Need your advise on some reconstructed waterlines

[Redshirt]

Hi,

I once again need your advise. After playing a bit with CAD i tried to somehow get Boudriot's Jacinthe plans working (probably for the 192th time ) for me. Im not even certain if i ever use them to build something but recreating waterlines (by drawing frames based on Boudriot's lines, then "correcting them" and finaly drawing my own waterlines based upon the new frames which then are used to mutualy correct each other) can be a joy on it's own.

 

Tbh, i just wanted to know if my newly drawn waterlines appear feasable or if i have failed to notice something.

 

Thanks in advance,

Daniel

[druxey]

Always 'prove' the lines using proof diagonals. These are essentially waterlines at about a 45 degree angle. They will quickly show if things are out of fair.

[Redshirt]

Always 'prove' the lines using proof diagonals. These are essentially waterlines at about a 45 degree angle. They will quickly show if things are out of fair.

 

Thanks for the answer but im not quite certain how these proof diagonals work. Can you please elaborate?

[russ]

Once you have produced a set of body sections drawn from your waterlines, you can extend diagonal lines across the body sections, from the centerline down at angles so that the diagonal lines intersect the body sections at as close to right angles as possible.

 

Then, measuring down each line to each body section, plot those distances on your half breadth plan at each station line, opposite the waterlines and connect the dots much like you did on the waterlines. The diagonal lines on the half breadth will not have any concave curves in them because they cross the body sections at, or nearly at, right angles. There may be areas that approach a straight line, but other than that, the lines will have some convexity. It is the result of the diagonal lines in the body sections crossing at nearly right angles to the body sections.

 

These diagonal lines in the half breadth will show you where you have unexpected humps or dips in the body sections, and thus in the waterlines. I would also include three buttock lines as well. Thus, using the waterlines, buttocks, and diagonals, you can correct each, checking back and forth for each body section, until you have faired the drawing. It is a time consuming and painstaking process, but it is the best way to produce a plan from which you can build.

 

Russ

[Redshirt]

Once you have produced a set of body sections drawn from your waterlines, you can extend diagonal lines across the body sections, from the centerline down at angles so that the diagonal lines intersect the body sections at as close to right angles as possible.

 

Then, measuring down each line to each body section, plot those distances on your half breadth plan at each station line, opposite the waterlines and connect the dots much like you did on the waterlines. The diagonal lines on the half breadth will not have any concave curves in them because they cross the body sections at, or nearly at, right angles. There may be areas that approach a straight line, but other than that, the lines will have some convexity. It is the result of the diagonal lines in the body sections crossing at nearly right angles to the body sections.

 

These diagonal lines in the half breadth will show you where you have unexpected humps or dips in the body sections, and thus in the waterlines. I would also include three buttock lines as well. Thus, using the waterlines, buttocks, and diagonals, you can correct each, checking back and forth for each body section, until you have faired the drawing. It is a time consuming and painstaking process, but it is the best way to produce a plan from which you can build.

 

Russ

 

Are these the diagonals (example from Mahuna's Dunbrody thread) we are speaking about?

Edited February 8, 2017 by Redshirt

[russ]

Here is an example of an unfinished three view lines drawing that has been roughly faired using waterlines, buttock lines, and diagonals. There are 5 waterlines including the deck and rail lines. There are three buttock lines; I have also included a bearding line that appears in the sheer profile drawing as a fourth buttock line, but ignore it for this discussion. There are three diagonals.

 

The half breadth has the waterlines on the top and the diagonal lines below. The sheer profile has the three buttock lines.

 

You measure down the length of the diagonal on the body section, taking a measurement at each body section it intersects. Transfer these measurements out along the corresponding straight station line on the half breadth. Do this with each diagonal at each station and then connect the dots.

 

Russ

[Redshirt]

Many thanks, it all makes sense now!

[druxey]

Other correspondents have beaten me to the draw. An additional note: proof diagonal lines always form smooth convex lines, unlike waterlines that frequently have reversing curves.