Big ship bottom painting

[Keith]

For you Navy and ship people. I'm assuming they use anti-fouling paint on the bottom, right? I understand they also get to use the tin based paint, but correct me if I'm wrong. So how often do they do it and do they have to dry dock the ship? I'm assuming they do, but for all I know they've found a way to do that in the water or get rid of the necessity altogether. Inquiring minds...

 

[Tidahapah]

Keith,
Even the big ships have now had to get away from tin based antifoul.
Usually done every 5 years these days.
Some vessels may get a scrub after 2 1/2 to 3 years if speed / efficiency drops off.
Most Gas Buggies (LNG tankers) dock every 12 months and usually an as new docking.
Very expensive ships that they expect to have a long life and usually tied into a pretty tight charter agreement re voyage schedules.
Benn

 

[FF]

www.marinelink.com is the site for Maritime Reporter and Engineering News.

The Sept 2010 issue is their "Marine Coatings" issue and If you can pull it up will let you know what the big guys use.

http://www.marinelink.com/magazines/default.aspx

And hit the Sept issue , it will download for you.

-- Edited by FF on Tuesday 5th of October 2010 08:25:46 AM

 

[Keith]

So how do they get say, an aircraft carrier out of the water for painting? Big submersible floating dock?

 

[Larry M]

I took this picture when were in New London, South Africa.* The dry dock was* getting ready to accept a ship.* You can see the guys below moving the solid steel blocks for the next vessel.* I'm not sure what the biggest ship they can handle but it could handle anything I've ever have been on.

Larry/Lena
Hobo KK42
La* Paz, BCS, MX

-- Edited by Larry M on Wednesday 6th of October 2010 08:59:46 AM

 

[COCG47]

US Navy ships generally drydock on a 5 year interval, and the bottom (and usually the whole hull) get taken down to parade rest and repainted.* There*are also regular inspections and mechanical cleanings of the bottoms, sea chests, running gear, sonar dome, etc., with the ship in the water (at least yearly).* These are all part of the ship's lifecycle maintenance plan.* I'm not sure what they are using for paint now, but I'm sure with all the environmental constraints, that it is not the same as in the past.

Believe east coast aircraft carriers drydock at either Norfolk Naval Shipyard in Portsmouth, VA, or at Newport News Shipbuilding.* Not sure where they dock on the west coast.* Small boys (Cruisers, Destroyers, Frigates, Amphibs) can drydock at any number of commercial shipyards on both coasts.* When I was in command of my ship, we drydocked at Bender Shipyard (now Signal) in Mobile AL, and when I had command of*a Destroyer Squadron in Mayport FL, all my ships drydocked at Atlantic Marine on the St Johns River in Jacksonville.* Both of those are floating drydocks.* Atlantic Marine also has a marine railway that can pull a Frigate or USCG cutter out of the water.* Pretty cool...

Glenn
CAPT Glenn Zeiders, USN
M/V SYREN
Jefferson 46

 

[markpierce]

Aren't some commercial ships the size of aircraft carriers such as the Maersk Sofia, pictured here in San Francisco Bay?* (Someone told me it would take 20 trains a mile-and-a-half-long each with double-stack railroad cars to carry the ship's containers.)

(Picture quality compromised by water-spotted window of a ferry.)

 

[FF]

When a few dozen of those boxes get blown off , and float barely awash ,

one might wonder why there are is no collision bulkhead in his boat.

Might even wonder why no Water Tight Bulkheads , in what is sold as an "offshore boat".

 

[RickB]

Those who run the ICW through Norfolk/Portsmouth pass by*a*floating drydock the Navy uses for carriers in that area.

Here it is with an LPA undergoing*some refit*work.



The great picture Larry M posted is a "graving dock" and while there are several on the US West Coast they are no longer in commercial service. Since the Port of Portland Oregon sold the largest floating dry dock on the West Coast to a shipyard in the Bahamas, our large ship repair business has gone to China and Singapore.



-- Edited by RickB on Thursday 7th of October 2010 09:40:56 AM