Building 417 from Plans

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jhippe
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Re: Building 417 from Plans

Post by jhippe »

Getting ready to head out on business trip tomorrow so got down to the shop to knock out a test block so that I can practice my rope work for rope stropped blocks. I am following a couple articles on the web at http://www.duckworksmagazine.com/02/art ... blocks.htm and http://bbprivateer.ca/?q=rope%20stropped%20block

I am using 8mm line so according to the information in the articles, my blocks should be the following dimensions:

Sheave -- 40mm diameter and 9mm thick
Block -- 60mm long and 24mm wide

I started by cutting a block a bit oversize out of walnut.
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Then cut the mortise for the sheave, cut the grooves for the line, and then shaped the overall block. The work was quick and dirty since this is just a practice block.
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A quick test of the line suggest that it will inlay well enough to prevent it from being dislodged.
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jhippe
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Re: Building 417 from Plans

Post by jhippe »

While on the road this week, I will practice making the grommets. I am using Posh line from R&W Rope. I went this way because I wanted the traditional look with synthetic line. I will seize the work with tarred nylon twine.
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jhippe
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Re: Building 417 from Plans

Post by jhippe »

My plan, at this point, is to make my own thimbles and sheaves. For the thimbles, I will use copper tubing cut and shaped using blow torch and ball peen hammers.

This is one I did a few months ago. It is too large for the 8mm line but will be useful for practice.
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jhippe
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Re: Building 417 from Plans

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The sheaves will be made out of lignum vitae. For my practice tonight, however, I used maple since I don't want to use the expensive wood until I get my procedures down.
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Good thing as the sheave I made tonight had issues. After cutting the sheave out using a hole saw, I put the sheave on a bolt and chucked the bolt into my drill press and tried to free hand the groove using a rat tail file...
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I haven't diagnosed the reason, but you can clearly see that the groove is wandering all over the place. I think that my bolt that I was using is not quite straight.
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jhippe
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Re: Building 417 from Plans

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Tonight I did my first practice on making the grommet and seizing it to the block. The first step was to unlay the line to provide one strand from the 3 strand rope.

According to the article found here http://bbprivateer.ca/?q=rope%20stropped%20block the length should be 3 times the circumference of the grommet plus six times the circumference of the rope. As you will see, geometry is not my strong suit so I mis-measured and ended up with a grommet that was too big.

After unlaying one strand, I proceeded to make the grommet. This is an interesting task as one must wind the strand back on to itself following its "memory" of how it lay prior to the unwinding, all the while trying to keep the lay of the strand consistent. I was pretty pleased with the result, even if it was a bit lumpy... If you look closely at the bottom and upper left you will see where the lay of the strand is uneven. You will also see the ends of the strand from the splice prior to me trimming them.
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Next up came the whipping of the splice. Before I did this, I rolled the splice between my hand and the floor which helped even out the splice. The slice is pretty long so it takes a lot of whipping. Again, I was pleased with the results.
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The last, and trickiest step was seizing the grommet to the block. What I found difficult was holding all the pieces while trying to wind the whipping line around the grommet while also applying enough pressure to close the eye strongly enought to capture the block and the thimble. I was able to do all this but it is not pretty. Also, as you can see, my mis-measurement caused me to end up with too long a neck between the block and the thimble.
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I ended up not having enough twine to complete any frapping turns so I just tucked the ends into the block for the picture...

I learned some good lessons from this practice round. First, I will need to get a more accurate measurement for the size of the grommet. I think I was too worried with it being too small that I added too much extra "just in case..." The making of the grommet and the splice will improve with time.

Second, I need some sort of holding system for when I am seizing the grommet to the block and thimble. Here in the hotel I am limited but I think I may be able to rig something up with some line. One line going through the block and tied off to a leg of a table and another line going through the thimble and tied off to another anchor point.

My thinking here is that I want the grommet under tension as I seize it. This will ensure that the grommet is seated into the opposite side of the block and grommet -- the sides away from where I am seizing the grommet. The thimble, which i thought would be too big, ended up being a good size.

The final lesson, which is a constant one for me, is to allow myself to make mistakes and be comfortable with the learning process. I always find myself becoming frustrated in the middle of learning a new procedure. This frustration leads to doubt and second guessing my decisions to make things on my own. "Why the $%&* didn't I just buy the blocks?" Or whatever it is I am learning to make. It sure would be easier. At the end of the day, however, I know that I want something that I built. Flaws and all.
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Jason Builder
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Re: Building 417 from Plans

Post by Jason Builder »

Wow, you are going to the next level. You will really have something to show people that step aboard! Looks great. As always your tools look great, nice drill press table.

-Jason
-Jason

Builder of SCAMP#349 "Argo": Build log at http://www.argobuilder.com
Caretaker of these fine ships:
-SCAMP "Argo"
-1981 Compac 16 Pilothouse "Lillyanna"
-Old Towne 16' Canoe
jhippe
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Re: Building 417 from Plans

Post by jhippe »

Thanks Jason. I am enjoying the entire process. The drill press is a Wen. Not high end but gets the job done.

Round two of practicing the rope grommets last night. Again, unlay the rope.
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You can see the "memory" still in the line which is what guides the re-winding of the grommet.
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I think I got a better lay on this grommet.
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jhippe
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Re: Building 417 from Plans

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Next step was to whip the splice with the tarred twine. The tarred twine is nice to work with in that it will stay put due to the stickiness of the tar. It is a bit messy and my hands got a bit blackened but nothing too bad.
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I think that this came out better than the last one but you can see that I am still a bit inconsistent with the tension resulting in the left hand side being a bit larger in diameter than the right.

Now for the disappointing part. This time I tried to be really careful in measuring to get the thimble closer to the block. Well...I got it too tight. So, I am taking the Goldilocks approach...first one was too big, second too small...
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You can see by the tar lines on the rope that I still tried to seize it to the block. In the process the it twisted the line a bit and go the thimble off center in the spliced area.

Lessons learned this time. Working in the hotel means that I don't have access to all my tools and other supplies. I would have benefited from having a sharpie to mark exactly where I want to start the winding process of the grommet. It was also difficult measuring the precise distance around both the block and the thimble including the space between the two for the seizing. When I get home, I will somehow attach the block and thimble along with a spacer between the two to take the measurement. The other lesson to let the rope "speak" to me as I am winding the grommet. There is a natural way it wants to lay, so follow it. That being said, the winding around itself is a bit different than the winding of three strands together. This means that about 1/2 way around, a bit of adjustment is necessary. Not much but just a bit. If you look at the bottom of the grommet, you will see this adjustment. Hopefully over time, I will get this to be a bit smoother.

When I get home I will also pull out Brian Toss's "Riggers Apprentice" to do some additional learning.
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jhippe
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Re: Building 417 from Plans

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Today I am back home so back to the main focus of building the boat. Today was a milestone as I began building in three dimensions. I have to admit that I have been somewhat dreading this day for fear that I would find some major flaw in my pre-cut parts. With one exception (more on that later) everything came together very well.

There was a fair bit of faffing about as I tried figuring out how to get the bulkheads to stand up during the dry-fit stage. Also, things weren't quite lining up when I tried locating the bulkheads where I was measuring to the plans.

I set up all the bulkheads and then put in the port seat longitudinal. So far, so good. When I got to the starboard longitudinal, it would not seat down into the centerboard slot. It was sitting about 5-10 mm too far aft. Somewhat bemused, I circled the boat a few times scratching my head. Then I noticed that the aft end of the seat longitudinals were sitting proud of the back of the boat. Well, one way to fix both problems...I shoved everything forward until the seat longitudinals were flush with the aft end of the boat and the starboard longitudinal seated down into the centerboard slot. Voila! It all fit. A few checks with the level to make sure it was all plumb and all was good.

Well, not everything. The aft end of the bottom was not matching up with the curve of the seat longitudinal. It was sitting too low. I noted that the distance seemed to be the same on both sides so concluded that my building jig was probably off a bit. Therefore, I shimmed up the bottom to meet the seat lingitudinal. I will double check with the transom and the aft end of the planks just to make sure but it looks right to me.

All the floor supports line up as do the seat tops.
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jhippe
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Re: Building 417 from Plans

Post by jhippe »

Now to the one problem. The centerboard case carries forward too far. I have checked and re-checked the measurements and they are correct as per the plans. B4 is located 2039mm from aft end. The plans say to cut the centerboard case to 2064mm form aft end. I did not catch this inconsistency until today. Right now, I am thinking that the plans are incorrect and I cannot find anything that gives different measurements or discusses this. Doesn't mean it does not exist. Regardless, the problem still stands. I have a hole in the bottom of my boat where there should not be one.
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This is not insurmountable. At this time, I think that my course of action will be to glue a backing plate over the hole. Then, when I turn the boat over I will fill from the bottom starting with a small plywood filler piece glued into the offending hole. This will be covered with epoxy and fiberglass so I believe it will be ok. I will continue to contemplate alternatives and am open to suggestions from others.
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