# Damage Extent, Damage Stability

Discussion in 'Stability' started by Leopard, Nov 22, 2021.

Tags:
1. Joined: Nov 2021
Posts: 43
Likes: 3, Points: 8
Location: Belgium

### LeopardJunior Member

Hi,
Could you please explain the damage extent terms?

For example the length of the each of the compartments presented in the attached image is 6m , and Forepeak tank is 4m in length. FORT -1,2 each are 3m wide.

My questions are:
1. What is longitudinal extent and transverse extent in side damage?
2. What is longitudinal extent and transverse extent in Bottom Damage?
3. In case of vertical extent what does it mean by "From the moulded line of the bottom shell plating at centerline upwards without limit?"

Now, if I find Longitudinal Damage extent =5m and Transverse Damage Extent 2.5 m. I have to consider one of the damage cases where FPT, Comp-3, bwt-1p get damaged together. Since FPT is is 4m but longitudinal Damage extent is 5m. Am I correct?

I also assume I need to consider a damage case like - DCase - Comp-3+Bwt-1P

Please let me know if my understanding are correct/ wrong.

4. Do I need to show progressive flooding in damage stability calculation? Is there anyway to avoid progressive flooding analysis in damage stability calculation?

5. If if Find longitudinal damage extent 5m, is it good idea to make a tank longer than 5m so that I don't need to consider several tanks together?
6. Final question is, I presume L is LWL in case of measuring longitudinal damage extent in the formula 1/3 L^(2/3), am I correct?

#### Attached Files:

• ###### Untitled.png
File size:
57.2 KB
Views:
95
Last edited: Nov 23, 2021
marufuddin0 likes this.
2. Joined: Oct 2008
Posts: 7,486
Likes: 1,368, Points: 113, Legacy Rep: 2488
Location: Japan

Leopard,
Is this a question you have at University?

kerosene likes this.
3. Joined: Nov 2021
Posts: 43
Likes: 3, Points: 8
Location: Belgium

### LeopardJunior Member

No, this is not a university question. I have made this question for my own understanding. I have already completed my graduation.

4. Joined: Aug 2004
Posts: 3,459
Likes: 840, Points: 113, Legacy Rep: 2040
Location: Port Orchard, Washington, USA

### jehardimanSenior Member

If they didn't teach you in University, this is what it means.

5. Joined: Nov 2021
Posts: 43
Likes: 3, Points: 8
Location: Belgium

### LeopardJunior Member

6. Joined: Apr 2010
Posts: 139
Likes: 31, Points: 28, Legacy Rep: 114
Location: Singapore

### RAraujoSenior Member - Naval Architect

Damage cases to be considered for the sketch shown (it is somewhat confusing as you have 3 tanks named fort-2p:

1. FPT
2. FPT+BWT-1p
3. BWT-1p+fort-2p (outside tank however if the border between both tanks is less than 2.5m from side shell both tanks to be considered)
4.fort-2p (outside tank however if the border between both tanks is less than 2.5m from side shell both tanks to be considered)
5. fort-1p+fort-2p (outside tank however if the border between both tanks is less than 2.5m from side shell both tanks to be considered)
6. fort-1p

Flotation and Leopard like this.
7. Joined: Nov 2021
Posts: 43
Likes: 3, Points: 8
Location: Belgium

### LeopardJunior Member

Thank you. I have corrected the naming of tanks.

8. Joined: Jan 2020
Posts: 25
Likes: 5, Points: 3
Location: China, Shanghai

### bingliJunior Member

Dear Leopard, Good day!

My anser is: It depends on what kind of ship you are working on.

If it is a dry cargo ship with reduces freeboard, you can refer to load line convention.

if it is oil tanker, you can refer to MARPOL and IBC code.

if it is Gas Carrier, you can refer to IGC code.

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.