Transverse frame calculation

Yes quite.

It's just that in BS designs everything by gut feel.

It's seems to be Brent's gut feeling that his design should be scalable to 60 feet. Got help the poor sod that takes it to sea. And I've offered to do the analysis for Brent as to it's failure pressure load.

 

"We"? I haven't heard or read that anywhere in this thread - only from you!
I think most of us don't really care about our clients wealth - we care about their safety! So should you!

 

Originally Posted by Brent Swain
Again we hear the elitist rant."Only the rich should be allowed to go cruising. Keep the riffraff under the bridge." Makes an egalitarian guy like me wanna be abrasive to such *******s. Freeing the rifraf give me a huge sense of accomplishment

LOL! I was waiting for this. Brent's favourite of the snake oils. Brent, do you know how right you are? Myself, Lyndon, Ad Hoc, DSkira, Apex, Bearflag, and all of the rest are millionaires, who don't want scum from the street dirtying our waters. When I'm not sitting in my chaise lounge at the shipyards counting my money, or on the phone with Ottawa, asking them to stop the filth from anchoring in our harbours, I'm out trying to fleece innocent first-time boatbuilders, because they are all so gullible, you know. Though my address has an apartment-like number beside the street number, it is really because I bought this skyscraper to bolster my income. It really pisses me off that the guy next door has 5 more floors than I do, though. I figure if I sell it off, I could almost afford to have you pull a hull together for me though. You wouldn't know poor if it bit you in the ***, Brent.

What's that, Brent? I still can't hear you. This ignore thing may cause me some confusion, but it sure is peaceful. Was A-hole the best he came up with or is there something I should know about my mother?

My apologies to others, my last few posts are taking this discussion sideways.

 

Build speed

Well Mike I guess I can chime in here on build speed .
When it come to building the hull ,transom, decks and cabin on an origami boat, it would be tough to beat when it comes to speed and simpicity. In comparison the 31'Robers vs Brents 31' , Cost wise materials about the same, With the time it is taking me to build frames I will have 50 to 60 hours in them. In that amount of time I could have Brents hull pulled together,transom , decks and cabin installed. As far as Keel or keels, skeg, rudder, detailed and fit out about the same .
So If a guy or gal was only building part time that is a pretty good jump start. At what I am figuring and trying to keep track of the Roberts will take about 3 weeks longer, 120 hours give or take. By the time the boat is finished that 120 hours doesn't seem like a lot to me but I quess it depends on how you look at it.
Tom

 

Fair comment, Tom! I guess it's too early to ask about time differences in fitting out the interior? I'm thinking that that should balance things out a bit. lol you must be scribing in your sleep! I apologize in advance for being unable to make further responses today, but I'm going sailing on a big a-hole yacht!

 

It is BS! And it shows your inability even at such level..............

The rest of your drivel is really not worth another thought.

Go, send your blue eyed customers to hell in your scrap yard junks and feel fine.

I hope this thread has scared away as many of them as possible, and I hope it will keep this function in future. There are too many here to quote this thread whenever you dish out your nonsense again, to let you escape as you did in the past.

BS
You should have listened to the generously given advice and offers to improve your faulty and dangerous sketches (they never ripened to plans).
Instead, you tried to discredit almost all of the professional designers, NA´s, engineers, welders, builders, homebuilders and not to forget the skilled amateurs which contradicted your statements in several dozens of threads, when your **** came up.

The demolition derby, which clearly was on my financial risk only, (even that you tried to misinterpret in your fact faker mentality) is not a valid offer any longer.
I neither waste my time with proven ******, nor my money. (the latter was not in a real risk)

As a last sidenote:

I am not aware of one critical member here being a "competitor" to your sort of floating devices, amongst those who contradicted to your dumb rants.
Therefore you cannot win with your argument that "we" are (in opposition to you) mainly interested in ripping your prospective clients off. But you are!
None of us is in your market segment (thanks god).

Go sailing, 12 month a year would be better than only 11.............
...and stay away from boatbuilding because you have NO clue about it!

Richard

 

Mike
I don't think the interior fitout would be much diferent. A lot there would depend if you have plans for the interior and follow them or if you have your own ideas and figure them out as you go.

Tom

 

http://en.wikipedia.org/wiki/De_Havilland_Comet and the Comet disasters of 1954.

(Oh but they were aluminium, not the magical steel.)

 

Nice sheer line. You have an eye for that. I once considered a full length keel for my 36. The strengths is attractive, but in steel that leaves you an extra 400 lbs of steel in the aft end of a boat , where you least need extra weight . It is common knowledge that the way to stop hobby horsing is to keep the ends light ,It also creates a deep void , under the engine which is very inaccessible for maintenance , not a problem for wooden boats which have the area sold wood, but a major headache for steel, something your mathematical calculations wont tell you. You cant have the area used as tankage without adding a huge amount more weight to the stern.
Again, putting wooden boat building practices in steel, where the material and it's priorities are entirely different, produces an inferior product..
The deadrise is excessive, a slow departure from the plank on edge theory that preceeded these types of hulls. It means a very tippy, tender hull shape incapable of carrying any adequate amount of sail when beating off a lee shore. The bottom of that deadrise is all buoyancy, with slack bilges, which will do nothing to offset it.
In that era this was compensated for by a stubby short gaff rig, and a long fragile bowsprit which wouldn't stand a chance in the t-boning of anything, as has been suggested..
The deep forefoot promises a heavy weather helm.
So how many of these have been built? Hundreds. I see my boats in many BC anchorages , which is why some have commented they are some of the most popular boats on the BC coast. Haven't seen any of Danny's, for obvious reasons . People prefer the benefits of what has been learned since the 30's..
It comes as no surprise that Danny's ideal boat is a throwback, which is a clinging white fisted grip to the technology of the thirties, suggesting nothing useful has been learned about hull shape since then. In that era crossing an ocean in anything but a huge ship was considered a daredevil stunt. His clinging to the past is clearly demonstrated by his criticism of anything innovative or modern, or recognising we are dealing with a different material than wood. . Modern boats with modern hull shapes will cross more miles in a couple of months that the boats Danny designs would have crossed in a lifetime. They abandoned such shapes for good reason, as offshore experience became more common.
The inboard rudder serves no useful advantage over an outboard rudder except to make self steering and inside steering far more complex , expensive and fragile than it would be for an outboard rudder. If course in Danny's era self steering vanes had not been invented yet, and it was considered heroic to sit in an open cockpit in a gale at sea. Now it is considered dense..

 

Well well.. hear the expert..
Why not tell the real stability data of your boats

 

Before you can comment you need to see that stability curve. Remember the stability curve ? Something you don't have for your designs but like to say you derived from the hull lines you also lied about. Compounded deception against an open honest design MO.

Daniel posted the lines to show people what the lines consist of are and usefully illustrate that they are the starting point of a design or at least should be. But you lied about that as well claiming you started with lines.

Hobby horsing depends on a lot more than the weight in the ends.
Why would a deep forefoot produce weather helm? Its not the forefoot present or not its the sail effort relative to the hydrodynamic center of balance.

Some people.....
Some people commented that the world would end in the year 2000 does that make the information valuable

Now how about those phenominally strong curves that replace transverse frames ???? I'd like to hear you on that rather than wild geese.

 

My answer is showing the calculations

1-Volume Moment and center of Buoyancy Write or erase only on the shaded area 18108/000 0.258 2.622

Station Simpson Fonction Arm Fonction Moment Simpson Fonction Area Moment
0 0.00 1 0.00 0 0.00 0.00 1 0.00 0.00 0.00 0
1 14.96 4 59.86 1 59.86 165.19 4 660.74 58.00 63.00 1
2 38.96 2 77.92 2 155.83 445.74 2 891.48 209.00 233.00 2
3 59.60 4 238.39 3 715.18 629.28 4 2,517.12 440.00 473.00 3
4 69.40 2 138.80 4 555.22 700.07 2 1,400.15 709.00 740.00 4
5 67.34 4 269.35 5 1,346.76 702.70 4 2,810.78 970.00 1,008.00 5
6 56.24 2 112.49 6 674.93 568.97 2 1,137.95 1,188.00 1,225.00 6
7 40.25 4 160.99 7 1,126.94 416.90 4 1,667.59 1,344.00 1,384.00 7
8 20.12 2 40.25 8 321.98 249.09 2 498.18 1,422.00 1,479.00 8
9 6.97 4 27.86 9 250.78 62.93 4 251.71 1,449.00 1,503.00 9
10 0.00 1 0.00 10 0.00 0.00 1 0.00 1,449.00 1,503.00 10
11 (373.84) 0 0.00 11 0.00 (3,940.87) 0 0.00 11
12 0.00 0 0.00 12 0.00 0.00 0 0.00 12
13 0.00 0 0.00 13 0.00 0.00 0 0.00 13
14 0.00 0 0.00 14 0.00 0.00 0 0.00 14
Sum 1,125.91 5,207.47 11,835.71
Co. Space cm 7.62 10.00 76.2 Station 1/2 ordinates
x2 2 0 0.00
1/3 3 1 3.74
Volume cm3 5,719.63 Scale3 1728 2 9.74
LCB cm 35.24 Scale2 144 10 100 3 14.90
VCB from baseline cm 10.51 Scale 12 4 17.35
Lbs 21,793.17 2.205 Coef.curve of volume 4 5 16.83
Cuft 340.52 64 6 14.06
Long Ton 9.73 2240 7 10.06
Dwl meter 9.14 100 8 5.03
Dwl Feet 30.00 3.281 PPA to ST0 in cm. 9.500 9 1.74
Dwl in cm 76.20 0.01 PPA to ST0 in m. 1.14 10 0.00
Lcb from St. #0 m. 4.23 0.300 LCB from PPA m. 5.37 11 (93.46)
PC 0.54 10,576.86 Block Coef 0.30 12 0.00
Displacement dm3 9,883.53 1000 VCB from Dwl in m. 0.41
Full Beam Dwl cm 19.20 0 Base line to DWL in m. 1.68 19,019.52
Draft hull cm 13.00 0.027004 Base line to CB in m. 1.26 10.51
Midship Sec. coef 0.54 249.6 Base line 13.97
Base line integrator less base line 0.00 Base line integrator 13.97
2-Area of Waterline, Inertia and Metacenter 18108/000
Scaled
Station 1/2 width dm Simpson Fonction Arm Fonction Cube Simpson Fonction 1/2 width dm
0 0.00 1 0.00 0 0.00 0.00 1 0.00 0.00
1 8.16 4 32.64 1 32.64 543.34 4 2,173.35 0.68
2 11.40 2 22.80 2 45.60 1,481.54 2 2,963.09 0.95
3 12.72 4 50.88 3 152.64 2,058.08 4 8,232.30 1.06
4 13.20 2 26.40 4 105.60 2,299.97 2 4,599.94 1.10
5 12.84 4 51.36 5 256.80 2,116.87 4 8,467.50 1.07
6 11.52 2 23.04 6 138.24 1,528.82 2 3,057.65 0.96
7 9.36 4 37.44 7 262.08 820.03 4 3,280.10 0.78
8 6.48 2 12.96 8 103.68 272.10 2 544.20 0.54
9 3.00 4 12.00 9 108.00 27.00 4 108.00 0.25
10 0.00 1 0.00 10 0.00 0.00 1 0.00 0.00
11 0.00 0 0.00 11 0.00 0.00 0 0.00
12 0.00 0 0.00 12 0.00 0.00 0 0.00
13 0.00 0 0.00 13 0.00 0.00 0 0.00
14 0.00 0 0.00 14 0.00 0.00 0 0.00
Sum 269.52 1,205.28 33,426.12

Co. Space dm 9.14 Full Scale Girth around the waterline in dm
Co. Space 1/3 3.05 3 Planking area around waterline in dm2 0.00
x2 2.00 2 Inside planking waterline line area dm2 1,642.99
1/3 3.00 3 Total waterline area 1,642.99
Area dm2 1,642.99
Center of Area from St.#0 in m. 4.09 40.89
Inertia 67,921.88 0.69
Metacenter dm BM 6.87 10 Metacenter hight from base line in m. 1.95
Metacenter feet BM 2.255 3.281
Waterline area feet2 176.85 10.764 30
Waterline area m2 16.43 57.3
Waterline coef 0.70 2,348.179 2.205
Lbs per inch of im. 920.19 0.254
Beam LWL in feet 8.662 0.305
Moment to alter trim 0.35
1" in foot-pound 1,263.80 1.41 Number of station 10
GM in Ft. 2.00 0.44
3-Wetted Area and Planking displacement 18108/000

Wetted area
Station 1/2 Girths dm Simpson Fonction
0 0.00 1 0.00
1 0.79 4 3.16
2 1.22 2 2.44
3 1.48 4 5.92
4 1.62 2 3.24
5 1.58 4 6.32
6 1.45 2 2.90
7 1.24 4 4.96
8 0.95 2 1.90
9 0.57 4 2.28
10 0.00 1 0.00
11 0 0.00
12 0 0.00
13 0 0.00
14 0 0.00
Sum 10.90 33.12

Co Space dm 0.762 Scale3 1728
Area full size dm2 2,422.79 Scale2 144
Bilge Factor 1.0356 Scale 12
Wetted area full size dm2 2,509.05 100 2
Planking thikness dm 0.254
Displ. planking full size dm3 0.00 10 3
Wetted area full size m2 25.09 10.764 0
Appendices full size dm3
ballast full size dm3 0.00
Wetted area appendices and ballast m2
Wetted area rudder m2 1.16
Total wetted area m2 26.25 Thickness rudder inches
Total displacement planking appendices and ballast dm3 0.00 Thickness rudder dm 0.00
Displacement rudder in dm3 0.00
Out board rudder thickness recommendation 1 7/8


4-Ballast 18108/000
Area Moment
Station 1/2 Area cm Simpson Fonction Arm Fonction From BL cm Fonction
0 1 0.00 0 0.00 0.00
1 4 0.00 1 0.00 0.00
2 2 0.00 2 0.00 0.00
3 4 0.00 3 0.00 0.00
4 2 0.00 4 0.00 0.00
5 4 0.00 5 0.00 0.00
6 1 0.00 6 0.00 0.00
7 0 0.00 7 0.00 0.00
8 0 0.00 8 0.00 0.00
0 0 0.00 9 0.00 0.00
0 0 0.00 10 0.00 0.00
0 0 0.00 11 0.00 0.00
0 0 0.00 12 0.00 0.00
0 0 0.00 13 0.00 0.00
0 0 0.00 14 0.00 0.00
Sum 0.00 0.00 0 0.00 0.00

Co. Space cm 10.00 0
x2 2 VC of gravity from base line in cm ERR
1/3 3
Volume cm3 0.00 Scale3 1728 Weight cement within rebar in Kg 0.00
LCB in cm ERR Scale2 144 Volume dm3 left for cement 0.00
Scale 12 Volume Ft3 left for cement 0.00
Displ. dm3 full scale 0.00 0.00 Weight rebar 1/2" by 1' in Kg
Weight Lead kg 0.00 11.2 With 6% antimony Length of rebars in feet
Weight Iron kg 0.00 7.7 Iron Number of rebars
Weight cement kg 0.00 2.3 Portland Cement Total weight of rebars in Kg 0.00
Weight cement / iron kg 0.00 Total weight of rebars in Lbs 0.00
Weight Lead lbs 0.00 2.205 Specific weight ERR
Weight Iron Lbs 0.00 10 Volume dm3 of rebar 0.00
Weight cement Lbs 0.00 1000
Weight cement / iron Lbs 0.00
Displacement Ft3 0.00 35.315


5-Ballast cement/rebar 18108/000
Area Distances Trapezoidal
Station 1/2 Area dm Simpson Fonction Arm Fonction From Station 0 Moment 1/2 Area dm
0 0.070 1 0.07 0 0.00 0.04
1 0.101 4 0.40 1 0.40 0.12
2 0.115 2 0.23 2 0.46 0.19
3 0.122 4 0.49 3 1.46 0.08
4 0.185 2 0.37 4 1.48 0.05
5 0.101 4 0.40 5 2.02 0.00
6 0.080 2 0.16 6 0.96
7 0.061 4 0.24 7 1.71
8 0.053 2 0.11 8 0.84
9 0.018 4 0.07 9 0.64
10 0.000 1 0.00 10 0.00
0 0 0.00 11 0.00
0 0 0.00 12 0.00
0 0 0.00 13 0.00
0 0 0.00 14 0.00
Sum 0.91 2.55 9.9887 0.00 0.00 0.47
Displacement dm3 full scale trapezoidal 614.25
Co. Space dm 0.38 10.00 3.8
x2 2 LCG From Station 0 scaled in dm 0.00
1/3 3
Volume dm3 0.65 Scale3 1728 Weight cement within rebar in Kg 2,110.39
LCB in dm 1.49 Scale2 144 Volume dm3 left for cement 879.33
Number of station 4.00 Scale 12 Volume Ft3 left for cement 31.05
Displ. dm3 full scale 1,115.43 Weight rebar 1/2 by 1' in Kg 0.303
Weight Lead kg 12,492.86 11.2 With 6% antimony Length of rebars in feet 20
Weight Iron kg 8,588.84 7.7 Iron Number of rebars 300
Weight cement kg 2,677.04 2.4 Portland cement Total weight of rebars in Kg 1,818.00
Weight cement rebar kg 3,928.39 100 Total weight of rebars in Lbs 4,008.69
Weight Lead lbs 27,546.77 2.205 Specific weight 3.52
Weight Iron Lbs 18,938.40 10 Volume dm3 of rebar 236.10
Weight cement Lbs 5,902.88 1000
Weight cement rebar Lbs 9,911.57 1.52
Displacement Ft3 39.39 35.315
PC ballast 1.15 0.56
6-Ballast concrete / steel inside 18108/000 0.258 2.622

Station Simpson Fonction Arm Fonction Moment Simpson Fonction Area Moment
0 0.00 1 0.00 0 0.00 0.00 1 0.00 0
1 0.00 4 0.00 1 0.00 0.00 4 0.00 1
2 0.00 2 0.00 2 0.00 0.00 2 0.00 2
3 0.00 4 0.00 3 0.00 0.00 4 0.00 3
4 0.00 2 0.00 4 0.00 0.00 2 0.00 4
5 0.00 4 0.00 5 0.00 0.00 4 0.00 5
6 0.00 2 0.00 6 0.00 0.00 2 0.00 6
7 0.00 4 0.00 7 0.00 0.00 4 0.00 7
8 0.00 1 0.00 8 0.00 0.00 1 0.00 8
9 0.00 0 0.00 9 0.00 0.00 0 0.00 9
10 0.00 0 0.00 10 0.00 0.00 0 0.00 10
0 0.00 0 0.00 0 0.00 0.00 0 0.00 11
0 0.00 0 0.00 0 0.00 0.00 0 0.00 12
Sum 0.00 0.00 0.00 0.00
Co. Space cm 0 Station 1/2 ordinates
x2 2 0 ERR
1/3 3 1 ERR 1170
Volume cm3 0.00 Scale3 1728 2 ERR
LCB in cm. ERR Scale2 144 3 ERR
VCB from baseline cm ERR Scale 12 4 ERR
Displacement dm3 0.00 2.205 3.5 Coef.curve of volume 5 ERR
Ballast Portland (3.2) Kg 0.00 64 2.2 6 ERR
Ballast Portland /rebar Kg 0.00 2240 7.7 7 ERR
Ballast iron (7.2) Kg 0.00 100 11.3 Volume Ft3 left for cement 0.00 8 ERR
Ballast lead (11.3) Kg 0.00 3.281 0.01 Volume dm3 left for concrete 0.00 9 ERR
Ballast cement (2.2) Lbs 0.00 0.013 Weight of concrete in Kg. 0.00 10 ERR
Balast cement/ rebar Lbs 0.00 0.000002 Weight rebar 1/2 by 1' in Kg 0.303 11 ERR
Ballast iron (7.2) Lbs 0.00 1000 10 Length of rebars in feet 12 ERR
Ballast lead (11.3) Lbs 0.00 ERR 100 Number of rebars
Base line to CB in m. 1.26 ERR Total weight of steel in Kg 0.00
VCB from Dwl m. ERR ERR Total weight of steel Lbs 0.00
Displacement/ ballast 0.00% Total specific weight ERR
CP ERR 0.00 Volume dm3 of rebar 0.00
Volume floors in dm3 0.00 0.00 Floor thickness in dm
Volume left for ballast in dm3 0.00 Multiple for floors
7-Planking 18108/000
Planking Moment dm Half girth
Station 1/2 Girths dm Simpson Fonction Arm Fonction From base line Fonction dm
0 0.00 1 0.00 0 0.00 0.00 0.00 0.00 0
1 0.70 4 2.80 1 2.80 1.90 1.33 0.35 1
2 1.25 2 2.50 2 5.00 1.65 2.06 0.63 2
3 1.44 4 5.76 3 17.28 1.52 2.19 0.72 3
4 1.62 2 3.24 4 12.96 1.44 2.33 0.81 4
5 1.80 4 7.20 5 36.00 1.32 2.38 0.90 5
6 2.00 2 4.00 6 24.00 1.25 2.50 1.00 6
7 2.10 4 8.40 7 58.80 1.15 2.42 1.05 7
8 2.22 2 4.44 8 35.52 1.10 2.44 1.11 8
9 2.27 4 9.08 9 81.72 1.07 2.43 1.14 9
10 2.32 2 4.64 10 46.40 1.05 2.44 1.16 10
11 2.35 4 9.40 11 103.40 1.05 2.47 1.18 11
12 2.32 2 4.64 12 55.68 1.07 2.48 1.16 12
13 2.32 4 9.28 13 120.64 1.10 2.55 1.16 13
14 2.29 2 4.58 14 64.12 1.15 2.67 1.16 14
15 2.25 4 9.00 15 135.00 1.22 2.75 1.13 15
16 2.17 2 4.34 16 69.44 1.27 2.76 1.09 16
17 2.07 4 8.28 17 140.76 1.34 2.77 1.04 17
18 1.95 2 3.90 18 70.20 1.45 2.83 0.97 18
19 1.93 4 7.72 19 146.68 1.54 2.97 0.84 19
20 1.67 2 3.34 20 66.80 1.65 2.76 0.75 20
21 1.50 4 6.00 21 126.00 1.79 2.69 0.00 21
22 0.00 1 0.00 22 0.00 0.00 0.00 0.00 22
40.54 122.54 1,419.20 52.20

Scale3 1728 2 Section frames dm 0.762 0.047 Lcg full scale M. from PPA 5.30
Scale2 144 1000 Density frames 7.80 Number of station 22
Scale 12 540.7152 Weight of frames 271.80 100.58 VCG from base line in M. 1.55
144.00 Planking m3 0.22 3.281 Planking thickness inches 3/16
Co. Space dm 0.381 1728 Frames m3 0.03 35.315 Planking square inches 71,945.28
Area dm2 full scale 4,641.58 0.254 3 Planking sq ft 499.62 Planking inches3 13,489.74
Planking thikness 0.048 100 1.29 Planking coef 0.96 4,828.03 Planking board feet 93.68
Planking density 7.80 22 31.13 Bilge factor 1.0356 Frames feet3 1.23
Weight plank 1,723.33 10.764 32.23 Length frames dm 972.96 Frames inches3 2,126.43
L..Center. of gravity 4.41 10 Multiple for frames 1 Frames board feet 14.77
8-Ceiling 18108/000
Ceiling Moment dm Half girth
Station 1/2 Girths dm Simpson Fonction Arm Fonction From base line dm
0 1 0.00 0 0.00 0.00 0.00 0
1 4 0.00 1 0.00 0.00 0.00 1
2 2 0.00 2 0.00 0.00 0.00 2
3 4 0.00 3 0.00 0.00 0.00 3
4 2 0.00 4 0.00 0.00 0.00 4
5 4 0.00 5 0.00 0.00 0.00 5
6 1 0.00 6 0.00 0.00 0.00 6
7 4 0.00 7 0.00 0.00 0.00 7
8 2 0.00 8 0.00 0.00 0.00 8
9 4 0.00 9 0.00 0.00 0.00 9
10 2 0.00 10 0.00 0.00 0.00 10
11 4 0.00 11 0.00 0.00 0.00 11
12 1 0.00 12 0.00 0.00 0.00 12
13 0 0.00 0 0.00 0.00 0.00 13
14 0 0.00 0 0.00 0.00 0.00 14
15 0 0.00 0 0.00 0.00 0.00 15
16 0 0.00 0 0.00 0.00 0.00 16
0.00 0.00 0.00 0.00

Co. Space dm 0.762 Scale3 1728 2 3
Area dm2 full scale 0.00 Scale2 144 1000 ERR
Ceiling thickness dm Scale 12
Ceiling density 0.00
Weight ceiling 0.00 100 0.00
L..Center. of gravity ERR 0 Lcg dm scaled from St0 ERR
Ceiling m3 0.00 10.764
Ceiling sq ft 0.00 10
Ceiling coef ERR 0.00 Vert. center of gravity from base line in M. ERR
Bilge factor 1.0356 3.281
0.254 Number of station
0.00




9-Datas 18108/000

Imperial Ft. Metric M. Measurement
in Inches
Length overall 34.000 10.370 34.00 0.305 3.281
Length on deck 34.000 10.370 34.00 3.00
Length @ Dwl 30.000 9.150 30.00 0.454 2.205
Beam extreme 10.000 3.050 10.00 0.01 2.00
Beam @ Dwl 8.688 2.650 8.69 0.0270 0.305
Draft @ Dwl 5.250 1.601 5.25 12 2,240.00
Draft Light 0.000 0.000 9.73
Draft fully loaded 0.000 0.000 64.00
Depth moulded 7.375 2.249 7.38 1.50
Lowest point freeboard 3.188 0.972 3.19 10.00
Displacement 3.14
Displacement Light 0.00 180.00
Displacement Loaded 0.00 32.20
Displacement at Dwl. 21,793.17 9,883.53
Displacement inside planking 21,793.17 9,883.53 First equation 6.28 / period of roll y 2 7.29
Outside ballast 0.00 0.00 Period or roll in second 2.70 10.94
Inside ballast 8,662.11 3,928.39 GM in M. 0.61 0.17
Total ballast 8,662.11 3,928.39 Full beam in yard 3.33 0.01
D/L 360.34 Roll Acceleration G,s 0.059
PC 0.54 Sine of 20 degree 0.342
BC 0.30 Righting arm @ 20 degree in feet 0.68
Mid Section coef 0.54 Wind Pressure Coefficient 1.33
Dwl coef 0.70
Length / Beam 3.40 3.40 Center Sail Area From WL meter ERR
Dwl / Beam Dwl 3.45 3.45 Center Lateral Area From WL meter ERR
Displ./ ballast 39.75% 39.75% Moment Ft/Lbs to produce 1o of heel 760.58 0.01745
Sail Area / Displ. 13.22 Angle of heel in degree 1.1 0.09
GM feet and meter 2.00 0.61 Weight in Lbs 170.00 0.45
Lbs per inch imm. 920.19 Imperial Metric Distance from centerline ft. 5.00 0.093
Sail Area sqft 587.7 587.7 54.6 850.00
Dellenbaught degree 14.68 57.30 0.61 Weight of sail in Kg 24.01 10.764
Heeling arm in feet 19.000 54.6 Capsize coef 1.50
Wetted area m2 26.25 43,586.35 Sail area/wetted area 2.08 Disp. Cuft y 0.666 44.44
Wetted area sqft 282.56 Displacement cuft 340.52 Displacement cuft3 6.68
10-Lateral area 18108/000


Moment from
Station Depth in dm Simpson Fonction BL in dm
0 1 0.00 0 0.00 0.00
1 4 0.00 1 0.00 0.00
2 2 0.00 2 0.00 0.00
3 4 0.00 3 0.00 0.00
4 2 0.00 4 0.00 0.00
5 4 0.00 5 0.00 0.00
6 1 0.00 6 0.00 0.00
7 0 0.00 7 0.00 0.00
8 0 0.00 8 0.00 0.00
9 0 0.00 9 0.00 0.00
10 0 0.00 10 0.00 0.00
11 0 0.00 11 0.00 0.00
12 0 0.00 12 0.00 0.00
13 0 0.00 13 0.00 0.00
14 0 0.00 14 0.00 0.00
Sum 0.00 0.00 0.00 0.00

Co Space dm Scale3 1728 3 11.5
Lateral area dm2 0.00 Scale2 144 100 0
Lateral area m2 0.00 Scale 12 10
Lc of lateral area from St 0 ERR
Lc of lateral area from St0 in Ft. ERR 10 2
Lc of lateral area from St0 in M. ERR
Rudder area m2 0.580 ERR
Rudder area / lateral plane ratio ERR Out board rudder thickness recommendation
Sail area / lateral plane ratio ERR ERR See page 3 for definitive thickness
VC from BL in cm. ERR ERR Inches minimum 1 7/8
VC from WL in M. ERR 44.000 12.66 Dm minimum 0.47
Rudder area Ft2 6.24 3.476 10.764
0.254



11-Mast 18108/000
Expressed in Imperial

Main mast Mizzen mast

Righting m. at 30o 22,820.08 1,307,590.46 Righting m. at 30o 22,820.08
Constent 2.78 2.00 Constent 1.90
Half beam in feet 4.75 57.30 Half beam in feet 2.16
Main mast load 13,355.75 30.00 Mizzen mast load 20,073.22
Main mast load 1.34 10,000.00 Mizzen mast load 2.01
Panel trans inches 336.00 Panel trans inches
Panel longit. inches 300.00 Panel longit. inches
T squ /fourth power 11.29 T squ /fourth power 0.00
L squ fourth power 9.00 L squ fourth power 0.00
1 spreader
ITT 1 spreader 21.26 Spruce 6.78 2/3 spreader ITT 1 spreader 0.00
ITT 2/3 spreader 122.28 8.11 ITT 2/3 spreader 0.00
Masthead
ILL masthead 9.74 Spruce 4.00 7/8 ILL masthead 0.00
ILL 7/8 44.96 3.74 ILL 7/8 0.00
Mast diameter inches 5 ITT 1 spreader mast on deck Mast diameter inches 4 1/2
Boom diameter in inches 3 1/2 1.41 60% Boom diameter in inches
Gaff diameter in inches 3 ILL masthead mast on deck 0.50 Gaff diameter in inches
Standing rigging load 7,206.34 0.81 1.50 Standing rigging load 5,282.43
Shroud load 4,323.80 Shroud load 3,169.46
Legth of mast in dm 98.4 0.635 0.5715 Legth of mast in dm 38.4
Diameter of mast in dm 1.27 0.254 0.32661225 Diameter of mast in dm 1.143
Density of mast 0.45 0.40 1.026082645 Density of mast 0.5
Weight of mast in kg 56.09 3.1416 0 Weight of mast in kg 19.70
Legth of boom in dm 69.6 2 0 Legth of boom in dm 20
Diameter of boom in dm 0.889 0.44 0 Diameter of boom in dm 0
Density of boom 0.45 0.20 0 Density of boom 0.4
Weight of boom in kg 19.44 0.62 0 Weight of boom in kg 0.00
Legth of gaff in dm 46.8 0.38 0 Legth of gaff in dm
Diameter of gaff in dm 0.762 0.15 Diameter of gaff in dm 0
Density of gaff 0.45 0.46 Density of gaff
Weight of gaff in kg 9.60 Weight of gaff in kg 0.00
12-Deck and Beams 18108/000

Station 1/2 beam dm Simpson Fonction Arm Fonction
0 0.70 1 0.70 0 0.00
1 0.80 4 3.20 1 3.20
2 0.90 2 1.80 2 3.60
3 0.63 4 2.52 3 7.56
4 0.72 2 1.44 4 5.76
5 0.78 4 3.12 5 15.60
6 1.18 2 2.36 6 14.16
7 1.22 4 4.88 7 34.16
8 1.24 2 2.48 8 19.84
9 0.72 4 2.88 9 25.92
10 0.73 2 1.46 10 14.60
11 0.72 4 2.88 11 31.68
12 0.70 2 1.40 12 16.80
13 0.67 4 2.68 13 34.84
14 0.63 2 1.26 14 17.64
15 0.58 4 2.32 15 34.80
16 1.06 2 2.12 16 33.92
17 0.97 4 3.88 17 65.96
18 0.85 1 0.85 18 15.30
19 0.71 0 0.00 19 0.00
20 0.54 0 0.00 20 0.00
21 0.33 0 0.00 21 0.00 No.of stations
22 0 0 0.00 22 0.00 Length of deck in M. 0.00
44.23 395.34 Length of deck scaled 0.00
Lcg in M 4.09
Co. Space dm 0.381 Scale3 Section beams dm 0.05 0.57 1728 Deck feet3 1.77
Area dm2 full scale 1,617.76 Scale2 Density beams 7.80 144 Deck inches3 3,060.40
Deck thikness dm 0.031 Scale Weight of beams 71.79 35.315 12 Deck board feet 21.25
Deck density 7.80 10.764 Deck m3 0.05 1728 2 Beams feet3 0.33
Weight Deck 391.17 100 Beams m3 0.01 144 3 Beams inches3 561.67
L..Center. of gravity 3.41 10 Deck area Ft2 174.14 Beam board feet 3.90
Length for beams in dm 335.52 25.13076
Multiple for beams 1
13-Specifications 18108/000
Length overall 34.000 Ft 10.37 M.
Length on deck 34.000 Ft 10.37 M. 0.305
Length @ Dwl 30.000 Ft 9.15 M. 0.454
Beam extreme 10.000 Ft 3.05 M. 3
Beam @ Dwl 8.688 Ft 2.65 M. 3.281
Draft @ Dwl 5.250 Ft 1.60 M. 2.205
Draft Light 0.000 Ft 0.00 M. 2240
Draft fully loaded 0.000 Ft 0.00 M.
Depth moulded 7.375 Ft 3.35 M
Lowest point freeboard 3.188 Ft 0.97 M.
Displacement Light 0.00 Lbs 0.00 Kg
Displacement Loaded 0.00 Lbs 0.00 Kg
Displacement at Dwl. 21,793.17 Lbs 9,883.53 Kg 64
Displacement Long Tons @ Dwl 9.73 Lt 9.88 Metric tonnes
Diplacement cubic feet 340.52 Ft3 1000
Lcb From Station #0 13.88 Ft 4.23 M. 10.764
Vcb From Dwl 1.361 Ft 0.41 M.
Length/Beam 3.40 3.40
P.C 0.54 0.54
B.C 0.30 0.30
Lbs Per Inch Immersion 920.192 Lbs
Kg Per 1dm of immersion 1,642.99 Kg
GM 2.00 Ft 0.61 M.
Period or roll 2.70 Second 2.70 Second
Transverse BM 2.255 Ft 0.69 M.
Moment To Change Trim 1" 1,263.797 Ft/Lbs
Moment to change trim 0.25dm 191.25 Dm/Kg
Wetted Area Feet2 282.560 Ft2 26.25 M2
Outside ballast 0.00 Lbs 0.00 Kg
Inside ballast 8,662.11 Lbs 3,928.39 Kg
Total ballast 8,662.11 Lbs 3,928.39 Kg
Ballast/Dwl Displacement 0.00% 0.00%
Displacement/Lwl 360.34 360.34
Lateral plane area 0.00 Ft2 0.00 M2
LC of lateral plane ERR Ft ERR M 18108/000
Waterline area 176.85 Ft2 16.43 M2
Waterline Coef. 0.70 0.70
Center Flotation From Station #0 13.42 Ft 4.09 M.
Sail area 587.71 Ft2 54.60 M2
Sail area / wetted area 2.08 2.08
Moment Ft/Lbs to produce 1o of heel 760.58
Dellenbaught degree 14.68 14.68
Wind Pressure Coef 1.33 1.33
Sail Area / Displ. 13.22 13.22
Rudder Area 6.24 Ft2 0.58 M2
Rudder area / lateral plane ratio ERR ERR
Sail area / lateral plane ratio ERR ERR
Capsize coef 1.50 1.50
Roll Acceleration G,s 0.06 0.06
Fuel 0.0 Us Gal. L. 0.264
Water 0.0 Us Gal. L.
Lub oil 0.0 Us Gal. L.
Gray water 0.0 Us Gal. L.
Black water 0.0 Us Gal. L.
Trim tanks 0.0 Us Gal. L.

Performances
Maximum speed Mph
Comsumption @ cruising speed Us Gal/h
Cruising speed Mph
Range N. Miles
Endurance in day power non stop power days
Endurance in day power 12 hours/day days
Endurance in day power 8 hours/day days
Engine
Main engine Beta 1505 36hp @ 3000 rpm
Transmission 2:01
Shaft
Proppeller 16X8

 

And the weight calculation:

Weight Distribution for drawing number 18108/000 Skira Yacht Design
For John Dugdill Esq. P.O.Box 614, Rockport, Maine 04856, USA
Full scale
Expressions in column 3 to 8 are in Kilog and Meter. Expressions in column 9 are in Lbs
2.205
1 2 3 4 5 6 7 8 9 10
LCG from Total Vcg from
Weight in Kg. PPA in M. Kg/M. weight Kg Base line in M Kg/M Item Lbs

Plating 1,723.00 5.30 9,131.90 1,723.00 1.55 2,670.65 Plating 3,799.22
CVK 794.00 4.08 3,239.52 2,517.00 0.48 381.12 CVK 1,750.77
Frames 271.81 5.30 1,440.59 2,788.81 1.55 421.31 Frames 599.34
Floors 193.00 5.56 1,073.08 2,981.81 0.69 133.17 Floors 425.57
Upper clamp solid rod 47.00 5.30 249.10 3,028.81 2.22 104.34 Upper clamp solid rod 103.64
Lower clamp solid rod 45.00 5.30 238.50 3,076.81 1.68 75.60 Lower clamp solid rod 0.00
Engine bed 32.80 2.52 82.66 3,106.61 1.20 39.36 Engine bed 72.32
Clamp pipe 53.30 5.34 284.62 3,159.91 2.76 147.11 Clamp pipe 117.53
Deck beams 71.79 4.09 293.62 3,231.70 2.76 198.14 Deck beams 158.30
Deck 404.00 4.09 1,652.36 3,635.70 2.76 1,115.04 Deck 890.82
Wood deck shething 19mm pine 153.69 4.09 628.59 3,789.39 2.76 424.18 Wood deck shething 338.89
Braquet beam frames 9.00 4.09 36.81 3,798.39 2.76 24.84 Braquet beam frames 19.85
Transom 48.25 0.28 13.32 3,846.64 2.40 115.80 Transom 106.39

Bulkhead # 4 T & G sheather 31.00 2.82 87.42 3,877.64 1.94 60.14 Bulkhead # 4 T & G sheather 68.36
Bulkhead # 4 61.60 2.82 173.71 3,939.24 1.94 119.50 Bulkhead # 4 135.83

Saloon seat base 15.39 6.72 103.42 3,954.63 1.44 22.16 Saloon seat base 33.93
Saloon seat fashia 13.95 6.96 97.09 3,968.58 1.30 18.14 Saloon seat fashia 30.76
Ceiling 137.28 5.40 741.31 4,105.86 1.92 263.58 Ceiling 302.70
Aft cabin berth 36.00 3.84 138.24 4,141.86 1.68 60.48 Aft cabin berth 79.38
Aft cabin hatch 15.00 4.32 64.80 4,156.86 3.06 45.90 Aft cabin hatch 33.08

Bulwark 109.00 4.09 445.81 4,265.86 2.88 313.92 Bulwark 240.35
Rail 39.00 4.09 159.51 4,304.86 2.92 113.88 Rail 86.00
Cockpit hatch 20.50 2.22 45.51 4,325.36 2.23 45.72 Cockpit hatch 45.20
Cokpit side 48.70 1.92 93.50 4,374.06 2.40 116.88 Cokpit side 107.38
Cockpit sole 36.00 1.92 69.12 4,410.06 2.23 80.28 Cockpit sole 79.38
Cockpit sole beams 0.00 4,410.06 0.00 Cockpit sole beams 0.00
Rudder post case 4.30 0.79 3.40 4,414.36 2.17 9.33 Rudder post case 9.48
Rudder 29.00 0.91 26.39 4,443.36 0.84 24.36 Rudder 63.95

Trunk cabin four side 74.46 5.58 415.49 4,517.82 2.76 205.51 Trunk cabin four side 164.18
Trunk cabin deck 40.00 5.34 213.60 4,557.82 3.06 122.40 Trunk cabin deck 88.20
Trunk cabin deck beams 9.00 5.34 48.06 4,566.82 3.00 27.00 Trunk cabin deck beams 19.85
Hatch deck saloon 15.00 4.32 64.80 4,581.82 3.06 45.90 Hatch deck saloon 33.08
Hatch head 15.00 8.38 125.64 4,596.82 2.94 44.10 Hatch head 33.08

Main mast 56.09 6.72 376.92 4,652.91 7.56 424.04 Main mast 123.68
Gaff 13.07 4.80 62.74 4,665.98 10.68 139.59 Gaff 28.82
Boom 19.44 3.12 60.65 4,685.42 3.36 65.32 Boom 42.87
Bowsprit 19.70 5.76 113.47 4,705.12 3.36 66.19 Bowsprit 43.44
Compression post 18.40 7.18 132.11 3,000.52 1.86 34.22 Compression post 147.20
Sails hoisted 23.75 5.40 128.25 4,747.27 6.41 152.24 Sails hoisted 52.37

Holding tank 8.60 9.00 77.40 4,755.87 1.44 12.38 Holding tank 18.96
Fuel tank 60.93 3.18 193.76 4,816.80 1.44 87.74 Fuel tank 134.35
Water tank 73.26 5.32 389.74 4,890.06 0.95 69.60 Water tank 161.54

Cabin sole 46.83 5.64 264.12 4,936.89 1.11 51.98 Cabin sole 103.26
Galley countertop 7.00 5.52 38.64 4,943.89 1.98 13.86 Galley countertop 15.44
Galley fashia 9.20 5.70 52.44 4,953.09 1.56 14.35 Galley fashia 20.29
Galley stove with gimbal 28.00 5.16 144.48 4,981.09 1.74 48.72 Galley stove with gimbal 61.74
Head countertop 5.64 8.28 46.70 4,986.73 1.98 11.17 Head countertop 12.44
Head fashia 12.00 8.28 99.36 4,998.73 1.62 19.44 Head fashia 26.46
Head 25.00 8.46 211.50 5,023.73 1.36 34.00 Head 55.13

Batteries 3/108AH 120.00 4.20 504.00 5,143.73 0.78 93.60 Batteries 264.60
Shaft and fittings 0.00 5,143.73 0.00 Shaft and fittings 0.00
Engine 170.00 2.46 418.20 5,313.73 1.74 295.80 Engine 374.85
Wire rope 3/8" 40.00 9.00 360.00 5,353.73 3.24 129.60 Wire rope 88.20
Windlass Wintech 47.00 9.00 423.00 5,400.73 3.24 152.28 Windlass 103.64
Anchor 45.00 10.44 469.80 5,445.73 3.36 151.20 Anchor 99.23
Interior ballast (ratio) 35.41% 3,500.00 5.52 19,320.00 8,945.73 0.55 1,925.00 Interior ballast (ratio) 7,717.50
Trim ballast 300.00 8.52 2,556.00 9,245.73 0.90 270.00 Trim ballast 661.50

Total 47,924.78 9,245.73 11,852.15 Total weight light ship 20,394.24
2.08 Total weight without ballast 11,916.01
96.53%
Displacement Light 9,245.73
Vertical center gravity from base line 1.28
Longitudinal center of gravity from PPA in M. 5.18
Difference light to displacement @ DWL in Kg 637.27 Kg per one dm of immersion 1,642.00

Displacement @ DWL 9,883.00

Cargo weight

Holding tank 120.00 9.00 1,080.00 9,365.73 1.44 172.80
Fuel density 0.85 126.00 3.18 400.68 9,491.73 1.44 181.44
Water 158.00 5.32 840.56 9,649.73 0.95 150.10
Crew in cockpit (2) 160.00 1.86 297.60 9,809.73 3.00 480.00
Crew seated inside (2) 160.00 6.84 1,094.40 9,969.73 1.74 278.40
Peoples effects cruising gear 100.00 4.20 420.00 9,909.73 1.44 144.00
Store food and cargo 100.00 5.76 576.00 10,009.73 1.37 137.00

Total 924.00 52,634.02 10,169.73 13,395.89

Displacement loaded in Kg 10,169.73
VCG loaded from base line in M. 1.32
LCG loaded from PPA in M. 5.18 -0 11/16 Minus indicate immersion in inches from DWL
Difference loaded to displacement @ DWL in Kg (286.73)

Black water tank 10% 0.00 0.00 0.00 9,245.73 0.00 0.00
Grey water tank 10% 47.28 9.00 425.52 9,293.01 1.44 68.08
Fuel Diesel 0.85 density 10% 12.60 3.18 40.07 9,305.61 1.44 18.14
Water 10% 15.80 5.32 84.06 9,321.41 0.95 15.01
Crew cruising maximum (2 p.) 160.00 1.86 297.60 9,481.41 3.00 480.00
Peoples effects cruising gear 100.00 4.20 420.00 9,581.41 1.44 144.00
Store 10% 10.00 5.76 57.60 9,591.41 1.37 13.70

Total 345.68 49,249.63 9,591.41 12,591.09

Displacement loaded 10% 9,591.41
VCG loaded 10% from base line in M. 1.31
LCG loaded 10% from PPA in M. 5.13
Difference loaded 10% to displacement @ DWL in Kg 291.59

Longitudinal Center of Buoyancy from PPA in M. 5.37
LCG light to LCB in Cm. (18.65) 96.53%
LCG loaded from LCB in Cm. (19.44) 96.38%
LCG loaded 10% from LCB in Cm. (23.52) 95.62%

Draft DWL in cm. 160.020
Draft DWL in inches 63.000
Metacenter hight from base line in M. 1.950 3.281
GM light in Meter 0.67 2.205
GM light in Feet 2.19 10
GM loaded in Meter 0.63 12.00%
GM Loaded in Feet 2.08 10.00%
GM Loaded 10% in Meter 0.64 0.394
GM Loaded 10% in Feet 2.09 100
GM average in Meter 0.65 3
GM average in Feet 2.12
2.54
Displacement light in Kg 9,245.73 15.00%
Displacement light in Lbs 20,386.83 12
Displ. fully commissioned in Kg 10,169.73
Disp. fully commissioned in Lbs 22,424.25
Displ. 10% commissioned in Kg 9,591.41
Displ. 10% commissioned in Lbs 21,149.06

Loaded WL from DWL in Cm. (1.75)
Loaded WL from DWL in Inches -0 11/16
Light WL from DWL in line Cm 3.88
Light WL from DWL in Inches 1 1/2

Draft loaded in feet 5.31
Draft loaded in meter 1.62
Draft light in feet 5.12
Draft light in meter 1.56

Max. load ex. fuel & water in Kg 520.00
Max. load ex. fuel & water in Lbs 1,146.60
Max.load with fuel and water in Kg 924.00
Max load with fuel and water in Lbs 2,037.42
Payload in Kg 200.00
Payload in Lbs 441.00

Maximum crew for day trip 6 80.00
Maximum crew for cruise 4

 

Window Microsoft Works 4

Sorry Brent I don't make comment without backing.
Could you do the same please, or just shut up.
Amateurs when they think they know are ennoying when they comment. Brent is a good exemple.
Why on earth they don't ask question?
When I had my back surgery, I didn't comment how to do it, I asked a lot of questions, listen, let the surgeaon open me up, and thanks God I feel good.
Same when I take my dear car to the mechanic, I don't tell him what to do, I listen and learn.
As for speed, I predict that Brent's two keel monster, must go at least 5 knots, and the windward hability must be quite louzy.
Talking speed on a displacement sailing yacht is ridiculus.
Why? because depend of: wind, sea, hability of the crew, length of the traveling, quality of the underwater, season and so on.
LeghII which was considered slow, went pretty fast, as Spray, as Josua, as Suhali, as countless of heavy boat, but with brillant skipper. (Of course Brent do not know these boat, I should send him the particulars)

Sorry Peers, I use Window Microsoft Works 4.
If somebody want I can send by snake mail all the calculations, it will be more comprehensible.


Daniel

 

For the one interrested on my method of working

I do first a set of line and use a mechanical integrator for the area and moment of area.
(My last one was custom built by a German engineer of 70 years old. It is a beauty. I have mostly Haff MI and planimeters.)
That give the CB longitudinal and vertical
I plot it on the Simpson calculation and put it on Works spreadsheet, which I tailored to my need.
I calculate the transverse metacenter then the usual. (weighted area, LBS per imm. and so on, the list is too long)
When that is finish, I start immediatly the weight estimate to have a rough idea of the GM
Then I start the GA and the construction plan.
I report the weight in longitudinal and vertical in Works tailored to my need.
It gave me the GM.
Then I start the ballast system to have a the final G and GM
For the sail area power I use the Dellenbough and the wind pressure.
For the mast I user some time the Euler when the situation is very unusual, and also the Kinney method, which I find in most situatrion realy good.
For the scantling I use the Lloyd's, and some other vessel I designed and proven ok.
As for performances, I don't give many thought. Depend to much of the crew.
I just predict that they will piuck at force 9
I am mainly an hysterical about the Metacenter. It is the base of all my calculation including the period of roll and acceleration.
It come from my training as a large vessel designer.
I have to make a comment: I was not alone to design ship, we are a lot on the same hull. This presision is important.
I stop using the sliding rule in the 70' and went to the pocket calculator. Since then I never turned back.
I use since the 80' Mylar and always used Rapidograph on all my design and blueprint in my own machine, a monster which followed me all the time.
I do only large scale drawing.
Daniel