Discussion in 'Software' started by pavel915, Feb 2, 2007.

1. Joined: Nov 2006
Posts: 349
Likes: 10, Points: 18, Legacy Rep: 154

### pavel915Senior Member

I need to find the weight and position of cg of the hull shell plates
so the wetted surface area and the position of the CG of hull surface will give the result.(wetted surface area*plate thickness will give me the plate volume)
now. I found that , rhino has a option analyze>massproperties>area and
analyze>massproperties>area centroid
will this give me the result I am wanting? I am a bit confused about that.
thanks.

2. Joined: Jan 2004
Posts: 2,457
Likes: 64, Points: 0, Legacy Rep: 711
Location: Trondheim, NORWAY

### Raggi_ThorNav.arch/Designer/Builder

Don't confuse wetted area with the whole hull.
For cg of the whole hull you can use the command AreaMoments.

3. Joined: Jan 2004
Posts: 2,457
Likes: 64, Points: 0, Legacy Rep: 711
Location: Trondheim, NORWAY

### Raggi_ThorNav.arch/Designer/Builder

It seems like the AreaCentroid is what you need, you ca select as many surfaces as you want.

Here is from a small boat:
Cumulative Area = 6.8288999 (+/- 1e-006) square meters for 5 surfaces
Cumulative Area Centroid = 2.387977,-3e-016,0.2387679 (+/- 3.6e-006,1.7e-006,5e-007) for 5 surfaces

This boat has the center of gravity 2.4 meter from the bow (2.387977).
Your boat (ship) is probably rotated, but you see what I mean.

Since I wasn't sure how this command works, I made a simple surface, a rectangle with one corner in 0,0,0. If you kow the answer it's easier to fihure out what Rhino calculates.

4. Joined: Nov 2006
Posts: 349
Likes: 10, Points: 18, Legacy Rep: 154

### pavel915Senior Member

oh;;;;;;;; so this is a very good thing for estimating the many parst of the ship.
It can help us a lot for weight estimate.

5. Joined: Jan 2007
Posts: 16
Likes: 0, Points: 0, Legacy Rep: 10
Location: Phoenix

### AntisthenesJunior Member

use v4?

Forum posts represent the experience, opinion, and view of individual users. Boat Design Net does not necessarily endorse nor share the view of each individual post.
When making potentially dangerous or financial decisions, always employ and consult appropriate professionals. Your circumstances or experience may be different.