How often do they bottom paint huge ships?

Some of the biggest ships in the world are over 1,000 ft long, and have a 80-90 ft draft.
There are only a few ports in the world that are even deep enough for these ships.
So how do they dry dock a ship this big to paint the bottom?
I guess where they built it, would be the best spot to go to dry dock it.

you think they bottom paint them 3very 5 years? every 10?
I heard the navy has a super special bottom paint that will last 10 years, but they are the only ones who can use it.

Re: How often do they bottom paint huge ships?

There's a dry dock for any ship built:

http://en.wikipedia.org/wiki/Drydock

There's been a bunch of pretty cool shows on Discovery, National Geographic & History channels that tackle some dry dock jobs. Just saw a recent World's Toughest Fixes where they had 2 weeks to do a whole host of work to a giant cruise ship in dry dock including remove the prop & shaft to fix a tiny water pipe inside the shaft housing! They repainted the bottom when they had the boat in dry dock as well.

Here's a video of them replacing an engine in a cruise ship while in dry dock! Like they say, there's always a bigger boat out there

http://www.youtube.com/watch?v=0wdek-lb5Hg

I don't know what their schedule is, but I'm sure it's extremely costly to reserve the dock & have that kind of downtime for the boat.

Re: How often do they bottom paint huge ships?

Keep in mind probably 90 percent of the ships your speaking of actually do no have a 90ft draft. the thousand footers here on the great lakes draw 28-30'. even ocean going vessels are not as deep as one would think. However your right, cruise ships and a few select others have a deeeeeeep draft. I know on the great lakes they paint the hulls ever 5 to 6 years.

Re: How often do they bottom paint huge ships?

The ships I have worked on have to be drydocked every 4 years due to required Transport Canada inspections. (thru hull fittings, shafts etc.) The anti fouling paint is done at this time not necessarily because it is needed, but the ship is already dry docked.

Re: How often do they bottom paint huge ships?

VLCC's & ULCC's (supertankers) will draw 90', however keep in mind that is only when fully loaded. Light they draw in the 20' range. But, yes they need to be pulled in order to do the job. There are all sorts of in the water scrubber systems in use these days, and commercial shipping is always on the move (not tied up in a slip 90% of the time like pleasure boats). It's a lot harder for stuff to grow on a moving target so to speak, so the growth is much slower..