Stem thickness and bottom board

[Jean -Paul Carrier]

Could someone help me with the following problem?
I have started modelling a Wherry (taken from John Gardner’s book “Building Classic Small Craft”) and so far it has gone fairly weel with the Hull modelling tutorial and background images. At this point however, I would like to show the thickness of the stem. I have tried selecting the stem points and moving them one inch in the transversal direction and it works, but then it distorts the adjacent chines, in particular the bottom board, which is no more centered near the stem. I would also like to show the square end of the bottom board (where the stem comes to sit – in this particular case, the end of the bottom board is 2 inches wide and is perpendicular to the center line). Is this possible in Delftship?

I would appreciate comments from knowledgeable users of Delftship. I am new to the program and I appreciate its capacity to develop planks on a plane surface without having to spill them in the traditional way.

[Sean Russell]

I will be interested in the answers as I am dealing with the same issue. It has occurred to me that one could move the entire hull away from the centre line by one half the width of the portioin of the stem you wish to have exposed. So if you wanted a flat surface on the stem (so you could add a false stem to cover the plank ends) of one half inch you would move the hull away from the centre line by one quarter of an inch. Your hull would be somewhat wider and you would have to make allowances for this but it should work.

Sean

[Jean -Paul Carrier]

Thanks for your comment Sean. Interesting point. Since I do not have to make hydrostatic calculations for a wherry, it would probably not matter if there is a gap in the middle of the boat! The stem line on the model is in fact the rabbet line (where the plank touches the stem); therefore, plank development would presumably not be affected by the procedure you describe. Lets see what others have to say about this…

Jean-Paul

[Icare]

Well, I hope I got it right…
(Pfew! :pinch: Two Frenchmen discussing in english…)

I understood you selected the stem’s edge and moved it in the transversal direction (screenshot #1)… but this opened the hull’s bow (screenshot #2) and you want to close it and leave a flat space for the false stem. And, as I assume you drew the bottom board and the side board on different layers (don’t worry, this is the right way to do 😉 ), the operation will be a (very!) little harder than if the whole hull was drawn on an only layer.

The stem’s closing:
I begin by this one because I think it’s easier and the result can be appreciated immediately. :woohoo:
Using the side board’s layer (or the very stem’s layer if any), select the segment of the stem’s edge (the one you moved away from the symmetry plane), and extrude it back towards the symmetry plane (this will draw the side board’s thinkness and close the stem)(screenshot #2).

The bottom’s closing:
Look, there’s a long triangular split in the bottom board, just behind the stem’s foot.
Using the bottom board’s layer, select the triangular split’s edges and close it (screenshot #3)! This is just the best and easiest way I found to finish the job 😉 (screenshot #4).
Now, check for the knuckle lines: creases for the side board and round for the bottom board.

But instead of closing the stem, you can draw the false stem, too! (screenshot #5) You already know the required operations 😉

Don’t forget to use the convenient layers!

Of course, during the operations, toggle the model display on “wireframe” (I toggled it on shade just to help you figuring out my speech).

Si tu préfères, je peux te le refaire en français 😉

Attachments:

• 1.frontview.jpg
• 2.Stemopening.jpg
• 3.Stemclosing.jpg
• 4.Settingcreases.jpg
• 5.Falsestem.jpg

[Jean -Paul Carrier]

Merci, Icare, pour tes conseils et suggestions. Très apprécié. Pour ce qui est de la langue je dois dire que mon vocabulaire des termes de marine (en tout cas en ce qui a trait à la construction de petits bateaux en bois) est surtout anglais; de plus, les logiciels que j’ai utilisés depuis une dizaine d’années sont en anglais. Il n’y a donc pas de problème à ce que tu répondes en anglais. Comme tu auras noté aussi, je suis débutant avec Delftship. Des conseils comme les tiens sont donc d’autant plus bienvenus et appréciés. Merci encore.

Jean-Paul

[Icare]

We all have been a beginner with Delftship, and I don’t forget how puzzled I was with it on the begining.
If you wish to improve, the secret is to read the manual again and to practice, again and again. And only once you’re sure you know the software you can design your real project. That’s why I draw more than ships. :silly:

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