# How does the Navy clean the bottom of Aircraft Carriers? **URL:** \ **Category:** Factual Questions\ **Created:** [January 9, 2006, 5:24am UTC](https://boards.straightdope.com/t/how-does-the-navy-clean-the-bottom-of-aircraft-carriers/339107 "2006-01-09T05:24:29Z")\ **Posts on this page:** 20\ **Page:** 2
**Author:** ![Gringo\_Miami](https://avatars.discourse-cdn.com/v4/letter/g/f17d59/32.png) [@Gringo\_Miami](https://boards.straightdope.com/u/Gringo_Miami)\ **Post date:** [January 9, 2006, 4:30pm UTC](https://boards.straightdope.com/t/how-does-the-navy-clean-the-bottom-of-aircraft-carriers/339107/21 "2006-01-09T16:30:10Z")
There is a difference between building a ship on land - in a shipyard - and later sliding it into the water — and servicing one in a drydock (where the ship is driven in under power (her own, or tugs or other assistance), the water drained, the ship serviced and the ship later refloated. CAUTION. The links below are to fairly large jpegs. Here are Two pictures illustrating the options. [THIS ONE OF A SHIPYARD](http://www.akeryards.com/archive/ext_AKY/Public/yards/Aker_Braila_300.jpg) shows several ships being built on dry land. These are called newbuilds. [THIS ONE OF A DRYDOCK](http://www.akeryards.com/archive/ext_AKY/Public/yards/finnyards_tku_300.jpg) shows one ship in the drydock, and another waiting. Those two cruiseships are each very large - 1,020 feet and approx 138,000 tons. Filling and/or draining a drydock of that size typically takes two days. It is done slowly to ensure that stresses on the hull are properly distributed as cradles are added and/or removed. There are several facilities in the world big enough for the large ships, including one in Mississippi (used by a lot of naval vessels) and several in Europe (Finland where the pics were taken), Germany and France. However, given the fact that there are more mega ships than drydocks to handle them… booking the drydocks is planned well in advance, years in fact, and involves a lot of planning. Since I work for a company which owns 29 mega ships, I will refrain from discussing brand names, but if you are any good, you can figure out which company from the pics… 😃 ---
**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\ **Post date:** [January 9, 2006, 4:41pm UTC](https://boards.straightdope.com/t/how-does-the-navy-clean-the-bottom-of-aircraft-carriers/339107/22 "2006-01-09T16:41:08Z")
> [@Gringo\_Miami](#): > > Since I work for a company which owns 29 mega ships, I will refrain from discussing brand names, but if you are any good, you can figure out which company from the pics… 😃 I bet I know the [real reason](http://www.equium.org/gallery/misc/titan_uranus) for your reluctance to speak about it, eh? eh? 😉 ---
**Author:** ![Gringo\_Miami](https://avatars.discourse-cdn.com/v4/letter/g/f17d59/32.png) [@Gringo\_Miami](https://boards.straightdope.com/u/Gringo_Miami)\ **Post date:** [January 9, 2006, 4:49pm UTC](https://boards.straightdope.com/t/how-does-the-navy-clean-the-bottom-of-aircraft-carriers/339107/23 "2006-01-09T16:49:41Z")
> [@Mangetout](#): > > I bet I know the [real reason](http://www.equium.org/gallery/misc/titan_uranus) for your reluctance to speak about it, eh? eh? 😉 ROTFLMAO… that is too funny! Please tell me it’s Photoshop and not real… :eek: As for my company, if you were a customer, I could promise you royal treatment, like a celebrity in fact… [Seriously, I’m new here - MODS… what is the policy on this sort of thing?? I want to stay in the rules – professional credentials versus plug – and I don’t want to plug anything here, it is not necessary.] ---
**Author:** ![AzureM](https://avatars.discourse-cdn.com/v4/letter/a/ac91a4/32.png) [@AzureM](https://boards.straightdope.com/u/AzureM)\ **Post date:** [January 9, 2006, 4:58pm UTC](https://boards.straightdope.com/t/how-does-the-navy-clean-the-bottom-of-aircraft-carriers/339107/24 "2006-01-09T16:58:12Z")
Looks like they’re playing bumper boats with the lifeboats… are they removed for regular inspections/maintenence while the ship is in dry dock? ---
**Author:** ![What\_Exit](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/what_exit/32/10652_2.png) [@What\_Exit](https://boards.straightdope.com/u/What_Exit)\ **Post date:** [January 9, 2006, 5:16pm UTC](https://boards.straightdope.com/t/how-does-the-navy-clean-the-bottom-of-aircraft-carriers/339107/25 "2006-01-09T17:16:52Z")
:smack: I am confusing terminology. I was thinking of the slipways as drydocks. I forgot they are are not the same thing. D’oh. Sorry Jim ---
**Author:** ![Raguleader](https://avatars.discourse-cdn.com/v4/letter/r/258eb7/32.png) [@Raguleader](https://boards.straightdope.com/u/Raguleader)\ **Post date:** [January 9, 2006, 5:32pm UTC](https://boards.straightdope.com/t/how-does-the-navy-clean-the-bottom-of-aircraft-carriers/339107/26 "2006-01-09T17:32:38Z")
> [@Uncommon Sense](#): > > Cite? > How would they paint the finished hull if it’s in the water? > I suppose they could assemble enough of the hull (painted) on land and then finish the upper half with the hull in the water, but why? If they have to build a large enough structure to support enough of the hull to start the project why would they not just finish it in dry dock? I suppose one reason would be if you need to start building another ship as soon as possible (basically if you’re expansing your fleet or replacing hulls in a hurry for some reason). Thus, you park the newly-floated ship into a dock nearby to finish building all the stuff it DOESN’T need for purposes of floating on the water, and you start building the next ship without having to wait to finish the first one. I’m not sure if it’s possible to push a ship back ON to a slipway (I’ve honestly been curious about that for years) but I imagine it’s pretty tricky to nigh-impossible. IIRC, the Bismark was built in the half-on-land fashion. Hull and lower bits built, slid into the water, it’s weight being announced as being within treaty limits, and then the superstructure and such being built, pushing the weight limit a good bit over the limit. :rolleyes: ---
**Author:** ![Raguleader](https://avatars.discourse-cdn.com/v4/letter/r/258eb7/32.png) [@Raguleader](https://boards.straightdope.com/u/Raguleader)\ **Post date:** [January 9, 2006, 5:33pm UTC](https://boards.straightdope.com/t/how-does-the-navy-clean-the-bottom-of-aircraft-carriers/339107/27 "2006-01-09T17:33:52Z")
> [@AzureM](#): > > Looks like they’re playing bumper boats with the lifeboats… are they removed for regular inspections/maintenence while the ship is in dry dock? Oh wow… the only word I can think of is “That’s cute!” 😛 They look like little floating bumblebees buzzing about next to the dock! 😃 ---
**Author:** ![Raguleader](https://avatars.discourse-cdn.com/v4/letter/r/258eb7/32.png) [@Raguleader](https://boards.straightdope.com/u/Raguleader)\ **Post date:** [January 9, 2006, 5:35pm UTC](https://boards.straightdope.com/t/how-does-the-navy-clean-the-bottom-of-aircraft-carriers/339107/28 "2006-01-09T17:35:44Z")
> [@AzureM](#): > > Looks like they’re playing bumper boats with the lifeboats… are they removed for regular inspections/maintenence while the ship is in dry dock? Oh, and because I thought of this after hitting “Submit Reply”, I’ve read that many larger ships use lifeboats for moving people and materiel between the ship and shore (or other ships, if needed) whenever docking the ship isn’t practical. This is no doubt also a handy way to make sure you don’t have leaky lifeboats (which, as anyone who has seen Muppet Treasure Island knows, can be a very dangerous thing to have in an emergency 😃 ) ---
**Author:** ![Gringo\_Miami](https://avatars.discourse-cdn.com/v4/letter/g/f17d59/32.png) [@Gringo\_Miami](https://boards.straightdope.com/u/Gringo_Miami)\ **Post date:** [January 9, 2006, 6:09pm UTC](https://boards.straightdope.com/t/how-does-the-navy-clean-the-bottom-of-aircraft-carriers/339107/29 "2006-01-09T18:09:03Z")
> [@AzureM](#): > > Looks like they’re playing bumper boats with the lifeboats… are they removed for regular inspections/maintenence while the ship is in dry dock? While I wouldn’t put it past the yard workers to have some fun :rolleyes: … those lifeboats are probably just being lowered off the second ship so they can be lifted into the yard for painting/maintenance etc. As for a sense of scale, you might be interested to know that each of those little bumblebees carries 150 people. ---
**Author:** ![Gringo\_Miami](https://avatars.discourse-cdn.com/v4/letter/g/f17d59/32.png) [@Gringo\_Miami](https://boards.straightdope.com/u/Gringo_Miami)\ **Post date:** [January 9, 2006, 6:14pm UTC](https://boards.straightdope.com/t/how-does-the-navy-clean-the-bottom-of-aircraft-carriers/339107/30 "2006-01-09T18:14:54Z")
> [@Gringo\_Miami](#): > > While I wouldn’t put it past the yard workers to have some fun :rolleyes: … those lifeboats are probably just being lowered off the second ship so they can be lifted into the yard for painting/maintenance etc. Sorry to correct myself… .after actually studying the pic a bit more… it looks like the ship has just come out of drydock - and the lifeboats are being driven to “mama” to be reloaded AFTER having been serviced. The giveaway is that the paint on each of the lifeboats is bright… they tend to fade in the sun over time. ---
**Author:** ![Drum\_God](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/drum_god/32/44_2.png) [@Drum\_God](https://boards.straightdope.com/u/Drum_God)\ **Post date:** [January 9, 2006, 6:32pm UTC](https://boards.straightdope.com/t/how-does-the-navy-clean-the-bottom-of-aircraft-carriers/339107/31 "2006-01-09T18:32:15Z")
> [@Raguleader](#): > > Oh, and because I thought of this after hitting “Submit Reply”, I’ve read that many larger ships use lifeboats for moving people and materiel between the ship and shore (or other ships, if needed) whenever docking the ship isn’t practical. This is no doubt also a handy way to make sure you don’t have leaky lifeboats (which, as anyone who has seen Muppet Treasure Island knows, can be a very dangerous thing to have in an emergency 😃 ) On a cruise vacation in the Caribbean, one of our ports (Grand Cayman) was a “tendered” port. Two of the lifeboats were used as passenger tenders. One of the tenders was the lifeboat that me and my family were assigned to. I always wondered what we were to do if the ship were in distress while my lifeboat was running taxi duty. I would go to my muster station, but no lifeboat would be there. :eek: ---
**Author:** ![Gringo\_Miami](https://avatars.discourse-cdn.com/v4/letter/g/f17d59/32.png) [@Gringo\_Miami](https://boards.straightdope.com/u/Gringo_Miami)\ **Post date:** [January 9, 2006, 6:43pm UTC](https://boards.straightdope.com/t/how-does-the-navy-clean-the-bottom-of-aircraft-carriers/339107/32 "2006-01-09T18:43:47Z")
> [@Drum God](#): > > On a cruise vacation in the Caribbean, one of our ports (Grand Cayman) was a “tendered” port. Two of the lifeboats were used as passenger tenders. One of the tenders was the lifeboat that me and my family were assigned to. I always wondered what we were to do if the ship were in distress while my lifeboat was running taxi duty. I would go to my muster station, but no lifeboat would be there. :eek: Drum God… no problem at all. Tendering is only done within a VERY close distance to shore… at Georgetown, Grand Cayman it probaby takes the tender less than 10 minutes to get to the dock. That same tender, under emergency circumstances, would return to get you in a VERY short time. You would be directed to a new muster station on Deck One (or whatever deck you use to embark the tender) rather than up on Deck X where the lifeboat was stored. Did you get to see Stingray City? It’s awesome. ---
**Author:** ![UncleBeer](https://avatars.discourse-cdn.com/v4/letter/u/977dab/32.png) [@UncleBeer](https://boards.straightdope.com/u/UncleBeer)\ **Post date:** [January 9, 2006, 6:54pm UTC](https://boards.straightdope.com/t/how-does-the-navy-clean-the-bottom-of-aircraft-carriers/339107/33 "2006-01-09T18:54:33Z")
> [@jrfranchi](#): > > :smack: > I am confusing terminology. I was thinking of the slipways as drydocks. I forgot they are are not the same thing. D’oh. > > Sorry > Jim If we can sort out (or just ignore for the moment) the issues of jargon, submarines are constructed in this fashion, too. I’ve seen several of them under construction at Electric Boat in Groton. But as noted, laying the keel is a totally separate thing from getting an already built ship out of the water. Electric Boat calls their hull construction areas “graving docks.” Here’s a [photo of a Virginia Class (SSN757 - Alexandria) in dry dock](http://www.gdeb.com/capabilities/). Which actually looks like a “spillway” to me. The hull looks like it is held aloft over a paved surface rather than water. ---
**Author:** ![ElvisL1ves](https://avatars.discourse-cdn.com/v4/letter/e/5daacb/32.png) [@ElvisL1ves](https://boards.straightdope.com/u/ElvisL1ves)\ **Post date:** [January 9, 2006, 7:15pm UTC](https://boards.straightdope.com/t/how-does-the-navy-clean-the-bottom-of-aircraft-carriers/339107/34 "2006-01-09T19:15:32Z")
> [@Mangetout](#): > > Some ships are built above water and launched by sliding them down a slipway into the water. Even quite large ships have been launched this way. [That method is dying or dead already, though](http://www.gdbiw.com/news_and_events/press_releases/2001_archive/2001_05_25_01.htm). US Navy destroyers are all built in drydocks and just floated out now - it’s easier and much safer, but much less of a spectacle. ---
**Author:** ![UncleRojelio](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/unclerojelio/32/3160_2.png) [@UncleRojelio](https://boards.straightdope.com/u/UncleRojelio)\ **Post date:** [January 9, 2006, 7:26pm UTC](https://boards.straightdope.com/t/how-does-the-navy-clean-the-bottom-of-aircraft-carriers/339107/35 "2006-01-09T19:26:43Z")
Strangely enough, when I went home for lunch today, _Modern Marvels_ was on. In this episode, they were showing the construction of one of the Navy’s newest Arleigh Burke class destroyers. It was being built at Bath Iron Works. They showed the old inclined slipways and mentioned that they don’t use them anymore because sometimes ships capsize when launched this way. :eek: The modern marvel way to do it is to build the ship on shore and then trolley it out onto a floating drydock. The drydock is then floated out into the Kennebunk river and lowered to allow the destroyer to float free. The difficult river navigation out to the Atlantic then begins. ---
**Author:** ![Drum\_God](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/drum_god/32/44_2.png) [@Drum\_God](https://boards.straightdope.com/u/Drum_God)\ **Post date:** [January 9, 2006, 8:00pm UTC](https://boards.straightdope.com/t/how-does-the-navy-clean-the-bottom-of-aircraft-carriers/339107/36 "2006-01-09T20:00:50Z")
> [@Gringo\_Miami](#): > > Drum God… no problem at all. Tendering is only done within a VERY close distance to shore… at Georgetown, Grand Cayman it probaby takes the tender less than 10 minutes to get to the dock. That same tender, under emergency circumstances, would return to get you in a VERY short time. You would be directed to a new muster station on Deck One (or whatever deck you use to embark the tender) rather than up on Deck X where the lifeboat was stored. > > Did you get to see Stingray City? It’s awesome. Yes, the anchorage was quite close to Georgetown. We boarded the tender down on deck one, just above the water line. That was the only time in the trip that I started to get a bit seasick, as we were crammed into a boat that was bobbing like a cork next to a MUCH bigger boat. I tried to imagine what it would be like in a true emergency, but, as I understand it, the lifeboat wouldn’t be in the water, but still hanging on the davits. During the initial muster drill on the first day, we were all standing under the lifeboat at our muster station. We were to stand shoulder to shoulder, taking up no more area than the space directly under the boat. The lifeboat officer was having trouble getting cooperation from one of the passengers. The officer thumped (his own) chest and said “I know where my seat is on that lifeboat!! Do you have a seat!!!” Got my attention. :eek: ---
**Author:** ![Drum\_God](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/drum_god/32/44_2.png) [@Drum\_God](https://boards.straightdope.com/u/Drum_God)\ **Post date:** [January 9, 2006, 8:16pm UTC](https://boards.straightdope.com/t/how-does-the-navy-clean-the-bottom-of-aircraft-carriers/339107/37 "2006-01-09T20:16:51Z")
> [@Gringo\_Miami](#): > > Did you get to see Stingray City? It’s awesome. No, we missed it. I’ve heard that it is spectacular and, if we ever go again, I’ll make sure it’s on our itinerary. Instead, we enjoyed relaxing on the beach. We were astounded at the prospect of walking into water you could see through. Here in Texas, the seawater is so murky you can’t see your feet even if you’re just ankle deep. The water was so clear it was breathtaking. ---
**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\ **Post date:** [January 10, 2006, 12:30am UTC](https://boards.straightdope.com/t/how-does-the-navy-clean-the-bottom-of-aircraft-carriers/339107/38 "2006-01-10T00:30:20Z")
> [@Gringo\_Miami](#): > > ROTFLMAO… that is too funny! Please tell me it’s Photoshop and not real… :eek: There is much dispute about it, because all of the images available of the ship contain jpeg artifacts that some people have argued are remnants of photoshop tweaking, however, there was a thread about it here a while back and someone or other looked it up in the international registry; there is indeed a ship of that name, so it seems reasonable to accept that this is it. ---
**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\ **Post date:** [January 10, 2006, 12:33am UTC](https://boards.straightdope.com/t/how-does-the-navy-clean-the-bottom-of-aircraft-carriers/339107/39 "2006-01-10T00:33:28Z")
> [@ElvisL1ves](#): > > [That method is dying or dead already, though](http://www.gdbiw.com/news_and_events/press_releases/2001_archive/2001_05_25_01.htm). US Navy destroyers are all built in drydocks and just floated out now - it’s easier and much safer, but much less of a spectacle. That it is a dead or dying method I certainly wouldn’t dispute; the last one I recall witnessing was actually a sideways slide into the water and it created a massive wave that swamped the dock one the opposite side (where there were standing lots of spectators). Don’t remember the name of the ship though. ---
**Author:** ![Scruloose](https://avatars.discourse-cdn.com/v4/letter/s/e68b1a/32.png) [@Scruloose](https://boards.straightdope.com/u/Scruloose)\ **Post date:** [January 10, 2006, 12:52am UTC](https://boards.straightdope.com/t/how-does-the-navy-clean-the-bottom-of-aircraft-carriers/339107/40 "2006-01-10T00:52:56Z")
> [@Mangetout](#): > > There is much dispute about it, because all of the images available of the ship contain jpeg artifacts that some people have argued are remnants of photoshop tweaking, however, there was a thread about it here a while back and someone or other looked it up in the international registry; there is indeed a ship of that name, so it seems reasonable to accept that this is it. I just checked the _Equasis_ shipping database. There is indeed a Hong Kong flagged crude oil carrier named **Titan Uranus**. The IMO number matches as well. [Previous page](https://boards.straightdope.com/t/how-does-the-navy-clean-the-bottom-of-aircraft-carriers/339107.md?page=1) [Next page](https://boards.straightdope.com/t/how-does-the-navy-clean-the-bottom-of-aircraft-carriers/339107.md?page=3)