# Stability Help Please!
**URL:** https://forum.gcaptain.com/t/stability-help-please/14026
**Category:** Professional Mariner Forum
**Created:** [January 20, 2015, 9:42pm UTC](https://forum.gcaptain.com/t/stability-help-please/14026 "2015-01-20T21:42:55Z")
**Posts on this page:** 20
**Page:** 1
### Author:  [@Daniel\_Ocean](https://forum.gcaptain.com/u/Daniel_Ocean)
#### Post date: [January 20, 2015, 9:42pm UTC](https://forum.gcaptain.com/t/stability-help-please/14026/1 "2015-01-20T21:42:55Z")
Hello,
I am completing a draught surveying course in Aus, i am doing it via correspondence and unfortunately the institute did not supply me with any resources on stability, only on surveying.
I am having some issues working the below questions out. If someone could please help and show me the workings it would be much appreciated.
Thank you in advance.
A vessel of 4500 tonnes displacement and floating upright, fills a port double bottom tank
with 120 tonnes of water ballast. The centre of the tank is 4.5 m from the centre line and has
a VCG of 0.75 m. The original KG of the vessel is 4.5 m. Find the list the vessel will take, if
the KM remains constant at 5.1 m.
1. A vessel of 8500 tonnes displacement with a beam of 20 m, KG 6.25 m and KM 7.1 m, lifts
a weight of 45 tonnes with her own gear from the wharf. Height of crane jib is 24.3 m above
the keel and the weight is placed on the wharf 3 m from the ships side. (Displacement does
not include the weight and the KM remains constant).
Find the maximum list the vessel will take as she makes this lift.
---
### Author:  [@Topsail](https://forum.gcaptain.com/u/Topsail)
#### Post date: [January 22, 2015, 8:32am UTC](https://forum.gcaptain.com/t/stability-help-please/14026/2 "2015-01-22T08:32:47Z")
[QUOTE=Daniel Ocean;152436]Hello,
I am completing a draught surveying course in Aus, i am doing it via correspondence and unfortunately the institute did not supply me with any resources on stability, only on surveying.
I am having some issues working the below questions out. If someone could please help and show me the workings it would be much appreciated.
Thank you in advance.
A vessel of 4500 tonnes displacement and floating upright, fills a port double bottom tank
with 120 tonnes of water ballast. The centre of the tank is 4.5 m from the centre line and has
a VCG of 0.75 m. The original KG of the vessel is 4.5 m. Find the list the vessel will take, if
the KM remains constant at 5.1 m.
[/QUOTE]
KG(f) = Moment(f) ÷ Displacement(f)
KG(f) = {(4500 x 4.5) + (120 x 0.75)} ÷ (4500 + 120)
KG(f) = {(20,250) + (90)} ÷ 4,620
KG(f) = 4.4
GM(f) = Km – KG(f)
GM(f) = 5.1 – 4.4
GM(f) = 0.7
GG1 = Moment(f) ÷ Displacement(f)
GG1 = (120 x 4.5) ÷ (4500 + 120)
GG1 = (540) ÷ (4,620)
GG1 = 0.12
Tang List = GG1 ÷ GM(f)
Tang List = 0.12 ÷ 0.7
Tang List = 0.171429
Cot List = 9.7°
---
### Author:  [@Topsail](https://forum.gcaptain.com/u/Topsail)
#### Post date: [January 22, 2015, 8:56am UTC](https://forum.gcaptain.com/t/stability-help-please/14026/3 "2015-01-22T08:56:07Z")
[QUOTE=Daniel Ocean;152436]Hello,
I am completing a draught surveying course in Aus, i am doing it via correspondence and unfortunately the institute did not supply me with any resources on stability, only on surveying.
I am having some issues working the below questions out. If someone could please help and show me the workings it would be much appreciated.
Thank you in advance.
1. A vessel of 8500 tonnes displacement with a beam of 20 m, KG 6.25 m and KM 7.1 m, lifts
a weight of 45 tonnes with her own gear from the wharf. Height of crane jib is 24.3 m above
the keel and the weight is placed on the wharf 3 m from the ships side. (Displacement does
not include the weight and the KM remains constant).
Find the maximum list the vessel will take as she makes this lift.[/QUOTE]
KG(f) = Moment(f) ÷ Displacement(f)
KG(f) = {(8,500 x 6.25) + (45 x 24.3)} ÷ (8,500 + 45)
KG(f) = {(53,125) + (1,093.5)} ÷ 8545
KG(f) = 6.35
GM(f) = KM – KG(f)
GM(f) = 7.1 – 6.35
GM(f) = 0.75
GG1 = Moment(f) ÷ Displacement(f)
GG1 = (45 x (20 ÷2 + 3)) ÷ (8,500 + 45)
GG1 = (585) ÷ (8,545)
GG1 = 0.068
Tang List = GG1 ÷ GM(f)
Tang List = 0.068 ÷ 0.75
Tang List = 0.0906667
Cot List = 5.2°
---
### Author:  [@c.captain](https://forum.gcaptain.com/u/c.captain)
#### Post date: [January 22, 2015, 12:13pm UTC](https://forum.gcaptain.com/t/stability-help-please/14026/4 "2015-01-22T12:13:20Z")
effing smartypants…
if you weren’t a Canoodian, I’d swear you were a KPee’r
---
### Author:  [@Topsail](https://forum.gcaptain.com/u/Topsail)
#### Post date: [January 22, 2015, 12:27pm UTC](https://forum.gcaptain.com/t/stability-help-please/14026/5 "2015-01-22T12:27:09Z")
[QUOTE=c.captain;152523]effing smartypants…
if you weren’t a Canoodian, I’d swear you were a KPee’r[/QUOTE]
and I’d be …
---
### Author:  [@c.captain](https://forum.gcaptain.com/u/c.captain)
#### Post date: [January 22, 2015, 12:43pm UTC](https://forum.gcaptain.com/t/stability-help-please/14026/6 "2015-01-22T12:43:32Z")
[QUOTE=Topsail;152524]and I’d be …[/QUOTE]
you mean you aren’t already? you’re a pilot for Christ’s sake!
---
### Author:  [@Topsail](https://forum.gcaptain.com/u/Topsail)
#### Post date: [January 22, 2015, 12:47pm UTC](https://forum.gcaptain.com/t/stability-help-please/14026/7 "2015-01-22T12:47:33Z")
Can’t complain but can’t compare …
> **[Sen. John Kerry docks new boat in Rhode Island, saving taxes](http://www.masslive.com/news/index.ssf/2010/07/sen_john_kerry_docks_new_boat.html)**
>
> Kerry is docking his family's new $7 million yacht in neighboring Rhode Island.
---
### Author:  [@c.captain](https://forum.gcaptain.com/u/c.captain)
#### Post date: [January 22, 2015, 12:49pm UTC](https://forum.gcaptain.com/t/stability-help-please/14026/8 "2015-01-22T12:49:45Z")
[QUOTE=Topsail;152527]Can’t complain but can’t compare …[/QUOTE]
I’ll be the first to admit that American ship pilots make more than a bloody heart surgeon…simply criminal how much those self absorbed prima donas get!
---
### Author:  [@Topsail](https://forum.gcaptain.com/u/Topsail)
#### Post date: [January 22, 2015, 12:55pm UTC](https://forum.gcaptain.com/t/stability-help-please/14026/9 "2015-01-22T12:55:31Z")
I look more like this one … 😃
[//youtu.be/5huHlK4gkiU](https://youtu.be/5huHlK4gkiU)
---
### Author:  [@Topsail](https://forum.gcaptain.com/u/Topsail)
#### Post date: [January 22, 2015, 1:01pm UTC](https://forum.gcaptain.com/t/stability-help-please/14026/10 "2015-01-22T13:01:52Z")
[QUOTE=c.captain;152528]I’ll be the first to admit that American ship pilots make more than a bloody heart surgeon…simply criminal how much those self absorbed prima donas get![/QUOTE]
I don’t know about their income taxes, insurance costs, liability protection bills, corporation fees, pension plan and so on, deducted from the gross. If anything can go wrong, it will, at the most inopportune time, be all the pilot’s fault and everyone will know it. There’s a price for that legal liability risk. If you don’t believe me, ask the bridges!
And at the end of the day, the pilots are the ones who risk the most to finish before a heart surgeon…
---
### Author:  [@skip\_jiblet](https://forum.gcaptain.com/u/skip_jiblet)
#### Post date: [January 22, 2015, 2:23pm UTC](https://forum.gcaptain.com/t/stability-help-please/14026/11 "2015-01-22T14:23:38Z")
[QUOTE=c.captain;152528]I’ll be the first to admit that American ship pilots make more than a bloody heart surgeon…simply criminal how much those self absorbed prima donas get![/QUOTE]
It’s called legal extortion what the pilots are doing.
---
### Author:  [@Topsail](https://forum.gcaptain.com/u/Topsail)
#### Post date: [January 22, 2015, 4:23pm UTC](https://forum.gcaptain.com/t/stability-help-please/14026/12 "2015-01-22T16:23:48Z")
[QUOTE=skip jiblet;152535]It’s called legal extortion what the pilots are doing.[/QUOTE]
Holy Tug Driver … another perturbed loyal of this web site brotherhood, barking on pilots, but can’t answer the issue title!!!
If a pilot would make 100k grand a year, how much would you get? They’re the ones who pull the salary up! Just think about it capt…
---
### Author:  [@c.captain](https://forum.gcaptain.com/u/c.captain)
#### Post date: [January 22, 2015, 5:29pm UTC](https://forum.gcaptain.com/t/stability-help-please/14026/13 "2015-01-22T17:29:21Z")
[QUOTE=Topsail;152532]And at the end of the day, the pilots are the ones who risk the most to finish before a heart surgeon…[/QUOTE]
I just love this. We call out pilots for making far too much and all they can do is to come up with excuses with no humility whatsoever!
GUESS WHAT? YOU PILOTS ARE NOT HEART SURGEONS BUT SHIP DOCKERS…PERIOD!
-
-
- Updated - - -
[QUOTE=Topsail;152531]I look more like this one … :D[/QUOTE]
you should be ASHAMED!
---
### Author:  [@z-drive](https://forum.gcaptain.com/u/z-drive)
#### Post date: [January 22, 2015, 8:05pm UTC](https://forum.gcaptain.com/t/stability-help-please/14026/14 "2015-01-22T20:05:27Z")
> [@"c.captain"](#):
>
> GUESS WHAT? YOU PILOTS ARE NOT HEART SURGEONS BUT SHIP DOCKERS…PERIOD!
```
Ha ha ha in many places I go the bigshot big money pilot doesn't even dock the ship but still collects the big money! They have a "Mickey mouse" docking pilot for that who's usually far more skilled, and takes the con miles from the berth.
```
With that said, I better get off the interwebz and back to studying for my next piece of pilotage.
---
### Author:  [@Topsail](https://forum.gcaptain.com/u/Topsail)
#### Post date: [January 23, 2015, 6:57am UTC](https://forum.gcaptain.com/t/stability-help-please/14026/15 "2015-01-23T06:57:54Z")
[QUOTE=c.captain;152540]I just love this. We call out pilots for making far too much and all they can do is to come up with excuses with no humility whatsoever!
GUESS WHAT? YOU PILOTS ARE NOT HEART SURGEONS BUT SHIP DOCKERS…PERIOD!
[/QUOTE]
I really would like to know if you would appreciate the pilot sustenance to its just value, if you would be;
- called at midnight to board a Post Panamax VLCS at 04h00 way offshore into rough seas or fog,
- jump from a rocking pilot boat to a rope ladder with a back pack filled with electronics,
- climb a 60 foot gangway followed by a 130 stepladder hike to the bridge,
- taking the con while connecting your electronics, answering passage planning issue, VTS CIP reporting, …
- piloting the VLCS through congested waterway beset with high winds, changing currents or fog,
- swinging and docking stern first with the assistance of tugs looking more like toys, obeying every words,
- passing through all kinds of security checks like you were a terrorist,
- driving back home into traffic to get some rest during daylight prior the next call at midnight,
… and all that, connected to a ecg and adrenaline surge monitor so that we could show results on line to understand why you get a paycheck!
You would not succeed because you lose too much energy at barking…
---
### Author:  [@Topsail](https://forum.gcaptain.com/u/Topsail)
#### Post date: [January 23, 2015, 7:05am UTC](https://forum.gcaptain.com/t/stability-help-please/14026/16 "2015-01-23T07:05:30Z")
[QUOTE=c.captain;152540]you should be ASHAMED![/QUOTE]
Please, don’t prove us that you cannot rise yourself above the first level! 😃
---
### Author:  [@c.captain](https://forum.gcaptain.com/u/c.captain)
#### Post date: [January 23, 2015, 2:08pm UTC](https://forum.gcaptain.com/t/stability-help-please/14026/17 "2015-01-23T14:08:05Z")
[QUOTE=Topsail;152584]Please, don’t prove us that you cannot rise yourself above the first level! :D[/QUOTE]
WHAT THE FUCK? I am much more dignified than to sing Karaoke on the bridge of any ship. What will be next? Judy Garland or Barbara Streisand? Feather boas, high heels and sequined floor length gowns as well? (I do look simply stunning in purple and pearls myself!)
---
### Author:  [@Chief\_Seadog](https://forum.gcaptain.com/u/Chief_Seadog)
#### Post date: [January 23, 2015, 5:37pm UTC](https://forum.gcaptain.com/t/stability-help-please/14026/18 "2015-01-23T17:37:59Z")
With all due respect to the various posters, it [B]was[/B] Topsail who took the time to answer the OP’s stability question. I hope it was appreciated.
---
### Author:  [@c.captain](https://forum.gcaptain.com/u/c.captain)
#### Post date: [January 23, 2015, 6:05pm UTC](https://forum.gcaptain.com/t/stability-help-please/14026/19 "2015-01-23T18:05:39Z")
[QUOTE=Chief Seadog;152659]With all due respect to the various posters, it was Topsail who took the time to answer the OP’s stability question. I hope it was appreciated.[/QUOTE]
that is for the original poster to say…anyone who has sat for their master’s license would be able to answer the questions just as easily. I myself get extremely perturbed with the idiotic minutia of professional testing. Answering esoteric questions does not prove ability!
btw, it wasn’t me know posted the vid of the pilot singing karaoke acting like a fool…the man looks like John Cota!
---
### Author:  [@aaronjod](https://forum.gcaptain.com/u/aaronjod)
#### Post date: [January 31, 2016, 2:29pm UTC](https://forum.gcaptain.com/t/stability-help-please/14026/20 "2016-01-31T14:29:58Z")
Hey Guys,
Sorry to dig up an old thread. Correct me if I’m wrong but it appears you have made a mistake with the first question?
Here’s my corrections…
KG(f) = Moment(f) ÷ Displacement(f)
KG(f) = {(4500 x 4.5) + (120 x 0.75)} ÷ (4500 + 120)
KG(f) = {(20,250) + (90)} ÷ 4,620
KG(f) = 4.4
GM(f) = Km – KG(f)
GM(f) = [B]5.1 – 4.4 (Isn’t the KG 4.5?)[/B]
GM(f) = 0.[B]6[/B]
GG1 = Moment(f) ÷ Displacement(f)
GG1 = (120 x 4.5) ÷ (4500 + 120)
GG1 = (540) ÷ (4,620)
GG1 = 0.12
Tang List = GG1 ÷ GM(f)
Tang List = 0.12 ÷ 0.[B]6[/B]
Tang List = 0.[B]2[/B]
Cot List = [B]11.3[/B]°
Be great if you guys could verify to see if I’m on the right track.
Thanks,
Aaron
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