Blackrock 24 (Build)

Discussion in 'Wooden Boat Building and Restoration' started by LP, Mar 12, 2013.

  1. LP
    Joined: Jul 2005
    Posts: 1,418
    Likes: 58, Points: 58, Legacy Rep: 584
    Location: 26 36.9 N, 82 07.3 W

    LP Flying Boatman

    Framed

    I'm so gooed out, but the frames are all located and tabbed in place. As each frame was located, I added legs to each to set it's height vertically and to limit twisting around the longitudinal axis. The interior structure is setting frame spacing for the most part. The sheer clamp will be the ultimate lock down for spacing at the sheer. With the addition of legs to each frame, I was able to pull the saw horses from under the forward sections to get better access to the forward frames. It's nice to have the unobstructed access there. I will be able to cut the V-berth panels and use them to help index the outboard edges of the forward frames.

    IMG_2834.JPG IMG_2833.JPG

    I believe that I can start working the sheer clamp again and get it permanently installed. My short list of things to do right now is the sheer clamps, some edge doubles for the bunks and seat backs, breast hook, transom to sheer clamp knees and the second bottom layer. Some parts are made and some are not.

    A quick shot of my stabilization of the stem. I really only needed to set the stem on centerline. It set itself vertically and longitudinally. All I had to do was lock it laterally. Two cleats on a board with heavy stuff on it works great. I set marks on the floor as references to ensure it doesn't shift.

    IMG_2835.JPG
     
  2. LP
    Joined: Jul 2005
    Posts: 1,418
    Likes: 58, Points: 58, Legacy Rep: 584
    Location: 26 36.9 N, 82 07.3 W

    LP Flying Boatman

    The short list is getting shorter.

    Today I was letting the sheer clamps into the frames and doing my best to get a fair sheer. Not an easy task considering the restricted viewing angles offer by it's current position, None the less, I've been able to avoid some obvious funkiness in sheer by raising or lowering the clamp in places. Note to self: in the future, avoid putting fixturing where boat parts go. In this case, the support legs should have been positioned further inboard to avoid interference with the sheer clamps. I think I've got it dialed in to where it's going to live.

    I've started working on the transom knees and will progress to the breasthook/mast partner. I'll have to do the stem chamfers to get the clamps attached and to define the breasthook shape. Once all of these details are sorted out, I can mount them permanently and finish it all off with the second bottom layer. That will be an exciting day as it will define the start of the planking process.

    I took a piece of plank today and wrapped it around the stem and the forward four frames. Held at the stem and the forth frames only, it laid fair across all intermediate frames. I'll keep my fingers crossed that the same will happen for the rest of the hull. I spent a lot of time trying to utilize Freeships fairing tools to their highest potential. We'll see shortly how it turns out.
     
  3. LP
    Joined: Jul 2005
    Posts: 1,418
    Likes: 58, Points: 58, Legacy Rep: 584
    Location: 26 36.9 N, 82 07.3 W

    LP Flying Boatman

    A few shots of stuff.

    Some shaping of the stem. Before and after of the curve of the stem at the mast step. The power planer is a wonderful device that I have a lot of respect for.

    IMG_2845.JPG IMG_2857.JPG

    The breasthook blank. This will play a dual role as breasthook and mast pardners. Before being installed, I'll cut an undersized hole for the mast that will be enlarged at when the mast is fitted out. I've also got the transom knees cut and fitted.

    IMG_2859.JPG

    A shot of the tabbing between the stem and the forward bulkhead. I was surprised at how well the biax laid in here.

    IMG_2849.JPG

    Shots of the sheer looking forward and aft. I purchased some uni-cloth that I will cut into tapes for tabbing the sheerclamp to the frames. All I need now is some time to do the goo.

    IMG_2856.JPG IMG_2855.JPG
     
  4. PAR
    Joined: Nov 2003
    Posts: 19,126
    Likes: 498, Points: 93, Legacy Rep: 3967
    Location: Eustis, FL

    PAR Yacht Designer/Builder

    Doesn't it suck, when you go to all the trouble of radiusing the ventilation and lightening holes, just to have biax fibers hanging out and messing things up. It always pisses me off . . .
     
  5. LP
    Joined: Jul 2005
    Posts: 1,418
    Likes: 58, Points: 58, Legacy Rep: 584
    Location: 26 36.9 N, 82 07.3 W

    LP Flying Boatman

    LOL! You got that right, Paul.

    =================================================

    Figured out a way to get some transverse curvature into the transom. I have a few days to ponder this before I tie in transom knees. The current state of construction has the transom attached near centerline, but free at it's outboard edges. I am able to run bar clamps from the transom edge, forward a couple of frames to where the sheer clamp ties to the frames. This is a solid and fixed location so I can use the clamp to draw the outboard edges of the transom forward to add a small amount of curvature to the transom. :cool: I think that this adds esthetics to the shape of the boat for little additional work.

    =================================================
     
  6. LP
    Joined: Jul 2005
    Posts: 1,418
    Likes: 58, Points: 58, Legacy Rep: 584
    Location: 26 36.9 N, 82 07.3 W

    LP Flying Boatman

    Progress continues.

    The breasthook/partners are shaped and installed. An additional application of biax has been placed at the aft edge joining to the frame. Not pictured, but completed.

    IMG_2871.JPG

    The stern knees are in place. I think I need a second layer of wider biax at the transom leg. I plan to place a second offset layer on the side leg that will extend onto the hull planking once the hull is planked. At the time, I just grabbed some tape and put it on without thinking about the joint properly. Once the boat is flipped, I plan to sandwich additional biax between the deck and the knee.

    IMG_2873.JPG

    Tapping the sheerclamp to the frames. I used three layers of 8.75 oz. uni cloth. Only vertical tabbing was done as the fixturing interferes with much of the other tabbing. The remainder will be easier to apply once the boat is flipped.

    IMG_2872.JPG

    One final alignment check. The plumb line extends down from centerline on the "boxbeam". The lower line extends from the stern centerline to the stem centerline. When the "bob" lies directly over the centerline, or I should say, when the centerline lies under the plumb bob, the stemhead is on center. With the sheerclamps and breasthook all tied in, these lines should all be in agreement. If not, too @#$% bad. Nothing is going to be moving without some serious force or some serious disassembly. Fortunately, alignment checked out nicely, all is well and the lines are have been removed.

    IMG_2874.JPG

    Not picture is the second bottom layer of plywood that has been added. It's glued up and cured up. All that is left is to fill the matrix of screw holes left by the temporary fasteners used to clamp the layers together.

    And that my friends is then end of this chapter of the build. This little ship is ready to start receiving her hull planking! It's been almost a whole year since my first post, but if we skip all of the accessory building and jump ahead to where I start laying out frames (7/26/13), it's been seven months to get to this point. That time will have to be thrown back into the pot when the boat is done, but for this instance, I'm leaving it out.
     
  7. LP
    Joined: Jul 2005
    Posts: 1,418
    Likes: 58, Points: 58, Legacy Rep: 584
    Location: 26 36.9 N, 82 07.3 W

    LP Flying Boatman

    Finally got back to the boat. I have installed the first partial sheer strake. I always forget that the planking doesn't really start until you get past the sheer clamp. In previous builds, I've laid standard plank in lots of goo until I get past the clamp. This time, I opted to lay a single wider plank to get past the clamp in a single pass. I purchased some 1x4 mahogany and milled it down the plank thickness to act as my sheer strake. The forward sections laid in pretty easily, but the after sections took a little more coercion. If fact I originally thought I was going to have to lay it in two widths.

    Starting at the transom, there is a lot going on to get the plank situated properly. It has to be indexed vertically to the hull and then it has to be clamped to the hull without clamps, nails or screws. Also there is some twist that has to be dealt with due to the tumblehome. Central to this picture is a 1/2" x 1/2" x about 4" block that is screwed directly to the transom edge. This is the index for locating the plank. To the left of this block is a longer bit of wood that I call a cantilever clamp. It is shimmed out at it's upper end, cantilevers against a screw(head) that is also driven into the transom edge to provide pressure on the plank at the sheer edge to clamp and drive the twist into the plank. Whew! Fortunately the rest is simpler.

    IMG_2883.JPG

    Moving forward, you can see all of my clamping that was needed to seat the plank to the sheer clamp. Note the index on the frame forward of the transom. In this location, the index was meant only as a limit and the plank wanted to ride a touch lower and that was fine with me. Forward of the next frame, you can see a support (in front of the ball) that is limiting the downward location of the plank. This is the pivot point that I flexed the plank around to get it to lay into the sheer clamp. At the forward end of the plank, I had to flex it down at least one plank width.

    IMG_2885.JPG

    Looking forward, you can see that I used mostly spring type clamps. These were just a touch on the weak side so I had to supplement them with screw clamps to give that little bit of extra clamping force needed to get the plank to fay up to the sheer clamp. You can also see the supports needed to provide the upward force to make the plank match the sheer. The forward one of these was driven in after bending the plank in. Just that little bit more mechanical advantage to put things where they needed to go.

    IMG_2884.JPG

    And finally, the forward end of this half plank. These index blocks came in real handy when flexing the plank into place. I had them screwed to the frames first so when the plank was bent down, it would slip under the block and stay until I could get some clamps in place. Notice that the plank ends just past a frame and that there is a 30 deg overhanging cut on the end of the plank. There is a lot of pressure in the plank and having a frame so close to the end is beneficial since the full width of the plank will be constrained by the glue joint near it's end. If the plank had landed short of the frame, I would have been afraid the forces in the plank might cause it to split. Additionally, indexing the plank would have been difficult. The overhanging cut on the plank end will capture the next segment of the sheer strake so that the natural forces in the plank will force it into the joint.

    IMG_2882.JPG

    Whew! all of that for one half of a plank. Once the sheer strake is set, then there is no more indexing and just a continuous laying of planks until the hull closes up. This plank was done about a week ago and it been sitting clamped waiting for me to get back to it. I took the pictures before releasing the clamps. I was very pleased to see it stay in place with the clamps removed. Today, I installed the opposite plank and the forward half of this plank. Very exciting to have a whole plank installed.

    For most of the fillets in the build so far I've been mixing a blend of about 3 parts wood flour, 2 parts colloidal silica and maybe half a part glass spheres. The glass spheres lighten the color of the wood flour and I've found they are a little like ball bearings in your goo mix. Part of my design is that some joints are assembled dry and are somewhat open in nature. This let's me wet them out with straight epoxy and then work a thicken mixture into the joint. The glass bubbles, I think, improve the flow into the joints, but I've thrown some CS into the mix to put some strength back in. When I started working with the breast hook and transom knees, I changed to a mix that is probably 10 parts colloidal silica and maybe 1 part wood flour. I felt that these were high stress areas and wanted a strong mix. I had forgotten what a nice slump free paste CS makes. I am also liking the color of the paste with maybe 5% wood flour. It kind of reminds me of bearing grease. The CS makes kind of a translucent paste and with the wood flour, I think that the color is much more agreeable than a mix that is predominately wood flour.
     
  8. LP
    Joined: Jul 2005
    Posts: 1,418
    Likes: 58, Points: 58, Legacy Rep: 584
    Location: 26 36.9 N, 82 07.3 W

    LP Flying Boatman

    I had meant to talk about this in my previous post so here it is now.

    When I attached my first sheer strake plank, I went through a process to insure that I did not end up with a dry joint. The inside plank surface (sheer strake) was wet out with straight epoxy first as the mahogany (sapele, lauan or something similar most likely) is lighter with an open grain. This would give it a chance to soak in and I could check for dry areas and apply more epoxy if needed. The sheer clamp (douglas fir) was coated liberally next and with it's tighter grain, a second coating wasn't needed. In fact. the point of this post was to relate an experience (minor problem) I was with having too much epoxy on the clamp. I had anticipated more epoxy soaking into the DF and when it came time to apply the epoxy mixture thickened with CS, the thickened mixture was sliding off of the clamp in areas where there was an excess of epoxy from the precoat. It didn't happen immediately, but waited until the sheer strake was in position and about to be clamped. Then I would get these glops of thickened epoxy falling resoundingly on the floor. It's always something. :rolleyes:

    Anyways, I was very careful with the other planks to ensure that the sheer clamp was not overly wet before applying the thickened mixture. This way the only glopping that took place was from the thick mix being squeezed out as the plank was being snugged into position. Had the surface not been vertical this would not have been an issue.

    I have experience this in another way on the build with the dry assemble method I've used in places. I wet out my dry, open joints with straight epoxy to penetrate the joint and then go back with the thick mix to make the fillets. I've notice a tendency for the thick mix to slump a bit because it is applied over a wet substrate. Fortunately, at least in this case, it wouldn't slump all of the way off of the boat and the glass tape applied over the joint stabilized the whole thing very nicely.
     
    Last edited: Mar 9, 2014
  9. PAR
    Joined: Nov 2003
    Posts: 19,126
    Likes: 498, Points: 93, Legacy Rep: 3967
    Location: Eustis, FL

    PAR Yacht Designer/Builder

    This happens if you don't wait long enough. Next time, give the wetout coat enough time to gel and you'll have much less issue with a slippery wetout coat. I usually let a tight joint like this kick off, so it has some tack, but is well into the gel stage too. When bending stock around something, you'll have higher pressures in the most severe areas of the bends, which can compress the goo out of the joint, especially if over a slimy wetout. This can, as you know starve the joint. To prevent this I'll use fishing line (monofiliment). I wait until the wetout is really tacky, but nearing gel, then I press the fishing line into the wetout. When the thickened goo goes in and the assembly closed up, the fishing line acts as a spacer, prevent the joint from starving. Cotton string (kite string) works too, but usually is much thicker.
     
  10. LP
    Joined: Jul 2005
    Posts: 1,418
    Likes: 58, Points: 58, Legacy Rep: 584
    Location: 26 36.9 N, 82 07.3 W

    LP Flying Boatman

    I'm afraid that I don't always have the ability to let things go tacky here in the Great White North. :( On a busy day when Mix MaGoo comes to town, I might turn the thermostat all of the way to 62 deg while I'm working and them it kicks back down to 40 in the evening. I haven't used a fast hardner in a while and I like having the extra time slow hardener gives me to get things locked in. The last piece of sheer strake that I put on, I did late in the evening. It was still tacky in the morning and I might have been able to pull the clamps by that evening, but I left them in place just to make sure nothing was going to sproing on me. :eek:

    I did encounter something interesting with this last piece of sheer strake. The sheer clamp has been in position for several weeks. During the time prior to glue up, with in mechanically retained, I had a spray bottle with water in it handy that I would wet down the forward sections of the bent in sheer clamp over a period of a couple of weeks. It was in place so it was definitely going to accept the bend, but I felt I could relieve the some of the stresses by wetting it out as much as possible. Most likely, this did nothing for the internal stresses, but what did happen was the summer soft growth took the water and swelled substantially above the hard winter rings. This left a ridged texture that ran the length of the forward bow curve on the sheer clamp. Completely unintentional, but a convenient, natural home for my epoxy mixture to reside in while it cured. :cool:

    The wood was dry for a few weeks before I put any epoxy on it. I've used your fishing line technique in a few places in the build now.
     
  11. PAR
    Joined: Nov 2003
    Posts: 19,126
    Likes: 498, Points: 93, Legacy Rep: 3967
    Location: Eustis, FL

    PAR Yacht Designer/Builder

    The wet it out trick you tried does work, but it needs to be on the inside of the curve, not outside.

    Can you buy portable heaters? I have several I got from Wal-Mart for 20 bucks each and I can place them under something, drape a tarp over it and get a good temperature rise.

    [​IMG]

    This is the kind I use. Oil filled and two of them have had their safety features removed, so they can get really hot.
     
  12. LP
    Joined: Jul 2005
    Posts: 1,418
    Likes: 58, Points: 58, Legacy Rep: 584
    Location: 26 36.9 N, 82 07.3 W

    LP Flying Boatman

    Let the planking begin.

    Ummm... Paul, I don't think my wife will let me keep building boats.......If I burn down the house. :p


    It took me several planks to get my system down, but I've started making some headway on the planks. I'm doing a dry lay with gap between planks to be filled after the planks are installed. At least that is the plan. I did a test run on the bench that worked well and when I get about a foot wide section of plank done, I'll start the back-fill to see if I will continue with the rest of the hull in the same manner. If it goes well, I'll plank one foot wide sections and work up the hull. I feel like there will be a balance between too wide of a section that will be flimsy to work with and a too narrow section that will mean more, but smaller, bogging sessions. I am gluing the plank ends at the stem and the transom as I have not allowed for back-filling those locations.

    Each plank starts with a miter at the stem. I'm trying to have the planks miter up to each other at the stem. A quicker method would be to use a false stem to cover cut plank ends, but this time, I'm going to try to get a decent miter joint at the stem.

    The mitering starts with an extension of the plank line. The shaped stem is not trimmed flat so I'm letting the plank gap away on the forward side. I think this is the natural tendency so I'll plan for it and let the thickened epoxy do the rest. This line also tells me where the planks will want to meet at the back side of the planks.

    IMG_2899.JPG

    Next I draw the centerline as it comes off of the stem and intersects the plank extension line on the back side of the plank. I am also sighting down at the center location where the sheer strakes come together.

    IMG_2901.JPG

    Lastly, I draw the stem profile line on the back of the plank. This also intersects the plank extension line and the centerline. Then I cut it, set aside and line out the opposite plank.

    IMG_2902.JPG

    As part of the mitering operation, I also drill two dowel holes with a jig that
    I have made for this task, glue and insert a couple of bamboo dowels.

    IMG_2904.JPG

    The bamboo dowels are actually barbeque skewers that I cut to 2" lengths. I glue the dowels, but their true purpose is to align the planks where they butt together.

    IMG_2903.JPG

    A butt joint ready for action. The mating plank is drilled with the same jig and is pre-loaded with glue when it is slid into place over the dowels of the first plank.

    IMG_2906.JPG

    Once the planks are mitered and doweled, they are repositioned and nailed in place with spacers to set the gap. The forward foot or so is left un-nailed until the following section(s) of plank are nailed. The aft foot or so is left un-nailed also. At this point, I mix some straight epoxy to wet out the faying surfaces at the stem and transom. Once wetted, I thicken the remaining epoxy, apply it to the joints and finish fastening it all down. Any remaining epoxy is put into stem or transom fillets so none goes to waste. Then the whole process stars all over again. I don't know if I'll being saving any time, but the goo factor has been minimal since I'm not handling planks wet with goo. The goo sessions for filling the planks will be the determining factor and we'll be getting there soon enough.
     
  13. LP
    Joined: Jul 2005
    Posts: 1,418
    Likes: 58, Points: 58, Legacy Rep: 584
    Location: 26 36.9 N, 82 07.3 W

    LP Flying Boatman

    A couple of images of the planking. Both sides are planked equally.

    IMG_2908.JPG IMG_2907.JPG
     
  14. LP
    Joined: Jul 2005
    Posts: 1,418
    Likes: 58, Points: 58, Legacy Rep: 584
    Location: 26 36.9 N, 82 07.3 W

    LP Flying Boatman

    Here is the second part of the story. I'm coining the term "back-filling" though bogging might be a more common term. Bogging doesn't strike be as being structural where I believe that my back-filling is indeed a structural component. My mix is 1-2 parts wood flour, 1-ish part colloidal silica and a 1/2-ish of glass bubbles. My thinking is that the glass bubbles will soften the cured filler a bit so that seams will sand easier and not be so inclined to stand proud above the planks. The viscosity of the mix is about that of a thick syrup. It's remind me of pumpkin pie filling and is definitely a pourable mixture. The loose nature of the mix also means that it is epoxy rich so that there will be plenty of epoxy to be drawn in the open pores of the cedar planking.

    I finally settled on a Bondo blade/scrapper with a handle as my tool of choice. I put a convex curve in the blade and would lay this in my plate of pumpkin pie filling, spread a substantial layer of mix on the exterior of the planks and work the convex over the surface going across the gaps in the planks. The thin mix would work in fairly rapidly and if I was working too hard, it meant I need more mix on the hull.

    In the picture, you can see how the mix has been worked through the hull planking. You can see the mix is quite thin and readily runs down the hull. Also, you can how I have nails placed in between the planks to maintain a gap for the epoxy mix.

    IMG_2916.JPG

    This photo shows what the planks look like after being fully filled and the excess mixture removed. For as thin as the mix was, there was very little tendency for the mix to run out of the gaps. This will no doubt change as the planks progress around the turn of the bilge. I had just a bit of sagging where the over lying plank, over hung the lower plank. As I progressed down the hull (aft), I would periodically go back and help the sag back up to the seam. The sags were minor and by the time I got to the transom, the forwards seams were setting up and being good little children. The after sections were better aligned with each other and no sagging was experienced.

    IMG_2917.JPG

    Here is a sample of a frame to hull joint. I made the fillets under sized to lock in the planks so that when the hull is complete, I can resand the area, lay down a proper sized fillet along the whole joint and dress it out with a strip of biax tape. If you will look at the top edge of the plank at the frame, you'll see a shim sticking out. It's amazing that an 1/8" would matter when it comes to laying down a fair hull, but apparently it does. In a preliminary check of the hull with a sample plank, I saw that there was going to be a problem here so I was ready to contend with it. I'm not sure if the frame was too small or if the one behind it was too big. Pushing the plank away from the hull gave me a fair lay and that's what is important.

    (Edit: I was studying the photo and saw a contrast in the two different fillets that are seen here. The fillet from frame to sheer clamp and the fillet from frame to planking. At the sheerclamp that fillet was made strictly with wood flour and is very dark. At the planks, the mix is mostly CS with a small amount of wood flour to give it the color that you see. I find the lighter color more appealing, blending with the wood tones better and it will certainly be stronger with the high CS content.)

    IMG_2918.JPG

    The $200 dollar question is does this method offer any saving in time or mess? I think that this is not necessarily going to be a speedy process. I believe that I am doing just as well and most likely better than on my 16 footer where I glued as I went. My first back-filling mixtures were thicker and took more time. Each progressive batch got thinner and thinner until I reached the thick syrup viscosity. I did not put a handle on the Bono blade until after doing one whole side and a third of the second. This sped things up a bit and also got me farther from the goo. Distance from goop is good. Things got considerable drier from this point too. I'm willing to go another round with this process to fine tune the technique a little more and to see if my speed will improve. The biggest draw back I see is the amount of epoxy mix required to fill the gaps. Maybe 4-5 times as much as a glued then nailed plank. More fillers would be nice, but the wet mix is needed to work it into the gaps relatively quickly and to insure that there is plenty epoxy available to the planks once they are filled.
     

  15. PAR
    Joined: Nov 2003
    Posts: 19,126
    Likes: 498, Points: 93, Legacy Rep: 3967
    Location: Eustis, FL

    PAR Yacht Designer/Builder

    Maybe taping the back side of the planks and using a syringe to squirt a thicker mixture into the gap, much like caulk. If you want to go to a bigger scale, a 10 ounce caulking cartridge and a pneumatic gun (saves you hands, trust me), could be a very fast, precise and accurate way of getting goo in the seams. A trick I use when I caulk or applu goo like this (pneumatic gun) is to angle the tip away from the direction of the push, so as it pumps in, you're forcing it into the gap with the pile of goo before the tip. I also try to shape the tip to help level the goo, as the tip moves over the seam, by cutting flat on the bottom, back edge of the tip. The result might be no leaking out the back of the seam, if you work carefully and shape the back of the tip flat(ish), you'll fully fill the seams and semi wipe off the excess too. Worth a shot anyway, with the many hundreds of feet of seams you have.
     
Forum posts represent the experience, opinion, and view of individual users. Boat Design Net does not necessarily endorse nor share the view of each individual post.
When making potentially dangerous or financial decisions, always employ and consult appropriate professionals. Your circumstances or experience may be different.