stern Thruster

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[chouby-20]

Hello

somebody knows if there is a stern tunnel thruster on Fairmount Sherpa?

[redbeard]

and mabye a for and stern thruster on the tanker... It is quite weird with a ship at over 300m with no thrusters. 


Edit: Type

[groennegaard]

somebody knows if there is a stern tunnel thruster on Fairmount Sherpa?

It does not have a stern thruster in the game, but take a look at this:
http://www.oilonline.com/news/features/oe/20040801.Towing_t.15521.asp

The new 75m long vessels, set to be the 'most powerful tugs' flying the Dutch tricolour, will each weigh 2700dwt and have 200t bollard pull. Outfitted with four Wärtsilä marine diesel engines capable of 12,000kW continuous power and bow and stern thrusters with 12t and 10t thrust respectively, the Sherpa and Summit will have a top speed of 16.5 knots.

Perhaps the Sherpa should have a stern thruster after all...

Regards
groennegaard

[chouby-20]

The new AHTS have most of the time fore and aft tunnel thruster ( some of them have an azimuthal thruster forward in additon of the tunnel thruster) because they need it during rig move operation

[groennegaard]

and mabye a for and stern thruster on the tanker... It is quite werid with a ship at over 300m with no thrusters. 

Actually there is a lot of large ships that do not have thrusters and this is not weird at all. Consider the expenses a company must invest in thrusters and the power plant that feeds them... For these large ships really big and powerfull equipment is needed. Large tankers and bulkers do not have as many calls as ferries and containerships and this is why companies often choose not to install thrusters on board. They depend on tugs instead.

Take a look at the Berge Stahl...
http://www.shipsim.com/ShipSimForum/index.php/topic,49.0.html
... it does not have any thrusters at all even though it is a huge ship...

Regards
groennegaard

[redbeard]

Actually there is a lot of large ships that do not have thrusters and this is not weird at all. Consider the expenses a company must invest in thrusters and the power plant that feeds them... For these large ships really big and powerfull equipment is needed. Large tankers and bulkers do not have as many calls as ferries and containerships and this is why companies often choose not to install thrusters on board. They depend on tugs instead.

Take a look at the Berge Stahl...
http://www.shipsim.com/ShipSimForum/index.php/topic,49.0.html
... it does not have any thrusters at all even though it is a huge ship...

Regards
groennegaard

Wow!!! Nice modelling! And a Norwegian ship  Is it posible to dowload or buy it, without reading the whole thread?

Anyway.. Thnx for the explenation. It actually sounds quite logical. But the Latitude has atleast one foor thruster...
http://bayimg.com/EAElbaaBb
(click on img to get a greater view)

I know that a lot of supply ships and anchor handling ships (not the sherpa though) often have more then 2 thrusters that is linked to the GPS, for accurate possitioning...
BTW.. I was aboard an oilrig that also had that system, when it was docked just outside Bergen where I live. West Venture. It could actually lie almost still without dropping the anchors. Quite impressing.
http://bayimg.com/FaelFAAbb

I guess this was a bit off topic, sorry

[chouby-20]

it's dynamic positionning

[redbeard]

Cool.. I think its very impressing.. The GPS have to be more accurate than the comersial ones, dont it?

[chouby-20]

there is other systems in addition of gps like fan beam

[redbeard]

Thnx for info.    I want one of those on my boat to use when im fishing. 

[chouby-20]

it's a little bit expensive

[groennegaard]

Wow!!! Nice modelling! And a Norwegian ship  Is it posible to dowload or buy it, without reading the whole thread?

Anyway.. Thnx for the explenation. It actually sounds quite logical. But the Latitude has atleast one foor thruster...
http://bayimg.com/EAElbaaBb
(click on img to get a greater view)

I thought a Norwegian example would help you understand...  

Wow   I have not noticed that mark before... You are right! It should have a bow thruster then...

Regards
groennegaard

[chouby-20]

Perhaps it's a shuttle tanker?

[redbeard]

I thought a Norwegian example would help you understand...  

Hehe.. You know it. 

it's a little bit expensive

Yep, i guess... Would not be mutch space for family weekend trips either i think. lol

[Sam]

Actually there is a lot of large ships that do not have thrusters and this is not weird at all. Consider the expenses a company must invest in thrusters and the power plant that feeds them... For these large ships really big and powerfull equipment is needed. Large tankers and bulkers do not have as many calls as ferries and containerships and this is why companies often choose not to install thrusters on board. They depend on tugs instead.

Take a look at the Berge Stahl...
http://www.shipsim.com/ShipSimForum/index.php/topic,49.0.html
... it does not have any thrusters at all even though it is a huge ship...

Regards
groennegaard

Good example, even the biggest ship ever in the world doesn't have a bow or stern truster.
http://johnfenzel.typepad.com/john_fenzels_blog/images/2007/03/21/knock_nevis_009.jpg

[rs]

There is also tankers with pod propulsion, in this case there is no need for sternthruster. http://www.donsotank.se/evinco.htm

[Shipaddict]

Wow!!! Nice modelling! And a Norwegian ship  Is it posible to dowload or buy it, without reading the whole thread?

Well it has to be programmed by VSTEP but then it will be free to download for shipsim!

[Cloud]

Cool.. I think its very impressing.. The GPS have to be more accurate than the comersial ones, dont it?

Hi Redbeard,

It is possible to operate in DP with a normal GPS, however this would put undue wear and tear on your main engines and propulsion units as the signal jumps around alot and the DP system constantly will be "hunting" the setpoint.

As chouby-20 suggests there are other position reference systems; however GPS can be corrected with a Differential signal to improve the accuracy of the GPS signal and tighten up it's footprint. Depending on how much an operator wants to pay you can get accuracy into the cm range like Fugro's SDGPS service, but this kind of accuracy level is not necessary for DP operations, regular DGPS in the 1-5m accuracy is good enough.

Other position reference systems include; Acoustics(Sound ranging from beacons on the bottom), Fanbeam (close range laser range/bearing relative to reflector), Artemis (slightly longer radar ranging relative to scanner), Radius (A new microwave system by Kongsberg sort of like Artemis), Taunt-wire (like a plumb-line off the bottom), and a couple others. Depending on the Class of DP operation you are conducting you would use a combination of these position reference systems.

Sorry if this is a little off the Stern Thruster Discussion.

Cheers,

Larse

some interesting links for this topic;

General Principles - http://www.imca-int.com/divisions/marine/reference/intro04.html
HydroAcoustics - http://www.km.kongsberg.com/ks/web/nokbg0240.nsf/AllWeb/BCFCB4C4F48BD12CC1256A7E0032FD83?OpenDocument
SDGPS -  http://www.skyfix.com/fugro/skyfixxp/skyfixxp_home.cfm
Radius - http://www.km.kongsberg.com/KS/WEB/NOKBG0240.nsf/AllWeb/57E47945903AB766C12570F3003061A8?OpenDocument
Fanbeam - http://www.mdl.co.uk/dynamic_systems/fanbeam-laser-radar/index.html

[redbeard]

Thanks. Thats a lot of knowledge. 
I dont know what kind of DP system the oil rig had (West Venture), but I remember that it could operate without anchors, depending on weather conditions I guess. I will not bet on it, but I think the accuracy was about 10cm. Can probably google it. hehe..

Thanks for the links.

And thread starter: Sorry about that