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Amphion Drafts Mark III


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#41
Dupree Allen

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Screen Shot 2016-10-31 at 7.41.12 AM.png

 

Thank you for your inputs. All have provided valuable information. One last issue.....can anyone explain the vertical dimension off set above the object. I've used up two evenings trying to remedy this. My inquiry to TC have thus far gone unanswered. Probably something simple. Will try to send screen shot.


Edited by dallen0121, 31 October 2016 - 12:52 PM.

Dupree

 

"A slow steady hand conquers a fast shaky mind" - me

 

 

HMS Triton 1:32 Cross Section


#42
Matrim

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You might be better of posting a topic in the cad forum as you may have more chance of reaching someone who uses turbocad with the mac.

 

Also try posting in the turbocad forums. Again you are more likely to find a mac user there and the forums are generally more responsive than contacting the company.


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Ours is a life of constant reruns. We're always circling back to where we'd we started, then starting all over again. Even if we don't run extra laps that day, we surely will come back for more of the same another day soon. - Joe Henderson


#43
Matrim

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Another (slow) update. I have started on some build plans. The following are provisionally measured at 1:48 scale though this may be adjusted later after more consideration.

 

We have two keel build plans. The first showing the side

 

keelside.png

 

and the second the top

 

keeltop.png

 

The False Keel will be an easy addition along the same lines then I will probably move to the stem plans. You will notice the first plan has a 'green L'. I tend to add these to build plans at the correct scale so 1:1 those two lines each measure 48 inches in this case. When printing I can then measure those lines and they should be exactly on 1 inch. If so then no problems with scaling has occurred..


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Ours is a life of constant reruns. We're always circling back to where we'd we started, then starting all over again. Even if we don't run extra laps that day, we surely will come back for more of the same another day soon. - Joe Henderson


#44
BANYAN

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Very nice plans you are developing Joss; they should make building very easy with such detail.

 

I have been looking in regularly but not posted.  

 

cheers

 

Pat


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#45
wrkempson

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Did I miss the taper?


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#46
Matrim

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Indeed as these plans dont have it.. (most of the plans posted in detail are missing something) though in this case that is less an attempt to deliberately lose something as a decision not made. Basically when I last looked at building on the original plans I had decided to taper after completing the stem and false keel under the perhaps mistaken idea that it would be easier.

 

Perhaps it would be better to mark the taper now and cut it accurately on all pieces..

 

Just in case here is a revised with the start of the taper marked with a red vertical line...I am cutting corners slightly by making it start just after the joint (in both cases) so if this is very wrong then please say!

 

keeltop2.png


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Ours is a life of constant reruns. We're always circling back to where we'd we started, then starting all over again. Even if we don't run extra laps that day, we surely will come back for more of the same another day soon. - Joe Henderson


#47
druxey

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Keel taper is a vexatious question. No source I've read specifies exactly where it begins. I suspect that it starts where the cant frames begin, but have no hard proof of this. Anyone else have more information?


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#48
vossiewulf

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Indeed as these plans dont have it.. (most of the plans posted in detail are missing something) though in this case that is less an attempt to deliberately lose something as a decision not made. Basically when I last looked at building on the original plans I had decided to taper after completing the stem and false keel under the perhaps mistaken idea that it would be easier.

 

Perhaps it would be better to mark the taper now and cut it accurately on all pieces..

 

Just in case here is a revised with the start of the taper marked with a red vertical line...I am cutting corners slightly by making it start just after the joint (in both cases) so if this is very wrong then please say!

 

Has anyone ever taken a run and automating this? We (and I mean human race) have thousands of these plans in a relatively consistent format. I see no impossible to overcome challenges in creating a tool that can output to formats importable by CAD and creative modelers (MAX etc.), by extracting the station frame curves and positioning them on a correct keel and generating a skinned/solid model. If wer can extract the station frames, we could easily tween the values between station frames to generate the intervening frames.

 

I'm not saying it would be easy, but I think it's doable, and it seems to me we have enough interested parties and groups that it might be worth doing - imagine there being a library of skinned and solid models with correct hull forms, wales, gunports, would have to draw the line at the head and the stern, too variable and complex. But still if we got that far, modelers, historians, games and movie people, all could access all of these sailing models for whatever purpose they need. And the processing would still require some human input to indicate the correct areas to scan for the curves and which is bow and which is stern, and marking the keel location and length and probably a couple other steps to prime the tool for each unique plan.

 

Only step I'm iffy on is automated generating of spline-based curves for the station frames, I'm not sure that I know of a product doing that, turning 2d drawings into vector/spline-based lines. I have some idea of companies I could ask who should be able to do it. But also I'll see if I can track this guy down, this was a proposal to do the exact same thing for old rocket parts.(FYI - that's a PDF). This is just the proposal, not clear he did it.

 

Anyone else know of existing tools/companies/researchers who might find this problem interesting?


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#49
Matrim

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Interesting concept though i don't think it is doable. Perhaps for modern plans with no 'give' but for anything on old paper you have to spend a lot of time making certain the plans tie up to each other correctly even before you get to drawing the frames.

 

The other problem is more specific and directly related to the taper quote. We do not have a definitive way of doing these things and my way is almost certainly a fudge. When build plans are made you spend a lot of time deciding how much detail you want to put in and there are always tradefoffs between realism, ability to draw in scale and time.


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Ours is a life of constant reruns. We're always circling back to where we'd we started, then starting all over again. Even if we don't run extra laps that day, we surely will come back for more of the same another day soon. - Joe Henderson


#50
vossiewulf

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I sent some mail to the guy who put together that presentation, will see if he answers. Matrim I wouldn't anticipate you could just point the tool at a bunch of plans and walk away, there would still be a degree of human input to make sure the plan is clean and marking locations of certain items before it could make an attempt to build at the very least.

 

Are you saying you've found the drawings are stretched somehow? I thought generally speaking the paper used for these plans was fairly heavy and would be resistant to something like that. Yes, that would be very difficult to correct.


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#51
mtaylor

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If the plans are original (or copies of, even 10 years old), there can be distortion due to things like humidity and temperature.  


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Mark

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#52
smatsik

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Just catching up on this. I am very impressed with your work and have got a lot of ideas for when I work from old plans.

 

One thought on the taper you can use as a check. Fincham lists keel taper as 1/8 inch per foot on each side in his book from 1825. That is a taper of 1 inch overall every 4 feet so that should give an idea of where the taper should start. At the least it can serve as a sanity check.

 

Hoss


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#53
wrkempson

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Hoss, can you provide the page where this is found?

 

Wayne

 

EDIT:  Found it in An Outline of Ship Building by John Fincham, 1852, p. 72 for the fore foot.


Edited by wrkempson, 28 December 2016 - 11:00 PM.

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#54
smatsik

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Wayne,

 

In the 1825 Second Edition I got from Google it is page 9, Section 3. Did you get the 1852 version from Google. I will have to see if I can get it and check for what is different. Sounds like there are a lot of changes.

 

Hoss


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#55
wrkempson

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Many, many thanks.

 

Wayne


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#56
Matrim

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Just returning to this after Christmas. I have been thinking about Hoss's taper recommendations. Taking my frigate she should be 15 inches wide amidships and 12 inches wide at the post/rudder. This is only a taper of 1.5 inches. My current taper starts (at the stern end) around 24 foot from the rudder making it a fairly gentle incline.

 

Taking the above recommendation then 1.5 inches should take up around 6 foot so 72 inches. This is a much sharper incline but makes some logical sense due to the ships base shape

 

Anyway throwing those locations onto one of the draft plans we get

 

KeelShot.png

 

The left most lime green line being 6ft and the rightmost being the current taper start point.

 

Hmm I am tempted to re-do the keel and false keel plans to see what the taper would approximately look like and perhaps cut it out of some scale wood to see as well.


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Ours is a life of constant reruns. We're always circling back to where we'd we started, then starting all over again. Even if we don't run extra laps that day, we surely will come back for more of the same another day soon. - Joe Henderson


#57
druxey

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My gut feeling is that your current taper seems right: the other would be much too abrupt. My vote is that you are good.


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#58
wrkempson

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By Hoss's citation the taper would begin 4 feet distant for every 1 inch differential between the midship siding and the end siding.  In your case, 15-12=3  and so 3X4=12.  Hence, the taper would be 12 feet from the end, not 6 feet.  I think you may have halved the 3 inch differential unnecessarily. 

 

Twelve feet still seems too short for my viscera, but if you follow Hoss's formula that's what it is.

 

I have argued elsewhere for a different way to view the taper, but for the present I am no longer as certain as before.  It's just that 12 feet is awfully severe to me.

 

Wayne


Edited by wrkempson, 04 January 2017 - 07:44 PM.

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#59
wrkempson

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Upon looking at Fincham again, his words are "It [the keel] is parallel in breadth or siding, excepting towards the extremities, where it is reduced from two to three inches; in the proportion of 1/8 inch in a foot on each side."

 

Ignoring the archaic punctuation, this can be read to mean that the taper extends over a length of one foot per 1/8 inch of differential between the midship and end siding of the keel.  Thus, a total taper of 3 inches would begin at a length of 24 feet from the end.  The formula in Finch (a foot to 1/8 inch) does not describe the angle of the taper but is a rule to establish where the taper begins.  So, there is a taper on both sides that begins at a distance of a foot per 1/8 inch of the total differential.

 

So, I guess I would amend Hoss's formula and suggest the taper begins at 24 feet from the end (if we follow Fincham).

 

I can think of one reason to ignore Fincham for earlier vessels, but I'm not sure of it enough to suggest it here.

 

Wayne


Edited by wrkempson, 04 January 2017 - 08:17 PM.

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#60
druxey

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Wayne: your argument is a compelling one. And it accords more or less with my hunch as well!


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