to the hull bottom. I cut the radius in a scrap piece of plywood to use as a template and then let the belt sander take its toll.

A brief comment here about the stem. I used the plans to figure the angles and shape the stem. It's a bit weird since it has to taper from a wider angle at the sheer to a much narrower angle at the bottom. The moment of truth came when I installed the logs. The top was perfect, but the bottom was not. In reality the angle of the logs was a bit more acute. Some sweating and epoxy filler saved the day, but my advise to future builders is to find what the angles are in reality before cutting the stem. The ol' saying "Your mileage may vary" applies here.

The plans show the 1/2 inch ply bottom extending over this knuckle and up the stem to deck level. Ever try to bend 1/2 inch ply over a 5-1/2 inch radius? Well, even 1/4 inch ply breaks. Taking a clue from Failure #1, I soaked 2 pieces of 1/4 inch ply in hot water and carefully bent them over the radius. The 3-layer ply indicated lots of stress but it didn't fail. After it dried out I glued and screwed them in place, using copious amounts of silica filler. Fir plywood is fairly soft, but when heavily coated with epoxy/silica and then fiberglassed it'll be impervious enough to do a bow proud. Not that I plan on testing it or anything. Sailing will be test enough, I suppose.

Here's a closer look at the port side of the transom. The top shows the chine log and topside plywood has been planed down to match the angle of the hull bottom (basically level with the floor). The other side shows how the ply has still been left oversized. It will remain too long until the deck is ready to be installed. The ply also extended beyond the transom by about 2 inches, but has been sanded down flush in this picture.

Finally, a picture of the sheer looking from the transom forward. If you step away from the monitor a few feet and squint your eyes just right, you can tell what the sheer and cabin/coaming looks like. Actually this might be better in describing the amount of space I have to negotiate when doing things inside and around the hull. My son doesn't have a problem getting around, but he's a bit smaller than I (his tow truck stands ready in the foreground).

More detail on the strongback construction is shown here as well.

At press time the bottom sheet of 1/2 inch plywood has been cut to shape and glued together with butt-blocks. The lead pigs, made by a local castings place, now sit near the bow.

A word here about my evolution on ballast. I have devised a plan to secure the pigs by surrounding them with blocks of wood so they won't move and then lash them in place with lines attached to the blocks. The lashings would keep them from coming adrift during a knockdown or (heaven forbid) a capsize. The lashings will also allow removal during maintenance or a dire emergency. It will be easy to manage the ballast depending on loading, wind conditions, trim, and other circumstances. I won't shift anything once underway, but it allows some flexibility in how the boat can be set up. The designer requires a minimum of 600 lbs. of ballast with notice that the builder could increase it up to 800 lbs. So I purchased 700 lbs. as a reasonable start.

So at the moment I am gluing some 40 blocks to the bottom ply before I attached it to the hull. There are two reasons for this. First, I want to screw everything in place on the entire hull before coating it with fiberglass. That way I won't have to put a screw through the coating later, creating a possible source of moisture ingress. Second, gluing and screwing these blocks upside-down after the bottom is installed would be nigh impossible.

Then the next step will be attaching the bottom and fiberglassing the hull. That will entertain me for the next couple of months. Fiberglassing is something I never did with the other projects, so it will be a new experience. Rest assured that I'll be doing lots of reading up on it before I break out the cloth. After that I'll be doing the "turn-over" ceremony. Hoo-boy!


Previous Next