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Building the Valdivia– Part 2
by Patrick Matthews © 2006
Robbe’s 1:20 kit of the Valdivia– a Swedish schooner of 1868 which still sails the Baltic– is a challenging but rewarding r/c project. In the first part of this series, we got acquainted with the kit, and assembled much of the ABS hull and it’s internals. This time we’ll build up the deck and the sail winches, and then look forward to the masts and rigging in the third installment.
One of the most striking details of this model is the deck planking. Robbe provides mahogany and teak planks and white plastic caulking strips to build a beautiful deck, but the task isn’t trivial. Depending on how you approach modeling, this is either a lot of work, or an enjoyable way to spend a couple weeks in your workshop.
Repeating a lesson-learned from last time: Before laying any planks, ensure that you’ve run some countersunk screws through the deck into the beams below. This will guarantee that the beams don’t pop off during the planking work. And before starting, this is a good time to consider whether you’re modeling Valdivia as a museum ship in the modern day, or perhaps Valdivia of a hundred years ago. For the latter, consider black caulking!
We start by marking layout lines on the ABS subdeck– centerline, margins, and lateral guides for locating butt joints. The second lesson learned concerns marking the outer margin lines. After placing the king plank down the center, the margin planks are attached, setting the width of the entire planked deck. Robbe has us use a gage to mark the margin lines, offsetting from the deck edges. If the rough-cut deck edges aren’t perfectly symmetrical, then the planking pattern will be distorted port to starboard. As I can attest, a fair bit of work is then required to maintain the appearance of symmetry. Better to mark these margins as directed, then check and correct them for symmetry before laying the first plank. Also, identify the planks carefully before starting– some of the planks differ in width by only 1 mm.
Once the king and margin planks are attached to the ABS deck with CA, a process must be followed to lay in successive planks and to mark and cut mating joggles into the margin and king planks. Note that it’s not correct to trim planks to a sharp tapered point when they meet the deck edge, but rather they should be slightly tapered and cut off blunt, to lay into the joggled (or nibbed) margin plank. A sharp micro-chisel is useful for cutting out the joggles. Robbe also provides adhesive paper to temporarily apply to the margin planks, as it’s easier to see pencil layout marks on paper than on mahogany. Another detail I didn’t consider until after the fact– the margin planks are provided as single strips the length of the vessel. These really should be broken into several lengths with scarfed and caulked joints.
The caulking is provided as thin strips of white plastic which are somewhat wider than the plank thickness. The caulking must be applied to the butt ends of planks as well as along their lengths. I found it easier to first glue small pieces of caulking onto the butt ends and trim their height and width prior to laying each plank. The longitudinal caulking is easiest to glue down to planks already on deck. I applied drops of medium CA along pieces no more than about eight inches in length before placing them in position, as longer strips are difficult to manage.
The planking continues with care being taken to stagger butt joints on the marked lateral lines. Best to alternate one row of planking to either side, which lets you be certain of maintaining a symmetrical pattern. I’ve seen some photos of Valdivia’s deck though, and she does not seem to be so perfectly planked in her current condition– possibly a few random lengths have been used, and repairs have likely been made over the years. Also note that it’s not logical to continue the staggered joint pattern into the smaller areas between hatches, as these shorter distances would be planked with single lengths… something else I didn’t think about until halfway through!
Care should be taken to ensure that each plank is truly down on the ABS along it’s whole length. Slight discrepancies can be secured by running thin CA under the plank, but more sanding will be required later to level the deck. I used medium CA while applying the planks, and thin CA when it was necessary to “wick” the glue under a plank. I also used accelerator frequently when the CA didn’t “kick” right away.
Once the planks are all down, and after the celebratory champagne has worn off, it’s time to trim down the projecting caulking and level the deck. Robbe recommends sanding the plastic caulking. But even with hand sanding, I was smelling hot plastic and it looked like I might be driving the dust into the porous teak. So I tried scraping– first with a razor blade, but I quickly graduated to an old plane blade. Hold the blade vertically just like a woodworker’s scraper, and the plastic will come off quickly. I was happy that I had already trimmed down the bits of caulking at the butt ends, as it was easier to scrape along the planks’ length without those little speed bumps. Once the caulking is all scraped down, the deck can be sanded to the final level. Again, better to work along the length to avoid scratches in the soft teak.
For authenticity, you should not varnish the deck. Bare weathered teak provides a near non-skid surface for seamen, and that’s how the real Valdivia displays her deck. Robbe recommends an application of wax, which makes for an attractive natural but unweathered look and provides some level of water resistance. I’m not sure that water resistance is really needed with teak, but I also wasn’t sure that I wanted to risk finding out how the bare wood would perform.
Before the deck can be attached to the hull, we need to build the two sail winch assemblies. These each require a special sail servo, a rather beefy unit capable of handling the large sheet loadings and which can make four or five full revolutions. You can order the recommended Robbe servo, but a locally sourced Hitec HS-785HB is equivalent.
The main winch consists of a servo modified to run an endless chain around two sprockets. The assembly is straightforward, but make sure to give the unit a test run. I found a problem with the idler sprocket, which seemed to have a pitch error relative to the ladder chain, causing the chain to jump teeth with lots of commotion. By slightly rounding the teeth of this sprocket, smooth operation was obtained.
The forward winch also goes together easily. There are several plastic sheet guide tubes to be installed; I substituted an aluminum tube for the forward position, as it seemed easier to bend into the required shape. Make sure to chamfer and smooth all tube ends to avoid wear on the sheets. Also read forward in the instructions to understand where each sheet is routed next, as you may need to bias the sheet guides a bit in the right direction.
The sheets themselves are also installed at this time. Looking at the complexity of the lines below deck, and the small hatches, I’m hoping that I never need to go inside to service the affair! Adjustment of the winch travel and sheet attachments is made now too, which requires one to have a radio in hand. “End Point Adjustment” is required on each winch channel. I’m using a new Spektrum DX6 2.4 GHz 6-channel set, which is legal for surface use and which has computer trims and EPA on all channels.
One of the non-scale features we have to accept in an r/c sailboat is sheets which wind about the deck and disappear through holes into the hull. The jib sheet is actually an endless loop emanating from a forward cabin and encircling the main cabin well aft of the main mast. Fortunately, the sheet’s beige color lets it almost disappear against the teak deck.
Attaching the Deck
Once all is set with the winches and sheets, it’s time to vacuum out the bilges one last time before permanently gluing the deck to the hull. A wide perimeter flange provides plenty of gluing surface, but the wrong glue is worse than none at all. Robbe recommends Stabilit Express for all the major ABS gluing jobs. But it’s expensive and hard to find in the US, and it has a working time of only 10 minutes. “Mix up a large batch and have a friend help you”, say the instructions, because you’ll need to work quickly. I opted for 30 minute epoxy instead. The flanges were sanded, the epoxy was applied, the deck and hull were aligned, and every spring clamp in my possession was put to use. The following day, I started to trim the excess flange material with a coping saw, and noticed an odd sound. Suspicious, I pried on the deck, and it separated cleanly from the hull easier than if I had used a zipper. OK, time for the big guns! Still looking for an alternative to S-E, I recalled that “PL Premium” polyurethane construction adhesive had served me well when attaching stabilizer fins to 2 liter pop bottles used as water rockets– that’s a story for another day, but the PTE plastic in pop bottles is even harder to bond to than ABS. PL Premium can be found in caulking tubes at Home Depot, and hardens to a slightly pliable but machinable consistency. I cleaned the flanges, applied a bead of PL, reassembled the deck, and have had no further problems. If you’d like to try any other adhesive, please experiment first on scrap material.
The deck’s final edge can now be marked and trimmed. I roughed it out with a coping saw and easily finished it off with a 10 inch mill smooth file.
Before building and attaching the bowsprit, we need the knightheads– two vertical posts that in real life are stoutly set into the frame of the ship to locate the inboard end of the bowsprit. These are part of the anchor winch assembly in the kit, so that is built up per the instructions. The real winch is all black-painted iron work, so you’ll want to cover up the shiny aluminum and brass kit parts. Also the brass anchor chain needs treatment– I used “Blacken-It” to chemically color the brass. A hint of brass color shows through, giving an appropriately rusty tinge to the chain.
When the winch assembly is set on deck, the knightheads don’t have the appearance of being set through the planking. It would be more work, but I would have liked to set the planks around the posts for a better appearance.
The bowsprit is built up from formed wood and aluminum tubing. There’s a knurled brass “nut” that needs to be pulled through a hole in the aluminum tube. Robbe tells us to do this by torquing in a screw through the wooden stem… you’ll have more luck doing this off the boat using a made-up spacer. The fiberglass jib boom is attached to the bowsprit using several brass rings which must be soldered together. For strength, it’s best to use silver solder here. I also substituted some inch-size brass tube to make some of these rings fit better on the tapered jib boom. A number of fittings are attached to the jib boom, and careful reading of the instructions is needed to get these right. The jib boom is attached to the bowsprit at a skewed angle– mounted to the port side at the base, and with the forward tip on-center.
Two vacuum formed ABS pieces comprise the bulwarks. After trimming their edges, you’ll need to cut out four freeing ports in each. Robbe suggests a method using a metal guide strip and semi-free handed routing using a drill bit. I photographed my best effort, and patched up the divots in the others with Stabilit Express.
Stanchions are cut from square Obechi wood stock. Each needs to be contoured to fit it’s location in the curved bulwark. Molded-in marks are provided for stanchion location; the stanchions should be placed just aft of their marks, as placing them on-center will mislocate a few that show through the freeing ports. After assembling all the stanchions and a few other details, the bulwark’s flanges are masked off and the inside faces are painted white– easier to do now than on the boat. When dry, the bulwarks are clamped to the deck using strips of wood through the freeing ports, and thin CA is wicked into the joint to effect a permanent bond. Finally, doubler pieces are affixed to the transom for reinforcement; puttying and shaping is needed around the edges. As with the keel extension, I used Milliput to fill these joints, as it adheres quite nicely to plastic.
Here are two details you might consider adding to the bulwarks: First, the planking on the inside of the original’s bulwarks is not worked smooth and the edges are very visible, but we only have smooth plastic on the model. Wouldn’t be hard to lay in four thin planks for better appearance. Second, most of the stanchions should have rods set through them at midpoint to act as cavils (permanent belaying points).
With the bulwarks in place, it’s time to start masking and painting the hull exterior. Since most of the hull is nearly flawless ABS, it’s only necessary to give it a light sanding. The joint at the keel extension needs attention though; several coats of primer-surfacer should allow the previously puttied joint to be worked smooth. Follow with a light colored primer, and then mark the waterline per the instructions.
The edge of the deck forms a rub rail at the base of the bulwarks; this and a band at the waterline are painted white, and then masked off before painting the red bottom and black uppers. Feeling that it wasn’t safe to invert the hull with the ballast inside, I laid the hull on the bench and painted one side at a time. This job was too big for my hobby airbrush, so I used spray cans. I like to use matt colors for their faster dry times; I’ll apply a dull clear coat over all anyway. When all is dry, a light wet sanding will remove any edges at the masking lines.
The channels are now assembled with their deadeyes to the sides of the hull. The brass-work should be toned down; again, I used chemical blacking.
Cap Rails and Cathead
We are provided with three boat-length square strips of spruce to build each cap rail atop the bulwarks, glue-lam style. While this builds up easily, it might be better to form solid strips of a clear-grained wood for this very visible component, with scarfs along the length, or perhaps use the laminated method with clear-grained wood that doesn’t show the joint lines so obviously. The spruce has a very evident grain which is completely out of scale and it presents a toy-like appearance. I didn’t have confidence in bending heavy planks to fit the bulwark, and I knew if they started to straighten after getting wet they could distort the flexible bulwarks, so I went with the kit’s laminated method.
The curved cathead is also laminated from strips of spruce, and again it would be more authentic to build this up like a rib with futtocks. A few filler pieces are then fitted around the bowsprit and atop the transom, and we’re ready for finishing the cap rails. I looked in vain for a stain that would reproduce the golden-honey toned wood of the original under layers of varnish, until I found a tip from Bob Crane of Texas on the Seaways’ Ship Modeling List (http://groups.yahoo.com/group/SeawaysShipmodelingList/ ). Bob suggested using amber tinted shellac to recreate the color. I tried this and was quite happy with the result; Thanks, Bob!
Six deck houses are built up with die-cut spruce and strip wood on top of vacuum-formed plastic shapes. Still not happy with the heavy grain of the spruce, I substituted bass wood in all of the houses, and continued using the amber shellac to recreate the warm patina of old varnished wood. Some of the faces of the plastic moldings serve as window glazing, and care is needed to avoid scratching them while sanding the wood.
The wheel mounted on the aft house has an outer rim molded on; this should be clipped off, as Valdivia’s wheel has the spoke handles projecting. It’s mounted with a slotted head brass screw through the hub; by counter-boring the hub with an appropriate drill bit, you can set the screw head into the hub for a better appearance.
Robbe recommends a list of their proprietary electronics parts– radio, battery, speed control, and a special switch harness. These can be assembled per the instructions, which have the ESC, receiver, and switch all mounted on tabs accessible under the main cabin. You can also choose to source your own electronics, as I did for the most part, and you’ll likely want a different mounting arrangement. I didn’t want to obstruct access around the main “hatch” into the hull by gluing the kit’s mounting tabs as directed, so I made loose-fitting trays to mount the ESC and switch at the main cabin, and the receiver under the next cabin forward.
One design feature should be kept– power the receiver directly from the battery through the power switch. Don’t use the speed control’s BEC (battery eliminator circuit), as this feature can usually supply only an amp or so. The two sail winches can draw a total of 2.8 amps when working hard, and this could either damage the ESC or cause a “brown out” to the receiver. And when using a receiver battery, it’s best to disconnect the red, or middle, wire in the ESC’s receiver lead, which will keep the BEC power from fighting with the receiver battery voltage.
I’m using an Mtroniks “Viper Marine 15” speed control. The Viper ESC’s are totally waterproof, and have external power switches on pigtail leads. When you do use BEC, this little switch will shut down the receiver and anything else connected to it, which means you may not need a big power switch on the battery mains. In my case, it only shuts down the ESC, but this gives me the option of disabling the motor power should I want to have a “fair” race with other schooners!
The main SPDT power switch is set up to allow connection of a battery charger to another pigtail lead when in the OFF position, so the battery needn’t be removed for this chore. Robbe recommends their five-A-cell (6v) 1400 mAh nicad receiver pack for powering the model, and this fits into a bracket set in the keel area. The boat could be easily modified to take a standard 7.2v NiMH pack, which can be found with 3300 mAh capacities. Heavier wiring than provided in the Robbe switch harness would be wise for anyone wishing to charge such a pack in situ at high current rates.
Some care is needed in routing the wires in order to avoid fouling the winches and sheets below deck. This is another place where it would be good to know ahead of time what your plans are, as it will be easier to rig appropriate wire guides in the hull before attaching the deck.
Another Note on Tools
I mentioned in Part One that standard modeling tools would be sufficient for this build, but I have to add that it’s been a great aid to have a drill press, belt/disk sander, and a jigsaw to speed the work.
With everything up to the bulwarks complete, it’s time to start on the masts, rigging, and sails, which we’ll look at in Part 3.