Author Topic: My Official build thread. 27 1/2’ GA  (Read 179091 times)

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Todd j

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Re: My Official build thread. 27 1/2’ GA
« Reply #330 on: September 19, 2019, 10:43:27 AM »
Groovy.   I’m sure the numbers are right.  It might be my eyes playing tricks on me.  Upside down boat.   Can’t get the whole picture inside The building.  No one else unhappy.  Gotta be me.  FWIW.  I did measure with a drywall square perpendicular to the chines as prescribed

json

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Re: My Official build thread. 27 1/2’ GA
« Reply #331 on: September 19, 2019, 01:20:12 PM »
Todd, I feel like there is a bit of a hump on mine too, but like you I can't really get a good enough look at this point to know if I am happy or unhappy. I think they will look ok, they do approach the chines on mine a bit as they push forward to the bow, but not to a degree that I think they look that funky. At this point I am just kind of trying to get them faired in as well as I can and get things flipping, aka moving on. Ripping them off sounds lousy tho. Now I am kind of anxiously awaiting a correction from Brian that I will then have to figure out if I need to fix or not. :)

Todd j

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Re: My Official build thread. 27 1/2’ GA
« Reply #332 on: September 19, 2019, 05:49:38 PM »
I did put a string at 19” from the chines at the stem and ran it. Ack through the rest of the marks.   BY my eye it more closely followed the chines without crowding them and them flaring away.   I used (or attempted to) a   batten as suggested.  It was impossible to get that thing to bend 10 directions at the same time.  I divided up the stations and shrunk the math and compared it to my original marks.  They were pretty close.  If Brian comes back with the same numbers, I think he will.  I will push the bow end away from the chines and rock on.  After I rebuild the spray rails

Brian.Dixon

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Re: My Official build thread. 27 1/2’ GA
« Reply #333 on: September 20, 2019, 06:23:44 AM »

Thanks for your patience guys ... probably won't get a chance to take a nice peaceful look into the CAD model until the morning....

Brian

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Jim_Hbar

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Re: My Official build thread. 27 1/2’ GA
« Reply #334 on: September 20, 2019, 01:01:54 PM »
I'm a little reluctant to comment here, having not built a GA, and therefore could be considered a bystander/non-combatant. ???

To my eye, virtually all Tolmans and GA's end up with aux. rail positions that aren't quite "in harmony" with the shear and chine in the final pictures, and all builds seem to have a struggle at this point. 

Why? I suspect that it is due to the fact that the shear tends to get "customized", and the chine location has a bit of float to it's position.  Also, the water-line and bottom paint come into play with the esthetics.

So, attempting to define an exact location in the plans that will please everyone, will likely prove to be an exercise in futility.:o

Brian.Dixon

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Re: My Official build thread. 27 1/2’ GA
« Reply #335 on: September 20, 2019, 04:26:45 PM »
I'm a little reluctant to comment here, having not built a GA, and therefore could be considered a bystander/non-combatant. ???

To my eye, virtually all Tolmans and GA's end up with aux. rail positions that aren't quite "in harmony" with the shear and chine in the final pictures, and all builds seem to have a struggle at this point. 

Why? I suspect that it is due to the fact that the shear tends to get "customized", and the chine location has a bit of float to it's position.  Also, the water-line and bottom paint come into play with the esthetics.

So, attempting to define an exact location in the plans that will please everyone, will likely prove to be an exercise in futility.:o

Even I don't like my original spray rail locations ... now preferring some up-sweep towards the stern.  The problem with spray rails that follow the chine (the most common example on the water) is that when the boat's floating level, the spray rails have a downward slope towards the stern that makes the boat look like it's sitting stern low when it's not. 

Brian

The Great Alaskan - Professional performance - Easy to build! - https://www.glacierboats.com  ><((((?> ... ><((((?> ... ><((((?> ... ><((((?>

json

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Re: My Official build thread. 27 1/2’ GA
« Reply #336 on: September 20, 2019, 04:51:23 PM »
I measured my installation of them, and am about an inch and a half less distance between the chine and the spray rail at the bow perpendicular to the chine vs about 60-80" aft of the bow, so they do curve back (at least relatively) towards the chine. I see what you are talking about Todd, and looking at 19" measured from the chine up the bow stem seems like it's more harmonious with the rest of the spray rail. That said, I think it will look sort of interesting and unique, so I think I will probably keep them there regardless of what Brian's CAD model says (thanks for looking that up Brian) especially since the alternative sounds really really painful. A paint job on an old p51 comes to mind...
« Last Edit: September 20, 2019, 05:36:11 PM by json »

Todd j

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Re: My Official build thread. 27 1/2’ GA
« Reply #337 on: September 20, 2019, 07:45:39 PM »
That is sexy!   I like the top pic too.  The bottom attachment was a oops
« Last Edit: September 20, 2019, 07:47:02 PM by Todd j »

Todd j

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Re: My Official build thread. 27 1/2’ GA
« Reply #338 on: September 20, 2019, 07:49:01 PM »
Brian.  I will do the banana spray rail.  Bow at 19” below chine with a roll of the dice.  How about 1 1-4” taper from the last 60” station to the stern.  What’s your .02?

Brian.Dixon

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Re: My Official build thread. 27 1/2’ GA
« Reply #339 on: September 21, 2019, 06:54:53 AM »
Brian.  I will do the banana spray rail.  Bow at 19” below chine with a roll of the dice.  How about 1 1-4” taper from the last 60” station to the stern.  What’s your .02?

I'm looking into the CAD stuff now ... it's tricky because when you build the boat, you measure along the surface and the change in flare along the sides makes the measurements inconsistent ... it's trigonometry.  You want a visually-correct line (side view) on a surface that's continuously changing.  I do like the higher sweep upward towards the bow, and I do like the 1-1/4 inch upward sweep at the stern.  I agree that this is the best looking spray rail and will make the 'looks' more forgiving of different boat loadings.

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Brian.Dixon

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Re: My Official build thread. 27 1/2’ GA
« Reply #340 on: September 21, 2019, 08:09:31 AM »

PROPOSAL - How do you like the spray rail line below?  I raised it up towards the bow and also at the stern .... I think the amount at the bow looks sporty?  Feedback welcome ... I want to update the plans and add a Sheet 012Alt that has a 'smile' or 'banana' splashrail.  The amount raised at the stern is 1-1/4", which I agree is just right.

Let me know what you guys think ... if it's cool, then I'll slice up the 3D CAD model with it and measure the offsets... and create the new drawing.

The Great Alaskan - Professional performance - Easy to build! - https://www.glacierboats.com  ><((((?> ... ><((((?> ... ><((((?> ... ><((((?>

Todd j

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Re: My Official build thread. 27 1/2’ GA
« Reply #341 on: September 21, 2019, 09:00:11 AM »
I’m in.  Looks delicious. I agree it’s difficult on the boat.  But easy in 2D.  The CAD pics in red above.  Can you give a brief explanation of each pic.  The red on red is hard for me to see what I’m looking at

Brian.Dixon

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Re: My Official build thread. 27 1/2’ GA
« Reply #342 on: September 21, 2019, 09:18:48 AM »
Sorry about the red on red.  It's the outer surface of the hull itself and all surfaces are on the same CAD layer ... There is one blue main stringer and the bow stem (also blue) in the pictures as well.

The reason for posting the pics is to show the curves from the side, but how they are different on the actual hull ... because the side flare varies continuously.

bd

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Todd j

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Re: My Official build thread. 27 1/2’ GA
« Reply #343 on: September 21, 2019, 09:39:14 AM »
Curios?   What number did you assign to the bow end from the chines?

Jim_Hbar

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Re: My Official build thread. 27 1/2’ GA
« Reply #344 on: September 21, 2019, 12:48:04 PM »
Personally, I prefer the shape of the "red on red" of the two examples shown.

To my eye, the rail can't be "more curved" than the shear - ie: it shouldn't converge on the sheer as the rail approaches the bow and stern.  But you are also fighting the increasing flare as you approach the bow, which is creating a bit of an optical illusion in the 2d sideview....

PS.  json - I believe that is a P40 - P51's had their air intake scoop for the radiator near the rear of the wing, the stance of the main gear was wider, and folded towards the center, not back.