Blackrock 24 (Build)

Great thoughts on the mast step solution. Any idea what white plastic cutting boards are made out of? I have an old one tucked away waiting for a new purpose in life. :idea:

Latestarter: Thanks for the clarification on the colloquialism. The things you learn on the boat forum.

 

I have a few cutting boards, that I use for sheaves (the first one I stole from the kitchen). Most are HDPE and easily machined, though you have to "finish" the surface afterward, as it can get fuzzy. Plastics are usually marked as to what they are, with at least a recycling symbol. I use these plastics on a lot of things and a mast step is common, especially if rotating.

 

Over due update.

I've been making progress, but my smart phone cord is screwy and needs to be replaced so transferring picture to my computer is a real PITA.

I'll try to get things caught up.

For now, I've got the mast step worked out. I've made white oak cheek pieces that should take the brunt of the abuse from stepping the mast. Then there are backer pieces made of douglas fir to provide additional lateral support to holding mast loads. The mart step will be wet as I don't plan to seal it at the partners. This necessitates drains for the step. My solution for adding drains to the step was to bed some poly tubing in thickened epoxy, let it cure and pull the tubing out. This saved drilling drain holes and having to go back and seal them. The bedded tubes were flexible enough to be pulled from the hardened epoxy and leave nicely sealed drain holes. In the picture, the tubes are still in place,



Looking down (up) from above (below). Note: I've forgotten to remove a temporary screw. I was going to place a bumper plate at the base of the step. but my thoughts are running towards multiple layers of biax that run up either side of the step help spread the lateral mast loads over a wider area. I'm thinking four layers of 17 oz. biax that will run up alternating step sides in alternating layer. This will also harden the area considerable.



A side view of the step drain with the tube still in place. I plan to place drain holes in the hull that will be co-linear with these drain holes. The idea is to be able to use a straight piece of something to clear out the drains should they become clogged.

 

Planking continues.

Edge set was becoming a problem and it was become apparent that I was going to lose a lot of plank material to tapering if I was to try to let the planks run more naturally. I bit the bullet and ripped a portion of my remaining plank stock in half lengthwise. This gave me plank material the was more or less equal in both directions. Or more simply, a much more compliant plank material. With the higher density of seams, I also chose to step back from my back filling method and applied wet epoxy to each plank as it was applied to the hull. I ran pairs of planks aft and each successive pair ended a little farther forward in anticipation of subsequent planking. At this stage, I am planked down below the waterline in almost all areas of the hull. I have a few cedar planks remaining and will use them before switching over to my spruce and fir planking stock. The spruce and fir planking is denser, heavier and stronger than the cedar and will make for a tough lower hull.

Note the loose planks running aft from the attached pieces. I am attempting pull in the ends of the installed planks to make the run true to plank shape that will extend aft. There was a strong tendency for the plank ends to splay out at this point and the floating planks were clamped in place until the epoxy set on the attached pieces. I may have been only partially successful with this plan.

 

Usually, just before you get to this portion of the hull you make a decision about where to stop and start the planking runs anew. The common path is to plank from the sheer down to about the LWL, then make a common cut, across all the planks. Next you'd continue planking to the centerline or more often, start planking from the centerline to the LWL cut. With the shape (that I know is there) you're about to run into, I'll bet twist is becoming a real *****. Maybe the description isn't good enough, but I don't understand what's going on with the last image you've posted.

 

I'm actually farther along than the last picture indicates and I have transitioned how I am laying the planks. I'll get a couple more pictures in shortly. The aft ends follow the established lay, but I have been trimming the forward ends to lay into the forward planks (almost as you have suggested with the common cut).

The last bit of planking was half width pieces for the edge set, but the aft square edge seemed to be flairing out a bit. Using my plank clamps and lengths of planks, I was trying to draw them back in to where they should lie. The clamps I've made being the planks into alignment within the plane of the plank. Clamping a length of plank to another and then clamping the loose end into place twists and bends all of the pieces into better alignment while the glue sets. Once the glue is set, there is not a lot of movement in the planks do I'm trying to avoid plank ends that stand to proud, only to be shaved off in the fairing process.

I almost went with the common cut of my own accord, but chose a slightly different approach that you'll most likely see in my next post.

 

Here is about where I am at now. The last half dozen planks(in the photo) are nailed and ready to be filled. I've transitioned into my below waterline planking. You can see the change in plank orientation at the bow. I've started hand nailing the planks as it's getting hard to judge the angle of the nail gun and I'm getting too many stray shots. It's takes a little more time. but there is a certain satisfaction with driving a nail home. And, if the nail starts to go astray, I can stop, redrive another nail and pull the wayward one before it becomes a problem. I've got about 8" of plank to go at the stern and slightly more at the bow. I am going to get to a point where I'll be unable to drive any more nails and will have to resort to other methods for fixing the planks until the glue sets. Exterior guides temporarily screwed to the hull comes to mind.

Between nailing and gluing sessions, I spend time getting to know my hand plane and sanding board more intimately. Most of the planked hull has had a rough fairing job done too it and a finer fair and sanding in the more easily accessible locations. The lower locations (or low-cations )can be a beach to work on and I'm thinking about converting the support fixture to a centerline pivoting affair. At this point, I feel the hull is locked in and no longer needs an extensive support network. This will let me raise and lower my work surface as needed. For the longest time, I felt I place the fixturing too low and an added foot in height would have been really useful. Now that I've rounded the bilge in the planking process, the work surface is getting too high. I guess it's all working as planned since a build of this size is going to have those extremes. The tipping fixture, if I follow though with it, will offer a other advantages besides adjustable work heights.

Access under the hull will be improved. The side supports will go away to allow access to frame/hull joints that are currently blocked.

If I can keep my horses reined in, I may even start the filleting and taping process before the roll over. My experience with working overhead earlier in the build was a much more positive experience than expected and reaching up may be preferable to hunching over and doing fillets at my feet. Less chance of stepping into a finished seam, too. This may also lead the way to installing some interior furnishings with a more positive attitude (physical and mental) while the hull is still inverted. I believe that it is better for me to be working right-side-up on an inverted hull than it is for a right-side-up hull to be working on inverted ME.

 

Work, work, work...

My boat building is severely interrupted! Some gluing, some planking. A couple of shots of where the planking sits. One more full width course at the stern and a few more at the front. Edge nailing gets real interesting when you get down to a couple of inches of swing room. I'm toying with alternative plans for securing the planks until I get the seams glued. I think that for the last couple of courses, they will get nailed to the frames (where there are no limbers) and I'll drive screws into the gaps between planks to lock them against each other until I get the seam glued.

I believe that progress will slow from here until fall sets in. I've got training to do for work that will keep me occupied for a while. A new type rating in a Lear 45. The LP will rise again. My original screen name was Learpilot, but I had it shortened to LP because the other smacked of arrogance .... or something. I prefer being an explosive hydrocarbon anyways. Summer is the time for boating, too. So why build 'em if you don't use 'em? I was hoping for a summertime roll-over, but that may be slipping quietly away. You gotta keep the priorities in order!

 

Back at it.

Back at it. I got my new ride. Not really mine. I just get to play in it.



But, you're not interested in airplanes so here is the good stuff. The planking is almost finished on one side. I'll get these glued in and come back finish the little filler pieces to call it good. I call these photos "Adventures in clamping" as you can see there is quite a lot going on to set things in place until these can be glued. I've gotten to the point where it's almost impossible to edge nail any of the planks so it's clamps and screws until the glue sets. The fir planking gets paint so I'm not concerned about some screw holes. I'm screwing forming to the exterior of the hull and screwing the planks to theses forms to hold them in place. Intermediate to the forms, I am placing screws between the planks to act as spacers and also to hold the planks in alignment between the forms. I used plank cutoffs for most of the forms, but the bow sections have too much curvature so I used a double layer of thin wood stock to bend a curve form to screw the planks to.

 

Tilted

I've adjusted my support fixtures to centerline support with lateral stabilizers. This lets me tilt the hull one way or the other and presents different areas of the hull to me for friendlier working heights. This was such a welcome change that I spent big chunks of a couple of days doing the rough fair of the port side above the turn of the bilge, followed by a fine fair. It is amazing how much a block plane talks to you when you are working the hull like this. The first rule is: keep the blaster blade sharp! Hand planning does no good with an iffy blade. The first cuts are fairly deep to take off as much unfair material as possible and to work the hull surface into a relatively cohesive plane. Working at 45's the plank run, in both directions completed the rough fair pretty well. The hull surface had a coating of epoxy from the seam filling process, so when the epoxy coating was completely remove, it told me the rough fair was complete. Once roughed in, it was time to sharpen the blade and set it really fine so that only very fine sliver came off and only at the high spots. This stage was done with a variety of strokes. I still used the 45's, but some places called for running with the grain. In other places, 90 degrees. It amazing how little of a bump is noticeable to your hand when you sweep it across the surface of the hull. Fractions of a millimeter! With a very fine setting on the plane, sometimes I would work the area of the hump at a 90 and sometimes at 0. There is more tendency to cause unfairness when planning with the grain in areas of high curvature like the turn of the bilge. The plane blade is a straight edge so it leaves little flat areas (facets) all of the way around the turn if you are not careful. A carefully tuned and operated plane will only take off the high spots as it is worked obliquely across the grain.

I followed up the planing with some long board work. Not that long, though. About 19" to be more precise. I've been using 21" sanding belts and the is the length that I get. These suckers are tough and I did not notice any appreciable loss in cutting ability of the belt over the whole side of the hull. I messed with the lower portion of the hull also, but decided not to do any long boarding there until I get the other hull side fairer. The cedar is no match for the sanding belt, but the fir on the lower planking may be more of a challenge. I'll save the heavy work for last and maybe the single belt will do the job.

I'm still not done with the planking. Close, but not quite. After my fairing excursions, I started fitting the last few planks. One more day of fitting and I think the planking will be done. Every one of the needs to be spiled so there is going to be a lot of cutting and fitting. That's all for now.

 

If you haven't seen them yet, try some of the ceramic coated papers. They cut a lot better, stay cool longer and are much more durable. They're available in the usual shapes, DA, belt, sheet, etc.

 

No progress, just a couple of photos.

A shot of the hull typed. Makes for easier working on the bottom on the low side and easier access towards the sheer on the high side. The low side is moderately faired in this photo while the high only has the initial rough fair. It also makes getting under the hull easier for access inside the boat.



And a little something on the artsy side. I think....

 

Momentous!

For me anyways. The hull is planked!

I can seriously start fairing the hull, now. Fortunately and conservatively, the hull is about 50% faired from previous days of "I don't feel like planking today."

The last few planks were a pain as they all had to be spiled to the central hull unit and conventional spiling wasn't an option. I ended up taking width dimensions every 6" and transferred them to the plank for cutting. Filling the seams became a two person job as the hull was pretty much sealed up and a second set of eyes was needed on the inside of the hull to confirm adequate seam filling.

All said and done, my only real myopic moment was in the transition to the modified run of the bottom planks. I should have run the forward sections down(up) the hull further before the transition in the bow sections. There was still a fair amount curvature on the forward sections of the hull and the new lay of planks did not take to this curvature well. It left a bit of a "corner" at the transition and some awkward lay in some of the planks. Getting a fair curve in these areas meant a lot of material removal and thinned sections at the transition. I will treat it somewhat like a taped seam on the inside and put in an epoxy fillet to thicken the section to be followed a biax tape for strength. Then the inside and outside will get glass cloth per the norm.

 

How much epoxy and filler did it take to fill all those seams?

 

That's a painful question to ask, Paul.

A lot. I may have used an entire six gallon pack on the seams plus some minor bonding of planks to frames, bulkheads, stem and transom. The early seams took less, but as I rounded over the turn of the bilge, I had to thicken the mixture more so the seams got wider to get the mixture to be worked in with a reasonable amount of effort. By the end, I was putting in a cup and a half of fillers into 6 oz. epoxy. 1 cup of CS for strength, 1/2 cup of wood flour for color and 1/2 cup of microballoons for post cure workability.

I strengthened the mix when I got to the fir planking. I had a little higher concentration of balloons with the cedar planks.