Thickness and weight in “Design hydrostatics report”

[iosif gross]

Hi
Can’t figure out how to get thickness and weight in the “Design hydrostatics report”

I defined mean thickness at Home/Project settings/Hydrostatics/Mean shell thickness as 6 mm but in the report under
“The following layer properties are calculated for both side of the ship”
I am getting: Area; LCG; VCG
Not getting: Thickness; Weight; TCG.

Where I suppose to assign thickness and weight of the material used as it will be much different using plywood, steel GRP epoxy-glass or some sandwich.

I can calculate the weight manually as I know the weight of the plywood with epoxy glass I am using but it will be nice to get thickness and weight in the report 🙂

Best wishes
Iosif

[iosif gross]

I read over the manual but I didn’t find answer to my question.
Maybe Maarten or Marven can tell me what to do?

Best wishes
Iosif

[Icare]

I assume it’s because Delftship was conceived first to design ships, before building them. Knowing the weight and center of gravity is useful to balance the ship, and this must be done before cutting the planks.
That’s why the report is called “Hydrostatics”.

I assume there are two solutions to your problem for the next versions:
– either to include the possibility for the user to check boxes to set the report content;
– either to include a definitely new kind of report called “planks list” or something like this.

As far as I remember, you have the data you want in the LAYERS dialogue box. Maybe you can make a screenshot of it…

[iosif gross]

Hi Icare

Thank you very much for the answer. I was thinking that I am missing something substantial in using Delft Ship 🙂

I am using Delft Ship to design small boats and building them from plywood covered with fiberglass.
The easiest way to build them (for me 🙂 , I am using stitch and glue technique now) is by making an external jig so for example if I am using 6 mm plywood the boat shell is bigger by 6 mm.

Telling the truth, I don’t know how to use the LAYERS dialogue box (shame on me 🙁 )

What I have done is made a new .fbm bigger by 6 mm. It come out that the displacement on a 3 meter boat is bigger by 3 kg.
Regarding weight and CG, I succeed to make the designs in a way that the weight for and aft from the LCB is almost equal.
The bigger boats are scale-up of the smaller ones so it keeps the proportions.

I will continue with this approach if Delft Ship will not take in consideration weight and shell thickness.
Maybe someone else will find also useful my primitive approach

Thank you again
Best wishes
Iosif

[Icare]

Telling the truth, I don’t know how to use the LAYERS dialogue box (shame on me 🙁 )

BOOOO!!!!! :laugh:
Using layers is really not difficult.

You can consider them as transparent sheets you can draw on. You can draw each part of the model on its own sheet (hull, transom, deck, etc. or plank n°1, plank n°2, etc.). This allows you to display only the sheets you need when the model begins growing more and more complex.

Using layers allows you to use a pretty interesting function: layers intersections. For example I drew a rowboat using rectangular planks (like you get them from the saw mill), I rotated them (to know which was the bottom, the side and the deck), I bend them inward, I asked DelftShip find the layers’ (planks’) intersection. The model was almost complete! :woohoo:

You can assign these layers their own characteristics, such as color, transparency, and, more interesting, thickness and density. For example, on a little rowboat, you can choose a 8mm thick plank for the bottom, two 5mm thick planks for the sides and a 16mm thick plank for the transom (to attach the out-board motor on). With such different planks, where will be the CG? What will be the final weight? DelftShip can give you the answer, provided you feed it with the right data. B)

Concerning the planks’ thickness, you may ask DelftShip draw an OFFSET SURFACE base on the hull and desck, using the plywood thickess for offset distance. This will give you the planks’ inner face, and you may use this new surface to draw the bulkheads.

Just remember:
– that however it’s spread over many layers, the hull must be only one continuous surface.
– don’t forget to choose the right layer before begining drawing (just like you must make sure you’re cutting the right plank in the real life!).

Spend a couple of hours studying the layers’ use may be really helpful. 😉

[iosif gross]

Thank you again Icare for the detailed answer 🙂

I will do that, but right now I have no time and I know it will take me more than a couple of hours.
You can’t teach old dog new tricks 😛
But I will invest time in it in the future.

Best wishes
Iosif

[iosif gross]

Hi Icare

I must to thank you again 🙂
Your proposal was so simple to implement and works wonderful.
I suppose I was too lazy, that’s all :blush:

Best wishes
Iosif

[Author]

Posts