I am a deckhand for on a ship assist tug. Last summer I was on a cruise and was amazed that this 980 ft long ship could maneuver with almost the same agility as our z-drive tractor tugs. The ship had ABB azipod thrusters which from what I can tell is very similar to the propulsion we have on our tugs. Anyways, this cruise ship never used a tug even in some of the tighter ports.
Now I can’t help but wonder…when will container vessels (and other large vessels) have the same capability? Obviously, s/b thrusters can only do so much but what this cruise ship could do was incredible. In our port we get one or two different cruise ships a week and they never use a tug. Do you envision in the near future that ship assist tugs will essentially become obsolete for routine docking and undocking work. I really don’t see how this could not be the next step in ship construction however, I have no engineering background so I’d like someone to prove me wrong.
[QUOTE=OK Corral;177415]I am a deckhand for on a ship assist tug. Last summer I was on a cruise and was amazed that this 980 ft long ship could maneuver with almost the same agility as our z-drive tractor tugs. The ship had ABB azipod thrusters which from what I can tell is very similar to the propulsion we have on our tugs. Anyways, this cruise ship never used a tug even in some of the tighter ports.
Now I can’t help but wonder…when will container vessels (and other large vessels) have the same capability? Obviously, s/b thrusters can only do so much but what this cruise ship could do was incredible. In our port we get one or two different cruise ships a week and they never use a tug. Do you envision in the near future that ship assist tugs will essentially become obsolete for routine docking and undocking work. I really don’t see how this could not be the next step in ship construction however, I have no engineering background so I’d like someone to prove me wrong.[/QUOTE]
The Cruise ships you have seen are probably Diesel/Electric powered with Pod propulsion and large bow thrusters. This is practical and economical because they usually call at a new port every day (or try to), many with no tug assistance available.
The other reason is that the hotel service requires large amount of power, which is supplied by the same multi-engine power plant.
Power requirement is dependent on whether the vessel is steaming or in port, the climate and whether day or night etc. The number of generators running depends on the need at any one time and is controlled by an automated Power Management System.
Container ships, bulkers and tankers etc. try to stay at sea as much as possible and on long voyages. The most economical propulsion system is a single slow moving Diesel engine, a large fixed pitch propeller and a slick hull with minimum of turbulence created by bow thruster tunnels etc.
Hence you find few very large bulkers/tankers with multiple propulsion engines and none with bow thrusters.
Container ships are different. Many very large container ships are twin screw and fitted with bow thruster(s), but not enough maneuverability to eliminate tugs entirely.
Conclusion: Your tug job is safe for the foreseeable future.
[QUOTE=ombugge;177418]Hence you find few very large bulkers/tankers with multiple propulsion engines and none with bow thrusters.[/QUOTE]
Not to mention the negative economics of giving up cargo space to thrusters and their associated machinery while at the same time talking on the costs of maintenance and repair.
It’s very likely more economical to carry more cargo and occasionally pay a tug company a small portion of the costs of maintenance and repair. Ship-assist tugs are like thruster time shares for shipping companies, since you only need thrusters a small fraction of the time.
There are 4 cont. Ships now that have bow thrusters. It is called Independent Container Line. They call Chester ,PA and Wilm. NC. Sometimes they sail without tugs. They are medium sized container vessels, no where similar to the new monsters out now.
I can’t really think of any box ships without a bow thruster. However Some are shit for power, others are broken. It’s normal for Panamax ships with a “good” thruster to need just one “good” tug for easy docking or sailings. This is for normal wind, current, terminal configurations mind you.
Depending on the berth and other factors small <400’ (120m for you metric folks) feeder ships can get away without tugs quite often, usually cpp and Becker rudder with a good thruster.
It’s very likely more economical to carry more cargo and occasionally pay a tug company a small portion of the costs of maintenance and repair. Ship-assist tugs are like thruster time shares for shipping companies, since you only need thrusters a small fraction of the time.[/QUOTE]
Maersk must think otherwise … the E class boats have 2 bow and 2 stern thrusters.
[QUOTE=Steamer;177461]Maersk must think otherwise … the E class boats have 2 bow and 2 stern thrusters.[/QUOTE]
Well, my reply was specifically towards “bulkers/tankers” which give up cargo space to thrusters. Container ships have a different hill design and carry different cargo.
[QUOTE=Steamer;177461]Maersk must think otherwise … the E class boats have 2 bow and 2 stern thrusters.[/QUOTE]
I don’t know about [B]2[/B] of each, but the E class does have 1 bow and 1 stern thruster, and they are quite effective.
However, the last set of Sea-Land built ships (Champion class… Racer, Champion, Intrepid, Meteor, etc… about 8 ships ) had no thrusters. And those have only been flagged out for about 3 years now.
I have seen smaller ships, particularly small-medium sized Car Carriers, use 1 tug and a line throwing gun to tie up in Toyohashi many times (in nominal weather/tide conditions). They probably had a bow thruster but it was really cool seeing them use an LTA to send a messenger to the dock for putting out their hawsers.
[QUOTE=Johnny Canal;177486]I don’t know about 2 of each, but the E class does have 1 bow and 1 stern thruster, and they are quite effective.
However, the last set of Sea-Land built ships (Champion class… Racer, Champion, Intrepid, Meteor, etc… about 8 ships ) had no thrusters. And those have only been flagged out for about 3 years now.
I have seen smaller ships, particularly small-medium sized Car Carriers, use 1 tug and a line throwing gun to tie up in Toyohashi many times (in nominal weather/tide conditions). They probably had a bow thruster but it was really cool seeing them use an LTA to send a messenger to the dock for putting out their hawsers.[/QUOTE]
Bow thruster is becoming more common on smaller vessels, especially Container feeders, MP Cargo ships and special purpose vessels up to Handymax size, but VERY rear on anything bigger, except large Container ships.
Maybe this is what you have seen on Car carriers?
A common tool on Japanese ships and, in this case, a Japanese Rig, the Hakuryu V:
I have to laugh as a tugboat guy at some shit people think up. If it’s too tough to get close enough to put up a line it’s too rough for me to put any strain on it great enough to steer or slow a ship down etc.
Dead ship in open water with a drifting ship is different.
[QUOTE=z-drive;177492]I have to laugh as a tugboat guy at some shit people think up. If it’s too tough to get close enough to put up a line it’s too rough for me to put any strain on it great enough to steer or slow a ship down etc.
Dead ship in open water with a drifting ship is different.[/QUOTE]
In the case of his example, a drilling rig making up to large offshore tug / AHTS.
[QUOTE=z-drive;177492]I have to laugh as a tugboat guy at some shit people think up. If it’s too tough to get close enough to put up a line it’s too rough for me to put any strain on it great enough to steer or slow a ship down etc.
Dead ship in open water with a drifting ship is different.[/QUOTE]
On a ship this is used to pass first lines ashore, or to shoot a line to make up Emergency tow.
On a rig it is used differently, which was what described.
It is a handy tool, especially when the AHT has problem coming close enough to reach with normal heaving line, or by crane.
The heaving line skills among rig crews sometime leave something to desire as well.
You can of cause use it to shoot a line to a harbour tug as well, but you need a bit of deck to aim for.
To try hitting the bow winch may not be smart, especially if the tug crew is not familiar with this type of “gun” and know how to hide.
I have only seen it on Japanese rigs and ships. Anybody seen it elsewhere??
Yes, they are handy offshore. I’ve used a “shoulder” mounted one powered by SCBA tanks. But since we were discussing tugs and shiphandling, i figured this was the context.
[QUOTE=tugsailor;177502]I have always wanted a cheap, practical, reuseable line throwing gun, but that big wooden (it looks like wood) window weight looks scary.[/QUOTE] http://restech.no/products/complete-sets/plt-rescue-230
[QUOTE=tugsailor;177502]I have always wanted a cheap, practical, reuseable line throwing gun, but that big wooden (it looks like wood) window weight looks scary.[/QUOTE]
It is plastic and foam filled to float if ending up in the water.
