MG20 dimension

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Rogerogrant
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MG20 dimension

Post by Rogerogrant » Sat Mar 21, 2020 3:35 pm

Hey y'all!

I'm drawing out the MG20 hull and have a quick question about the final dimension (moving from transom to bow) for the bottom panel. Since a picture is worth a thousand words.

Image

I'm sure I'm just failing to understand one of the conventions of how things are measured....
Thanks y'all! I hope everyone is safe and healthy.

-Patrick



OneWayTraffic
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Re: MG20 dimension

Post by OneWayTraffic » Sat Mar 21, 2020 4:04 pm

Hi. I don't have those plans but it's similar enough to the ones I do have. Sufficient dimensions are given to draw the panel. If you use a batten to fair the curve then the point will be where it needs to be at the intersection.

I have fair math skills, assuming the top line is straight then I get the 'missing' length as 212mm. I don't think that it really matters. Just plot the points, fill them in with fair curves using battens, and it will all fit. Unless you have a CNC there is no way that you are going to draw or cut accurately enough for it to matter. A 5mm gap is not a problem, anything less than a 3mm gap I'd be running a saw through it to make one.

Dougster
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Re: MG20 dimension

Post by Dougster » Sun Mar 22, 2020 11:04 am

Never saw those plans but I'm with Oneway. I'd call it the "let it happen" approach. Just draw the lines fair with a batten and where they intersect is the bow tip. Let it happen :D

Dougster

Rogerogrant
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Re: MG20 dimension

Post by Rogerogrant » Sun Mar 22, 2020 1:25 pm

:D Thanks y'all!

I'm actually drawing it out in Rhino (CAD program) right now, but OneWayTraffic's 212mm number worked out - close enough for rock n' roll at least.

-PT

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Re: MG20 dimension

Post by OneWayTraffic » Mon Mar 23, 2020 5:49 am

No worries. Jacques once mentioned that nearly all lines in his plans are straight lines or parabolas. You could try fitting a parabola through the curve and see where it ends up. That was my first thought, but I'd need another point on the bottom to do it.

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BarraMan
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Re: MG20 dimension

Post by BarraMan » Mon Mar 23, 2020 8:54 am

I have the M20 plans. Don’t recall any measurements being missing. I’ll take a look at the plans tomorrow.
Good to see someone building an M20 - it’s a great hull!

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BarraMan
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Re: MG20 dimension

Post by BarraMan » Tue Mar 24, 2020 1:34 am

Don’t recall any measurements being missing.
But heh, it was a few years ago, and I am getting old! :D

Your 610 mm is correct, and I believe the missing measurement is 180 mm.

Image

I up-scaled the hull by 10%. The numbers in brackets are the standard dimensions x 1.1. The number in brackets below the 180 is 198 - which is 180 x 1.1.

I look forward to following your build. Lots of pics please! There appears to be only two Mangusta builds documented here, although I understand that several others have been built. Mine is not a standard Mangusta 20, although the build by 'fmiles' is.

Regards
Lee

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jacquesmm
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Re: MG20 dimension

Post by jacquesmm » Tue Mar 24, 2020 10:54 am

Lee's reply is correct.
Jacques Mertens - Designer
http://bateau.com

OneWayTraffic
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Re: MG20 dimension

Post by OneWayTraffic » Tue Mar 24, 2020 3:40 pm

Ahh out by 32mm. Of course the top line wouldn't be straight, but I had little to go on. :)

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