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USS Constitution - Model Shipways

Grok isn't much better on that front. You have to challenge all responses. I wish I had kept the pictures of the deck arrangement behind the mast on the spar deck that I asked him to provide. When I told him he didn't know what he was talking about, he apologized and said you're right, and then sent me to a couple of websites where I could get better information.
 
Chat GPT also makes information up. Not good. I think I am going to treat AI like Wikipedia. Lord knows the source of the information presented. I also noticed that sometimes you are sent into a neverending loop of information that turns into jibberish. It looks good but when you dig deaper it is actually garbage. My attitude has definitely changed about it.
 
well here is my humble attempt at measuring rope tension it the machine
The idea is to create a downward force on the middle blue pully so that the loadcell underneath it can register a value. I am thinking that I can adjust the wingnut on the simple clutch mechanism that I described in a previous post to maintain a constant value on the diplay. Hopefully it will work. Lots of unknowns at this time
The other option is to measure the takeup frequently which doesn't provide a continuous measurement. You have to manually calculate it
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None of this stuff is proven to work. I just wanted to get some information in the log. If the tension thing doesn't work then I'll have to manually measure the takeup which I should do regardless.
 
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well, the pulley thing seems to work. as the tension increased the number on the display increases. that's promising, I think.
I think the number on the screen is grams, but the loadcell is not calibrated, nor do I think it needs to be given that this magic number follows with the tension.
I know there is a relationship between the tension and the load cell weight but I don't feel like getting into that. I don't think it is necessary.

Lets see if I can play with this tension parameter a little bit as well as the speed ratio between the planetary head and the takeup spool.
I want to generate rope that is very stiff to very soft. It's probably not just the machine's parameters that dicate this but I am going to try to make it that way for fun. For example the amount of tar put on the ropes would affect this property as would the rope material. Also, stays are usually served which definitely affects the ropes stiffness, if you will. I wonder if there is a way to measure stiffness...

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chat gpt shows me a jig for the purposes of measuring stiffness. I suppose I could try and build it and see if I can get what I want. Is it worth the effort? Probably not but I am having a blast so why not. I'll get to the boat eventually. Hey. I painted the lower masts and the tops so I am not completely procrastinating. lol
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Hello Jack Sparrow, this is my first attempt at a patina hull. The paint I used can be seen in the attached photo. I tested several strips before applying to my hull. Ragnar
IMG_20260803_102316458_HDR.jpg
 
Der Alte Rentner said:
I know you've mentioned it before, but who made that device? It doesn't look like the one I was looking at from Europe.
Click to expand...
well i looked but i can't seem to find the receipt from where i bought that thing. But it has been heavily modified to make it more stable because the original design is quite "clunky". For example. I stopped the center gear from turning because it isn't supposed to. I think it's called the sun gear. I also anchored the shaft of that gear so that it doesn't move in and out. Ridiculous that I had to do that stuff but anyways I did

I am contemplating 3d printing all the components and making a new machine for fun of course.
 
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Jack Sparrow said:
well, the pulley thing seems to work. as the tension increased the number on the display increases. that's promising, I think.
I think the number on the screen is grams, but the loadcell is not calibrated, nor do I think it needs to be given that this magic number follows with the tension.
I know there is a relationship between the tension and the load cell weight but I don't feel like getting into that. I don't think it is necessary.

Lets see if I can play with this tension parameter a little bit as well as the speed ratio between the planetary head and the takeup spool.
I want to generate rope that is very stiff to very soft. It's probably not just the machine's parameters that dicate this but I am going to try to make it that way for fun. For example the amount of tar put on the ropes would affect this property as would the rope material. Also, stays are usually served which definitely affects the ropes stiffness, if you will. I wonder if there is a way to measure stiffness...

View attachment 640753
Click to expand...
I removed the end pulleys as they didn't serve any purpose. I thought I was going to need them to make the rope more stabile but just the middle roller seems to be enough. I am measuring tension which apparently this load cell is capable of doing. Who knew?
 
For sake of completeness, here is the geometry used for the system.
Clearly the Tension forces in the two segments on the left and right of the pulley are not equal. So the loadcell reads the resultant force of the two. I just want to keep it constant at a desired value. Let's see what I can do with this. One thing to note, I think, is as the spool fills up, the 13 degree angle will change. So there will be a geometry effect on the force on the loadcell.

1791062263115.png
 
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You mentioned the end pulleys not serving a purpose, but a pulley/roller between the center pulley and the take-up spool would negate the changing angle mentioned in your second post. A thought, but I don’t know anything about the physics of rope-making.
 
Namabiiru said:
You mentioned the end pulleys not serving a purpose, but a pulley/roller between the center pulley and the take-up spool would negate the changing angle mentioned in your second post. A thought, but I don’t know anything about the physics of rope-making.
Click to expand...
good point but all it does is gives me T1=T2. and so F=T if the angle is set to 30 degrees on both sides. I suppose that makes it easier to get an exact value for the force, and makes it easier to control the tension. But I have no plans of filling the spool too much so I am thinking that the angle effect will not be as pronounced. Having said that I suppose it's not a big deal to buy more rollers. I am just tired of waiting and want to get going.. oh and there is less snag in the rope with only one roller.

Thanks to the freebody diagram from chat gpt. Makes me sound like I know what I am doing but I am actually flying by the seat of my pants.

I am now actually thinking of buying a line counter. they are not expensive and it would give me usefull information.
 
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