Blackrock 24 (Build)

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

  1. LP
    Joined: Jul 2005
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    Location: 26 36.9 N, 82 07.3 W

    LP Flying Boatman

    Board box preparations.

    SS, I might have been able to install the case log (hog?) and box components before planking. It might have made that portion of the build less stressful. I think I was leaving my options open with regard to the centerboard even though I knew I would be installing one. The opening of the slot is certainly done with trepidation. Your idea of leaving bridges is a sound one.

    --------------------------------------------------

    In preparing to install the box, all manner of little jobs had to be done. A final check of slot dimensions was done against the drawings and more importantly, against the board itself. As an after thought on the board, I had utilized the overhanging sheathing cloth (18 oz. weave) to hold some epoxy/CS mix to form a hardened trailing for the board. This added 1/2"-3/4" to the length of the board that had to be accounted for in the slot and possibly in the pin location. Also, I had allowed for a total of 1/4" slot clearance on the sides of the board. Split between the two sides, this was only 1/8" on either side. I always seem to build tolerances too tight and having a too narrow slot could be a serious headache. A "board" meeting was held and it was determined that slot clearance should be doubled to a 1/4" on either side. Reducing slot size, if necessary, would certainly be less of a problem than trying to open it up after the fact. As a side note: the board has been completed for over a year and has been set aside to wait for installation (and modifications. Argh!). A quick check on it's condition shows it to be holding true with no noticeable inclinations for warping. Yeah!

    The width of the slot was recut, the pivot location was modified, the aft end shape of the slot was finalized based on board dimensions and pivot location, and the shape of the forward end of the slot was recut based on the previous criteria.

    Cutting the forward end:
    The forward end of my board has a 13.5" radius so I wanted at least a half inch of clearance before glassing. The slot was opened forward until I had 14" from the pivot then I used this little bit of silliness to get a tangential opening to the pivot. I laid the framing square against the pivot location (screw) and put the corner at the cut edge. This gave me a sight line for drilling and multiple holes made with a paddle bit get me started. A sawz-all and a rasp finished up the procedure.

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    The forward post (not really a post):
    A clearance line was drawn with trammel points. Fillers were cut to fill forward of the line. The box is tapering in the area so calculations were done to get proper thickness and taper. I was trying to avoid having a feather edge. It was going to take two layers to fill the area and I planned to have the second layer a constant thickness. Each layer shaped and bedded. Grain orientations were also set against each other. Lastly, the interior corner was filleted and glassed while still exposed and easily accessible.

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  2. LP
    Joined: Jul 2005
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    Location: 26 36.9 N, 82 07.3 W

    LP Flying Boatman

    Other box preparation.

    So many little jobs that need to be done.

    In these photos, the inside surfaces of the box have been sheathed and the weave filled. Two additional layers of cloth (first photo) were added where the board is planned to bear while extended. The thickness increases as the board is more fully extended. At the pivot (second photo), a pad of 24 oz. triax was laid and covered with a layer of cloth as a bearing pad for that location. A matching pad was added to the other half of the box. If there is still clearance, I may add similar pads to the board itself. A layer of ply was also added outside of both sides of the box to carry vertical loads from the board.

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    Last edited: Sep 7, 2014
  3. LP
    Joined: Jul 2005
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    Location: 26 36.9 N, 82 07.3 W

    LP Flying Boatman

    A big day!

    The second half of the board goes in! Of all days where a helper would be useful, I was flying solo on this day. This installation was a major operation and a logistical challenge. The side of the box was in two pieces and had to be assembled in place as there was no way it would be going in as a single piece. The case log had to go in as a single piece due to it's structural nature. Assembling it in place wasn't an option. Independently, or even together, none of this was too difficult, but figuring out how to do with wet epoxy in all of the right places and keeping it in the right places AND squeezing in out before it gets hard IS the challenge.

    The whole process started with dropping the forward board section though the slot to have it handy, applying a peanut butter of epoxy and CS to the forward box post and the forward portions of the slot. The forward board section was lifted into place and a single screw was used to hold it loosely in place. It's aft edge was allowed to hang loose from the structure to give clearance for applying more epoxy mixture.

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    The forward board section was "primed" with straight epoxy where the case log would bear. The board was dropped in though the slot and to be ready for install. More "peanut butter" was applied to the board box where it would bear on the hull and case log. The case log was buttered where it it would bear on the hull. The forward and aft ends of the case log had been tapered/undercut so that the pre-buttered areas that it was pushed into would not be scraped clean during the process. It also gives the epoxy a place to live once the piece is in place. Also of note at this point: I was pumping small quantities of epoxy at this point and quickly realized this was going to be too time consuming. The nature of this installation was that almost no part of the assembly could be snugged into position until all components were properly epoxied, in position and ready the final snugging/tightening. This meant I had a real time constraint if I was going to be successful. The big mixing pot came out and a REAL batch of peanut butter was made and spread out on the components as quickly as possible to keep it from going thermal.

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    The buttered board is lifted almost to position. The aft board post is buttered. The aft case is buttered. The aft end of the case long is pried out to give clearance to for the epoxied case component.

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    After the fact. The goo factor got extreme that day. Things were getting very sticky by the time I was able to get everything properly in place and snugged into position. I cleaned as much excess off as possible and got the heck out of the kitchen, er...I mean galley. These are day after photos. In the first photo, you can see the seam of thickened epoxy at the joint between case sections. This was somewhat intentional. I had to remove material from the forward end of the forward case section during pre-fitting to get it to go into position and opted to plan for a gap between sections that would get filled during assembly rather that deal with keeping epoxy in a tight fitting joint. I debated some sort of scarf here, but chose to go with a butt block. The case log backs the joint in that location. The butt block is in a fairly non-visual area. The bridge deck gives additional support and there will only be a 3-4" length that is unsupported above deck. I will most likely apply a small area of bi or tri in the area and fair it at a later time during construction. During this part of construction, I backed the inside of the box with a packing tape lined piece of ply and the lower (upper) outside, unsupported portion with the same.

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    Parting shots. Exterior slot shot and a look at the inside of the case joint.

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    Yesterday I filled assembly screw holes that penetrated the case, did some additional epoxy clean-up, applied fillets and tape to the remaining inside corners of the box and sheathed the transom.

    I think that gets me up to date finally. What else is there to do when you wake up at 4:30 in the morning? Beside working on the boat.:D
     
    Last edited: Sep 7, 2014
  4. LP
    Joined: Jul 2005
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    Location: 26 36.9 N, 82 07.3 W

    LP Flying Boatman

    There you go. Typos in the last three posts have been fix. Sorry. Just trying to get everyone up to speed.

    I finally have a short list for boat roll over.

    1. Tape the slot opening.

    2. Cut opening for motor well.

    3. Sheath the central bottom portion of the hull.

    4. Install skeg and rudder structure.

    5. Final fair of the hull.

    6. Prime, paint and varnish hull.

    It's a short list, but still a large amount of work. I'll keep plugging away at it it will be done before spring. Hopefully, before years end, but I'll just not get too cocky about that.
     
  5. LP
    Joined: Jul 2005
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    Location: 26 36.9 N, 82 07.3 W

    LP Flying Boatman

    Shop shannanigans and other flotsom.

    I went to drain my air compressor tank and could not get the thing to seal up again. The stock drain was a pain to get to and operate anyways. The solution was in a trip to the Depot for plumbing supplies and build a whole new drain system. The result is shown below. Purging the tank is so easy now that I have no problem pulling the moisture out with each use. An unplanned benefit of the new system is that the tank has a small reservoir for condensation away from the steel tank. No more purging rusty water. I comes out nice and clean as the accumulations now reside in copper tubing rather than the steel tank.

    IMG_3335.JPG IMG_3336.JPG

    Old shop vac hoses never die. They just loose their suckers. :p A bit of duct tape and my shop vac has twice the range. I can use all of the help I can get in this arena. :D

    IMG_3337.JPG

    And finally, a shot from the galley....um, the kitchen. Occasionally, I HAVE to do something for the wife. The excuse that I'm no good with wood just doesn't seem to work with her. :confused: Oh well, I'm pretty free to undertake just about any boat building endeavor that I want and it's my wife's open mindedness that makes it possible in so many ways. :cool:

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  6. LP
    Joined: Jul 2005
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    Location: 26 36.9 N, 82 07.3 W

    LP Flying Boatman

    Cutting the O/B well orifice.

    One more hole to cut. This one will be much simpler to do over the centerboard slot. All structure is in place so it's simply a matter of cutting the opening and putting the finish on it. My homework at this point was a quick run down to a marine dealer to take some measurements from an outboard the same size as what I want to utilize. The final answer is an aperture 8" wide by 13" long. The motor I measure had a 7.5", 3-blad prop. I'm thinking I would prefer a 2-blader, but I made the hole 8" just in case.

    Photo #1: The layout initially drawn at 8x12 and redrawn before cutting. Note the calibrated cottage cheese container radius gauge. Nothing but the best tools for me. :D Photo #2: The aperture cut and radiused. In an effort to save the cut-out, I did plunge cuts on the hole sides with my circular saw and cut the remaining edges with my saber saw and a brand new blade. I shoud be able to use the cut-out as a door to restore some hydrodynamics around the motor leg. Photo #3: lining the hole with glass tape. Photo #4: Sheathing applied in the vicinity of the aperture. Between sheathing and tapes, there will be about four layer of glass protecting the O/B aperture. Motor legs are sharp and heavy so a fair amount of protection would seem to be the plan for the day.

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  7. LP
    Joined: Jul 2005
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    Location: 26 36.9 N, 82 07.3 W

    LP Flying Boatman

    Completing the bottom sheathing.

    Before sheathing, I needed to finishing securing the case log. This was to be a two fold procedure. First, I didn't was heavy filleting and taping in the cabin interior in the hopes of leaving the option of a bright finish available. For this reason I resorted to mechanical fastenings every foot for the length of the case. 4 1/2" x 5/16" SS lag bolts were used here. The counter bores were drilled first and then the pilots for the bolts were drilled to the proper depth. A very slightly thickened epoxy mixture with CS and milled fibers was poured into the counter bores and allowed to run down into the pilot holes. The bolts were then driver home. The first intentional permanent metal! Once this was done, the counter bores were with thickened epoxy and a 12" width tape of 24 oz triax was laid over the exterior corner of the inboard case side.

    Further preparations included cutting the cloth for the center section and using the cut offs as fillers between areas of triax. I wanted to do a single length for the final layer so a full length piece was rolled out. The center piece was rough cut and put away. This left a nice amount of remnants that could be placed strategically on the bottom to help fill low areas and provide additional protection on the bottom of the hull.

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    Here you can see the triax that wraps the CB case corner (upper left) and also a length of triax that wraps the "chine" on the tight in way of the saloon (upper right). I have a double layer of ply down the central portion of the hull that allows me to have no floor in way of the main cabin (saloon). I've added additional structure at the ends of the CB box to replace the removed sections in the cabin. I was feeling uncomfortable with the lateral connects in way of the saloon, so this extra bit of triax throws a little more peace of mind my way. Between the lengths of triax, I've placed a double layer of sheathing cloth to build that area up. Aft of there, I've placed a filler layer the fits between the outboard sheathing layers. Forward, I added a layer that overlaps the outboard sheathing layer that also overlap themselves. In the forward sections of the bow, there will be up to four layers of the sheathing cloth for abrasion protection should I decide to beach the bow on occasion. Next, the piece mealed fabrics are wetted out. The last two photos are after cure and cleanup. A thickened mixture of CS was used to fill the gaps and give some initial fairing prior to the final sheathing coat. I used CS prudently as I did not want to have to sand the filler material, but I also wanted a structural filler underneath the sheathing coat.

    IMG_3329.JPG IMG_3330.JPG IMG_3331.0.JPG IMG_3331.1.JPG

    The final, central sheathing is applied. I did not wait for the CS mixture to kick. I opted to apply the sheathing layer while it was still wet. This added a little bit of challenge as the cloth wasn't free to slide around. Otherwise, wet out was pretty straight forward. I believe that the strategic layering of the various cloths has reduced the amount of final faring that will need to take place.

    IMG_3331.2.JPG

    This and the outboard aperture takes three items off of the roll over short list. There is still a lot of work, but I can start working on attaching the appendages now that the sheathing is complete. I'll be fairing the hull and filleting and fairing the appendages all at the same time.

    Progress, progress! Woo! Woo!
     
  8. LP
    Joined: Jul 2005
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    Location: 26 36.9 N, 82 07.3 W

    LP Flying Boatman

    Mounting the skeg.

    IMG_3338.1.JPG IMG_3338.2.JPG IMG_3338.3.JPG IMG_3338.4.JPG

    Buttered up........................ Flipped and placed............... Filleted and taped................ Rudderpost too.


    Two layers of 17 oz. biax were used. The stuff is incredibly pliable. I wrapped the first layer completely around the leading edge of the skeg and trimmed the second layer to it to keep uniform glass thickness. I only filleted the rudder post as I have more work to do with it before I can tape it. My preference is to tape the wet fillets as the glass beds into it so nicely when it is wet.

    Missing is the photo of the tapered shim that I inserted under the skeg from the left side of photo #2 to square it to the bottom. Two temporary screws when used to hold the skeg in place until the epoxy set. Once set, I drilled and installed three 3/8" lags into the skeg from inside the hull. The skeg is the third leg of the tripod for when the boat dries on a tidal flat so I've attached it quite strongly to the hull.
     
  9. LP
    Joined: Jul 2005
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    Location: 26 36.9 N, 82 07.3 W

    LP Flying Boatman

    Flipped images.

    One of my pet peeves on this site is when members post images in an other than upright orientation. It's so simple to reorient the photo. Anyways, I'm not to piss and moan. I just noticed that when I view my images on an apple device, they get reoriented to their original rotation when they were taken with my iPhone. Argh! So, apologies to those of you that are viewing cockeyed photos on your apple devices. I will try reorienting them on my phone before loading them on my computer and subsequently, the web.
     
  10. LP
    Joined: Jul 2005
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    Location: 26 36.9 N, 82 07.3 W

    LP Flying Boatman

    Flotsam

    I found these little gems at Bed, Bath and Beyond the other day while on an errand for work. I've been using spatulas for fillet work. but they are very pliable so you have to get your fingers right down in your work. These little maestros have a hard plastic body for rigidity and a soft pliable edge that works like a squeegee. The convex side works great for laying down the fillet and turning it over works great for scooping up the excess. They can even be variable radius for those bow section chines. Woo! Woo! :cool:


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  11. LP
    Joined: Jul 2005
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    Location: 26 36.9 N, 82 07.3 W

    LP Flying Boatman

    The stern post.

    Build up of the stern post. Some cosmetic mahogany was added.

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  12. LP
    Joined: Jul 2005
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    LP Flying Boatman

    The fairing continues.

    An assortment of fairing photos. It's a slow process. I think I've finally gotten the mixture down right. Micro balloons are interesting creatures. You can pack so many of them into a mixture that the mix is too dry to use, but it still doesn't look thick enough to apply. If you can get it to peanut butter consistency, then you've gone too far. I'm adding between 1 in 4 to 1 in 3 parts cabosil to help with the consistency. I add these fillers until I get a taffy looking consistency when I draw the mixing tool out. Thicker that this and it tries to "ball" up on itself as you are spreading it. In the lower, leftish portion of the fourth photo, you can see where I have drawn the spreading tool over previously laid mix and it has balled up. I should have scraped it up and added some epoxy, but...I decided to let the sleeping dog lie. What's another coat of filler among friends? The right consistency makes spreading easy and I'm not getting in a big rush to get this done quickly. I try to do some sanding in the morning and when I tired of that and ready to call it quits, I spread some fairing compound for the next day's sanding routine. It's nice to have something you can count on....like sanding and sanding and sanding and sanding.......:rolleyes:

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  13. LP
    Joined: Jul 2005
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    LP Flying Boatman

    No more pics of filler. Sanded and filled today. The nice part is that the areas where I am applying filler are getting smaller and smaller. I'd say that 70% of the lower hull got its final application of compound today. The heaviest filling left to do is in the skeg area. Unintentionally, I've gotten the forward sections faired while the aft sections have dragged behind. And, the first sections outboard of the centerboard slot that I thought were faired are now not as good as I would like. It's the same as when I was working the upper portions of the hull. It seemed I would do fairing iterations and each iteration was better than the last. The upper portions of the hull dealt with fairing the planking before sheathing. The lower portions deal more with fairing around fiberglass edges and getting smooth transitions via filler fairing. Different techniques and different skill sets that get honed from the beginning of the job to the end.

    Today was a good day though. I'm starting to see some light at the end of the tunnel. At least as far as the lower hull goes. Then, it's back to the upper hull and it's final coats of epoxy. Woo! Hoo!
     
  14. SukiSolo
    Joined: Dec 2012
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    Location: Hampshire UK

    SukiSolo Senior Member

    Coming on nicely. Not really had much trouble with microballoons as long as they are nice and dry! Useful sometimes to vary the mix to suit, I tend to have a 'runny' mix if gravity will help smooth them out and a bit thicker where it won't. Sometimes a very thin coat of just epoxy on the surface prior to application will let the 'balling' type mix (too dry) you describe, flow better on application. It just makes that interface less of a problem and thins it for you marginally. Sometimes it reduces the possibility of air holes which you don't see til you sand back...;)

    Also worth using combinations ie with microfibres/colloidal etc and other fillers to suit. Just 'replaced' some broken foam cores on a couple of repairs with this type of blend as too awkward to get foam or ply in place. Once glassed in as per original build, the strength was fine as so much is just getting the glass skins to take the load. Not to mention repairing a repair (not mine) where the gelcoat was 6m thick because of crushed foam.......

    Nice to know the 'home run' is in sight.
     

  15. LP
    Joined: Jul 2005
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    Location: 26 36.9 N, 82 07.3 W

    LP Flying Boatman

    Suki,

    Thanks for stopping by. Helpful insights are always welcome. :cool:

    ------

    More filling and sanding over the last couple of days. Worked on some transom details and contoured the leading edge and bottom of the rudder post. I'm conflicted on the leading edge since it's right in the prop wash of the aux motor when it is running. I'm thinking I should go with a pretty small leading edge radius. It's always something, but I need to wrap up these little details so they don't hold up the bigger ones. :idea:
     
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