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| POB fun build...HMS Zephyr | ||
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Moderators: Winston, aew, bikepunk
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| Author | Post | ||
| Gene Bodnar |
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  Registered Member #126 Joined: Tue Jul 21 2009, 11:20amPosts: 1782 | Bob, Great start to a very promising building log. Love the photos, which couldn't be better. Gene | ||
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| BobK |
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  Registered Member #1657 Joined: Mon Jun 20 2011, 12:33amPosts: 16 | Thanks Gene! The digital camera is one of the greatest inventions of our lifetime, along with the internet of course...I take a ton of pictures when I build anything, and it's nice to be able to post a pic and get some feedback where needed, or just demonstrate how to do something online is just a lot of fun. I've got the bulkheads all stabilized to the point where I was able to remove the model from the jig, and get both garboard strakes fayed and epoxied firmly into place. My initial plan was to try and plank the hull in 1/16" plywood and top it with 1/16" hardwood. That plan has changed for a variety of reasons. First, plywood planking would be overkill and very difficult to apply. The curves are so extreme fore and aft that planking is nearly impossible. Instead I am forced to use balsa blocks in a couple of spots, and for the first planking I am using 1/8" balsa strips. I have a strip cutter and I can cut the exact widths I need to fit, they are easy to fay together and attach very firmly to the bulkheads, which are spaced on about 1 1/2" centers. It's also near impossible to find hardwood planking strips 1/16" thick, and I do not have the proper saw to make them myself. So the compromise will be .20" thick veneer strips epoxied over the sanded, primed and prepared hull, and then a thin fiberglass cloth vacuum formed over the whole thing. I have a vacuum pump and have done exactly this kind of fiberglass work on a hull before. I scratch built a harbor tugboat a few years ago (alas, pre-digital camera days...) and the fiberglassing worked out well. I use West Systems epoxy with a slow hardener. The lower hull along the keel is going to get reinforced inside with strips of fiberglass cloth and resin, so that I can install ballast in those spaces all along the keel. This hull is going to need an incredible amount of weight to get it down to a proper waterline, and I will be able to use some removable ballast, but where I can I intend to install permanent ballast in the hull in the form of #8 shotgun shot and epoxy resin. I'll weigh out how much I use and I have the hull's center of balance indicated on the prints, but putting a fair amount of shot down as low as possible in the hull is a very good thing. Another ballasting convention the British (and others) used was the "shot locker". Right next to the mainmast at least, was a tall thin locker where cannon shot where stored. Ready ammunition was kept on the shot garlands on the gun decks, but when those shot needed to be replenished, out came the rounds from the shot locker. Of course they where rusty, and chipping them made them smaller, increasing the "windage" around them, and compensated for by increasing the powder charge. But the shot lockers provided a great deal of ballast where it was needed most amidships, and right next to the mast where it could counteract the side forces generated by the sails. The shot locker's locations amidships might help ameliorate the "hogging" of a hull from all of the weight of the guns forward and aft. HMS Victory was found to be hogged almost 18" when she was drydocked for the last time...such is the cost of carrying 100 guns. I have allowed space fore and aft of all three masts for a "shot locker" that I can mold a removable ballast block. Once I figure out how much additional ballast she needs, by actually floating her and measuring waterlines, balance point, port and starboard level, I'll line those holds with lightly greased plastic sheet and pour in an appropriate amount of shot/epoxy. My tugboat needed four blocks that totaled almost 80 pounds, and without making the ballast removable it would have been nearly impossible to handle that tug hull. Same goes with this one. I'll be working on the bow this coming week. The Missus is home from the Republic of Tejas today so my real life responsibilities will be intruding on my available modeling time. Such is life. Everyone have a great week! | ||
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| BobK |
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| Registered Member #1657 Joined: Mon Jun 20 2011, 12:33amPosts: 16 | Its been a while since I updated this thread, and since I downloaded 96 pictures off my digital camera last night, I have quite a bit of material to share. I work on the model for a couple of hours at a time and I usually find time every day to do something. The first planking is well underway. Originally I thought this hull might need a lot of reinforcement in the form of light plywood covered with hardwood. But when I began assembling the frames to the keel it became very clear that there would be no lack of strength if I used balsa instead, so I have proceeded with 1/8" hard balsa planking, and will cover that with a second "show" planking of .20" hardwood veneer. On to some pictures...  I used thick CA to secure a top rail around the entire top of all the frames to keep them in place, and along with the plywood radio boxes in side, the hull was stable enough to remove from the building jig and invert. I started by carefully fitting and installing the garboard strakes on both sides with 15 minute epoxy. I used some 1/8" plywood strips to protect the balsa from the clamps, and made sure that the strakes fit tightly into the rabbet on the keel. I did the same for the second strake on both sides and epoxied it to the frames and the garboard strakes and clamped it until solid. Then I went back and painted the entire inside of both strakes and all of the frames with a coat of lightly thickened epoxy to make sure I had a fillet at each joint.       I found it difficult to find a way to stabilize the bow properly for planking because of the extreme curves and diminishing profiles of the frames. So I decided to fit the bowsprit mount. I used my Great Grandfather's auger bits and a hand brace to carefully drill the mounting hole for the brass mounting tube. I beveled the end of the tube so it would butt tightly against its support bulkhead and I mounted a collar on the bulkhead to hold it. You can see the tube lays down on the beak support right above the gammoning holes. My intention is to cut that tube down to a shorter length later so that the dowel rod for the first section of the bowsprit will mount in it later. The tube has a nice tight fit and I did not glue it into position just yet. It is convenient to be able to remove it later for sanding the hull.       After much internal deliberation I decided how I wanted to make the rudder. It will have a tiller up on the deck and needs to be a bit larger than what the original was. I sketched out a rough shape on a piece of 5/8" Western red Cedar (it's a cutting from the bottom of a fence board) and roughed it out on the bandsaw. I then chiseled a groove out of the leading edge, and CA'd a 1/4" dowel rod to it just at the top and bottom. That gave me a handle to use in order to shape it on the belt sander. I left it a bit wider than finish size for now and moved on to fitting it. I epoxied a 3/8" dowel rod to the rudder, and once it was hard, I fitted it up through the stern and cut it off about 1" longer than finish size, for now. I proceeded to mark the hull and rudder for the opening for the 1" propeller and cut them out. Because the dowel rod is in a plywood guide built into the hull, it needs no hinge up top. The rudder gets one hinge down low. I used large model airplane hinges that have a stainless steel pintle. I removed the pin and filed the retaining lugs down so it fits tightly but smoothly. I proceeded to fit the rudder half in place, and after trimming the nylon to fit, epoxied it firmly into place. I cut the groove in the rudder post for the other half of the rudder but will not mount it until later when sanding is complete. OBTW, that blue stuff is just a bit of automotive body filler (AKA "bondo"). Its inexpensive, easy to use, sands nicely and is compatible with fiberglass and most finishes. Since this hull is going to sea, we'll leave no potential leaks to chance, and I have been doing some rough shaping and filling as the hull progresses.  As you can see, the inside is looking pretty good. Once the planking is complete, I will painting the entire inside of the hull with slightly thickened West Systems marine epoxy. It will ensure a perfect bond as well as strengthen the balsa and waterproof it.  Just for fun last night, I put dowels in place where the masts and bowsprit will go just to see what we have so far. I need several more days to finish the first planking and get the hull profile defined before final planking. I am working on a sail plan now, and it will not be a conventional square rig like this ship was designed for. Again, the hull profile is the only thing that is close to "scale" on this build and the intention is to sail it under radio control. Square rigged ships were limited in how closely they could sail to windward, or into the wind, because of the limits that the rigging itself would allow the yardarms to be pivoted from side to side in order to meet the wind. Because of that, square riggers took a lot of time tacking and beating to windward because of the angle that had to be maintained with the wind. The most efficient sails are those mounted along the long axis of the ship. Jibs and staysails, with or without a boom, allow a vessel to steer more closely into the wind, and cuts down the distance the ship has to sail from side to side when beating into the wind. With that in mind, I intend to give this hull a modified "schooner rig", and when I have the design in a form I can post here I will....at this point it is only a concept and a few drawings, but I feel confident that the boat will look very attractive with the rig I have in mind and should sail like a champ. For now, its back to the planking for me. I am not steaming the planks before I install them, instead I am using a different technique that some may find useful.  I'm using 3/4" wide strips of 1/8" balsa for planking. Once I have one dry fitted, I find a place around the middle that fits perfectly across at least three frames. Using thick CA, I fasten it tightly at that point and let it cure. Then I take a clean wet rag, and wet the balsa plank along the whole length, and underneath as much as possible. Then I heat up my trusty monokote heating iron from my RC airplane days, and use the hot iron to steam the plank into shape where it is. It works just great and really helps form the balsa around the curves of the hull. If necessary I do it a couple of times until the plank is shaped to my satisfaction, then I CA it into place. Ironing the plank then helps set the CA completely and bonds the plank as well as you could want. That's where we are at the moment, and the planking continues. The lines of this hull are starting to emerge, and she will be quite a looker out on the water! They say there are two types of sailboat hills: Racers and Voyagers. This one is a voyager, and I hope to demonstrate who well she sails next Spring... Cheers! | ||
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| Gene Bodnar |
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| Registered Member #126 Joined: Tue Jul 21 2009, 11:20amPosts: 1782 | Bob, Great build. I love the photos and narrative. Gene | ||
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| BobK |
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| Registered Member #1657 Joined: Mon Jun 20 2011, 12:33amPosts: 16 | Whew! Finally getting the chance to pop back in here and do some catching up. Its always so unfortunate when real life interrupts our internet time..... Thanks Gene! I appreciate your kind words and encouragement. I just downloaded another 67 pictures off of my camera, 90% of which are model related, and I will be doing a big picture post this weekend. I have one side of the model almost planked, and there is a lot to tell about where I left off here, and where the project is this morning..... For starters, she has a new name and almost half of a new mahogany skin....  Developing.... [ Edited Sat Oct 08 2011, 02:17pm ] | ||
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| BobK |
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| Registered Member #1657 Joined: Mon Jun 20 2011, 12:33amPosts: 16 | How time flies when you are having fun! I'm not really delinquent in my attention to modeling, but have been off on a bit of a tangent of late while the hull remains partially planked. First though, I've decided on a new name for the model "Zephy"; after the Greek God of the Fair West wind that blows in the late Spring and early Summer....Zephyrus....With the sail plan I have in mind, this boat will fly on just a breath of air, so the name is appropriate. I intend to finish the mahogany planking by applying a thin layer of fine fiberglass over it via vacuum bagging and resin infusion. That requires a reliable vacuum pump, and that is what I have been working on the past week along with getting set up to actually glass the hull. Years ago I worked for a chemical plant who started out using all fiberglass piping for their process. Eventually they transitioned to stronger and more reliable materials like stainless steel and different plastics, but originally when they had to repair a pipe, they used polyester or styrene resin (depending on the pipe) with fiberglass batting and cloth to make up pipe joints, and they vacuum bagged them in the field to compress the glass and make sure the pipe joint was as dense as possible. To do that they used a Dayton Speedaire 1 HP rotary vane oil-less vacuum pump. We cleaned out our maintenance storeroom, and I came across that pump and motor set. It had no power cord and the glass collector bottles that it came with were missing. They had used it enough times that they had filled the suction jars with hardened resin, and since they were transitioning to better pipe, it went on the shelf and was forgotten. My boss told me I could have it if I wanted it, and it has been floating around my garage or shed for almost 15 years. This past week I disassembled the pump and motor, and cleaned both. It had sat so long that the lubricated bearings were very tight, but I gave them a shot of dry silicon lube and they freed right up. The graphite vanes were all stuck in their grooves and the whole inside of the pump was filthy. I cleaned it with some engine degreaser and dried everything carefully. The seals were all still intact and in great shape so back together it went. I mounted it on a plywood base, and made a vacuum chamber/resin catcher out of some 4" black PVC pipe and a couple of end caps. I have a practice kit coming this week that demonstrates several materials and techniques for resin infusion, and I'm going to do all of them before attempting to glass the hull. In theory, you attach your fiberglass cloth to the model with contact cement, and add the necessary layers of absorbant, release film and special plastic vacuum membrane that stretches 500%. Once you seal it down and make sure there are no leaks, you put the piece under vacuum, and then inject a measured amount of mixed epoxy resin and hardener, and it is drawn into the fiberglass cloth and compressed to optimum density. Once the epoxy sets you can peel off the bleeder and ply, and you have (in theory) a finished surface that is ready to go. In theory. Hence the preparations lately to make sure my equipment is up to par and that I know what I am doing when it comes time to glass the hull. I hope to have my vacuum rig completed this week and get back to planking again. I started to set up to plank this morning only to find that my trusty old Monokote heating iron has assumed room temperature for the last time. I finally burned it out warping planking into shape after ironing dozens of rolls of airplane monokote over the years. I feel like I should give it a decent burial, it's like losing an old friend.... Anyway, I am not slacking and have a zillion pictures to put up, but for now that will have to wait. Hopefully this week I will find some time and get this thread caught up... Cheers everyone! | ||
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| DanO |
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  Registered Member #115 Joined: Tue Jul 21 2009, 03:01amPosts: 92 | Bob, You have been doing a great job and I must say very inventive especially with your last post. I can actually picture in my mind as to what you are up to because your thought process and descriptions are so clear. Thanks for sharing Dan | ||
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