Why Are The Battleship's Propellers All Different?

[@jimgraves4197]

This dry docking is teaching us so much more about Battleship New Jersey in terms of how well she is coping with sitting in the Delaware River for 25 years. Modern coatings will help the ship reach its 100th birthday and then some more. Keep up the good work.

[@rileypittmon]

I wish the Texas crew would've done the same and give us a little more in depth look at what and why. Ryan and New Jersey crew are killing it with the coverage they are providing.

[@TheEDFLegacy]

As someone who is a volunteer on a museum ship that is 117 years old, I can't stress enough the importance of protecting the hall. We've been lucky that the ship has been kept in such good shape, but it's quite obvious that her hull will need to be replaced, which is what is going to happen in a couple of years.

[@daytona1073]

All of it? The whole thing? Reminds me of the old myth (Greek or Roman) of an important wooden ship... It was preserved, but over time individual planks would rot, and need to be replaced... I guess paint or stain had not been invented yet... Did anyone know about teak? How about cedar? So, after a long enough time, ALL the planks get replaced... The question then is, is this ship still original, or is it a replica? Apologies for this being so long... I need sleep...

[@TheEDFLegacy]

@daytona1073 I've heard of it. You're speaking of the Ship of Theseus Paradox. It's something that constantly goes through my mind while I'm doing work on my ship. Wherever I can do non-invasive modifications to the ship, I will do so. Wherever I have to, I do the absolute minimum damage to the ship itself, even resorting to zip ties instead of screws when mounting new conduit or cabling as an electrician. Recently I've been running a new ethernet cable, and I ran it through a rivet hole that I found, which will later be covered up by decking (the carpets and wood underneath were in very poor condition, unfortunately). The good news in my particular ship's case is that the central part of the ship has been mostly kept dry, so much of the original wood and steel are still in place, including some of the fittings. Unfortunately, that was not the case and the outer areas where water was able to get in. The hole itself obviously there's not much we can do, but thankfully, it's been kept in decent condition, all things considered. We're also lucky that its new home is an actual historic dry dock, so we won't need to ever move it again, even if we need to drain it to do work on the hull.

[@richardm.6515]

@@TheEDFLegacywhich ship is 117 years old? Olympia?

[@thejerseyj5479]

I was there on the 6th of April and can tell you that the pictures can't do justice to how imposing the screws and rudders are. It is shocking to say the least. After the tour I saw Ryan and had a chance to thank him personally for all his efforts towards the upkeep and preservation of this magnificent battleship.

[@ddegn]

Very cool. I envy you. Thanks for sharing your experience with us.

[@snuffle2269]

Thank you for thanking him. I wonder if he has boys.

[@davecaron1213]

You mentioned the maneuverability of the Iowa class. One of my uncles was signalman on Missouri. He told me on their shakedown cruise he was up on the signal bridge when the captain (a former cruiser captain) brought the ship up to flank speed and then ordered full left or right (I do not remember which) rudder. He said the bow lifted up; she leaned over, and entered the turn just like a PT Boat. Forty thousand tons turning on a dime!

[@TheEDFLegacy]

Hot damn! Kind of reminding me of the Battleship movie perhaps there's more truth to it than I originally thought. 😳

[@alanjameson8664]

Gee.

[@zeedub8560]

The Iowas could turn inside some of their escorting destroyers. There was at least one incident where a destroyer captain apparently didn't believe this and nearly caused a collision (I read about this many years ago, don't remember the details).

[@steeltrap3800]

~58,000t at full load which makes it all the more impressive. Must've been something to see.

[@rdfox76]

@@TheEDFLegacy If they tried the "anchor turn" thing from that movie, they'd just rip the anchor clean off by snapping the chain.

[@nhenslin]

In Navy parlance we just called them screws but It's always impressive seeing them out of the water. Only then do you realize how powerful these ships were compared to most civilian ships and what it takes to propel a ship this size to 30 plus knots. I served on a gearing class destroyer and she could do 35 knots if the captain wanted to open her up but that speed was expensive in terms of fuel consumption. You can go fast or you can go far but not both !

[@brucenadams1]

When the USS-Brush DD-745 was in drydock, I noticed that the rudders were not directly behind the center of the two 14 foot propellers. They were inset about a foot. I looked at the prints and, sure enough, that was the way the rudders were designed. I was told that the shaft could be removed without disturbing the rudders if repairs were needed. The New Jersey may use the same design. When you get a chance, take a quick look.

[@eknapp49]

One of my favorite “screws” versus “propeller” stories supposedly happened to the Royal Air Force. During the interwar years and in the early years of World War II the RAF’s official name for a propeller was an “air screw.” The story goes that an RAF bomber command base ordered a replacement air screw for one of their planes. What arrived was a replacement air crew for the plane. The RAF looked at this and realized that was too easy a mistake to make and the designation “propeller” was made official.

[@kimmer6]

I worked on reactor feed pumps on the USS Enterprise CVN 65 at Alameda in the early 1980's. One of the engine rooms had a sign that said ''Longest shaft, best screw''. I used to know the length of the shaft but forgot the details. I recall that an engineer onboard said that the propeller shaft wrapped up in torsion 3-1/4 turns between the gearbox and propeller when the ship was at flank speed. That's a lot. The engine room crew always refereed to them as screws.

[@phildyer197]

because screws are what they are

[@EricLetourneau-xq2dc]

I wonder how many RPMs the shafts spun, on USS Enterprise at full speed ?

[@kimmer6]

@@EricLetourneau-xq2dc I heard 120 rpm max.

[@petersplat6164]

3-1/4 turns on a massive drive shaft like that is a lot of stored energy and an enormous stress. I don't have to tell that to anybody here. Whew.

[@victorm56]

@@EricLetourneau-xq2dc hopefully no answers that, max. shaft RPM was and still is classified.

[@Train115]

When Massachusetts ends up going into dry dock eventually, not that its planned right now at all, PLEASE visit her. That video would be an amazing comparison between the two.

[@cruisinguy6024]

I think it’s a given Ryan would help them with what he’s learned and visit the dry dock

[@danam0228]

I love Big Mamie

[@dieselyeti]

The Massachusetts was drydocked in 1998-1999. I doubt it'd go in again anytime soon.

[@danam0228]

@@dieselyeti probably not, but it's deck is a mess

[@cruisinguy6024]

@@dieselyeti that means they’re due within ten years or so - ideally sooner rather than later. If I remember right they’d never dry docked her since her decommissioning and had significant hull issues that required major repairs. I’m sure they want to avoid a repeat of that.

[@Not.The.Avg.Smitty]

Ohhhh the exact area I needed to see for my epic battleship build! Thank you so much Battleship New Jersey!

[@jpjh8844]

Honestly I love this comment, don't know if your talking about a physical scale model, or a virtual (gamer, programer, etc) scale model.

[@Not.The.Avg.Smitty]

@@jpjh8844 I make artwork, it has functional 16" cannons .177 bbs happen to fit in case potatoes don't do it.😉 You can see the Sherman Tank stainless steel build shoot potatoes in completed artwork. The ship is 36" I had to sacrifice the aft end for space but it can be seen.

[@Not.The.Avg.Smitty]

@aaronvockley5448 thanks

[@TheEDFLegacy]

​@Not.The.Avg.Smitty Plot Twist: It's a 1:1 model, and you are secretly plotting to sink a deepwater navy. 😅 j/k

[@Not.The.Avg.Smitty]

@@TheEDFLegacy shhhhhh, don't want others to know who has been hoarding steel.🤫

[@rdfox76]

For those who are curious, the reason for the vibration problems on the fast BBs was apparently due to unanticipated interactions between the propellers and the skegs. Each time one propeller blade passed behind the skeg, the reduction in water for it to bite into resulted in a brief reduction in the power generated, making it more pulsed than previous ships. As it turned out, at certain speeds, this series of pulses would match the resonant frequency of the propeller shafts, causing the whole things to start vibrating forward and aft with the pulses in the power. On North Carolina, during her initial speed trials, apparently, the inboard shafts were vibrating almost *two feet* fore-and-aft before the chief engineer aborted the run out of fear that it would rip either a thrust block or a reduction gear set loose from its mountings. There really wasn't any perfect solution to this; any sort of screw would generate the same sort of power pulses, which would hit the resonant frequency at *some* speed. The final fix was to essentially select a set of screws that would hit the resonant frequency at a speed *not* in a range of common fleet speeds (either cruising or battle speeds), and then just avoid that speed as much as possible--either staying below it, or just powering through it as quick as you could until you got out of the problematic shaft RPM range. Similar problematic vibrations, albeit with a very different cause, were also found in the Atlanta class light cruisers; on Atlanta herself, during the twelve-hour top speed run in sea trials, cans of paint stored in the ship's fantail area were apparently vibrated to destruction(!), so this wasn't unique to the fast battleships. (Apparently, SS Normandie, with a somewhat similar hull form to the US fast battleships, also suffered from similar resonant vibrations during her early years.)

[@jetdriver]

Do you have a source for this information?

[@dougalexander5871]

I’m reminded of the issue of vibration for an aircraft transitioning to supersonic speed. I wonder if the physics are in any way similar?

[@workingguy-OU812]

Thank you so much for writing this out. It makes sense.

[@rdfox76]

@@jetdriver I don't have a convenient link to it at the moment (it's on my currently-bricked laptop's hard drive), but it's from the official report on Showboat's vibration issues from 1944 or thereabouts, as found via some digging with Google, combined with some information from Norman Friedman's US Battleships: An Illustrated Design History. (Specifically, the stuff about just avoiding the problematic speed ranges and about Atlanta's vibration issues are from Friedman; the rest is from the Navy report.) There's also a little of my own personal interpretation in there (exactly *why* the chief engineer called off the top speed runs--it wasn't recorded beyond "to avoid damaging the machinery," but that's pretty simple to figure out!), and trying to summarize and boil down the more technical language to something a little more digestible in a less-technical forum such as this. I'll note that the report also said that the reason nobody had anticipated this as being a potential problem is that no previous US Navy ship had ever experienced *longitudinal* (i.e., fore-and-aft) resonant vibration of the propeller shafts before; all previous resonant vibrations had been either side-to-side or up-and-down (or some combination of those two). As a result, while the ship was designed to damp out *those* sorts of vibrations well, nobody had ever considered that there might be a need for something to damp out longitudinal vibrations. One solution that was at least tried (it's not clear if it became a permanent solution) was to install wood blocks as spacers between the shaft itself and the sensitive parts of the machinery, to act as shock absorbers/cushions much like the wood blocks in Jersey's keel blocks right now.

[@johnparrott4689]

Good info, thank you! I recall reading about ‘North Carolina’’s issues that you described, years ago

[@madredrobin2620]

I would love to go to see this beauty in dry dock but unfortunately living in the UK makes that very difficult

[@LarryStone-d2e]

Ryan as a Naval architect I agree with you that vibration issues occurred in the USS North Carolina but what you do not address is the cavitation issue which can result in vibration not to mention the loss of propulsive efficiency. The inboard props are operating in the wake of the outboard props. This means that the inboard props will see the onset of severe cavitation at relative slow speeds resulting in vibration and loss of efficiency. This condition is magnified as the vessel's speed increase. One solution, at the time of the ship's design was to increase the expanded area ratio of the propellor. This is accomplished by increasing the number of blades and reducing the diameter of the propellor. Before the advent of high speed computers propellor design was a black art governed by experimentation and trial and error as demonstrated by the year long sea trials of USS North Carolina.

[@dennish9519]

The entire time that I was watching and listening to this video I could not help but to look at the shaping of the haul around the inboard props and think, "The size and tooling needed to shape that plate steel into that shape had to be huge!" and then there is the skill by the ship builders.

[@timbonjovi]

I am amazed at the amount of knowledge that Ryan has . I've been into warships my entire life and I thought I knew alot until I started watching Ryan's videos.

[@thereissomecoolstuff]

He has a 800’ library.

[@williamriley-le9zo]

Or you could say, " He has a boatload of knowledge"... LOL

[@oldtugs]

Yeah, it's 887 feet long, 108 feet wide and an inch deep

[@markw756]

Ryan's office library is incredible. He allowed me to sit in his office and peruse some of the hundreds of books and documents. He is an excellent educator and shares his ship enthusiastically. Get a private tour with him.

[@zackakai5173]

Ditto. I've been fascinated with this subject since I was about nine (I'm now in my 30s), and I still learn cool new shit every time I watch one of these videos.

[@richardgreen1383]

I saw the picture and didn't look close, so I thought "OK, two five blade and two four blade, that's different", not noticing the counter pitch of the blades. Learning a lot from these episodes. Thank You.

[@christineshotton824]

These videos since the dry-docking of USS New Jersey are fascinating. We can all go to the museum ships and tour the sections inside or above the waterline, but these dry-dock vids are a once in a generation experience. 👍👍

[@KPen3750]

Funnily enough, I was looking into this, Massachusetts BB-59 started with 4 bladed props on all her shafts, and ended her career with 5 bladed outboard props and 3-bladed inboard props. So yeah, a lot of changes

[@donwayne1357]

Now, just hold on a minute there.

[@dieselyeti]

I saw the drydock photos from her maintenance in 1999. I found that odd too, assuming she'd have 4 and 5 blade props.

[@scottspilis1940]

I think Friedman's book on U.S.Battleships has an extensive discussion on on the various propeller combinations used to reduce vibrations on the fast battleships. A lot of trial and error testing and it was not consistent from ship to ship, even those in the same class. I think the Iowa's were consistent, and eventually the North Carolina's but the South Dakota's were all over.

[@garywagner2466]

Let’s count how many people argue about “screws” versus “propellers.” Must be 500 by now. You must be so proud! Thanks Ryan for another fascinating video.

[@mikezimmermann89]

I say they’re “propellers” when you’re writing a report (especially an engineering report); but, they’re “screws” when you’re talking about them… especially with fellow sailors.

[@zackakai5173]

Jesus, honestly. As pointless arguments on the internet go, this one is admittedly pretty harmless, but that doesn't make it less pointless. I would argue the full technical term would be "screw propeller" (i.e. a device based on the principle of the Archimedes screw which is used to propel some kind of vessel, either vertically or horizontally), but even that's still just semantics. At the end of the day, words mean whatever the people who use them use them to mean (descriptivism > prescriptivism). And since people regularly use both terms without ambiguity, both terms are perfectly valid.

[@justaskin8523]

I haven't seen a lot of "arguing" here in the two weeks that have passed between your post and mine. Mostly everybody is just sharing stories and building camaraderie. That's a W, if you ask me.

[@jamesretired5979]

I as a retired fitter would like you to give us a more blow by blow of the work as it is done.

[@KateWandless]

Another ex fitter here, have great memories working in dock bottoms playing with huge props and falling over inside bow thruster tunnels

[@DavidSmith-cx8dg]

A really informative video , so well explained by Ryan . The engineering skills needed to keep those shafts turning through those sort of lengths without shaking the ship to bits are extremely high and it's not surprising they had problems finding the best combination of props . It's a problem with new ships even today despite all the computers used to design them . I did think the propellers looked painted from earlier videos and it obviously makes sense for a museum ship . I wouldn't care to think of the strain on them and the shafts if they touched the bottom regularly . I must say for the last docking , thirty years ago has resulted in New Jersey looking in an excellent state of preservation below the waterline , they did a great job for all the visitors who come to see her .

[@Train115]

The South Dakota-Class was built with all 4 bladed propellers, with Indiana swapping to 5 bladed outboards and 4 bladed inboards and Massachusetts swapping to 5 bladed outboards with 3 bladed inboards. Their propellers were almost completely lined up with each other but the inboard were slightly forward more, unlike the Iowas. Also unlike the Iowas the skegs are on the outboard shafts instead of the inboard.

[@TheJazsa80]

The South Dakotas were designed different to the Iowas because they were a different design. Despite the design differences both ships could travel backwards if they reversed the rotation of their propellors.

[@ralfie8801]

If there were 5 frogmen around each outboard propeller, there would be 20 more fins in the water.

[@dieselyeti]

I don't know about the other SoDaks but the Massachusetts has 3 blade props inboard and 5 blades outboard.

[@Train115]

@@dieselyeti Massachusetts was built with four 4 bladed props, but later changed to 5-blade outboard and 3-blade inboard. I dont remember if the other SoDaks followed suite, but thanks for catching that.

[@mm3mm3]

Awesome shots tonight! Great job Ryan and Libby!!!

[@ManuelPerez-ip4bb]

Different blade numbers also helps with resinence displaysment.

[@MaleObliviousness]

I'd like to take a moment to stop and appreciate the joke at 6:10. The Hollings (or Holland) tunnel, the tunnel that has the most traffic of any tunnel in New Jersey.

[@heathbrown4243]

I think it’s amazing to learn about the ship even out of the water. Some of the most interesting things are underwater where we don’t normally see it. I went to Battleship Texas BB-35 when she was in dry dock it was amazing then.

[@CAPNMAC82]

There was an argument about using 5-blade screws on the outboard, as those would have been smaller diameter, which meant less issues of "overhang" if alongside a pier or quay. However, as finally realized, the shaft positions meant that the 4 blade screw would be clear of the inboard hull dimension. In tests at the Towing Tank, the 4 blade screws helped give better turning response when put aback.

[@heuhen]

Massachusetts BB-59 started with 4 bladed props on all her shafts, and ended her career with 5 bladed outboard props and 3-bladed inboard props.

[@lindsaymarshall4734]

We always referred to them as “screws” during my active duty service in the Navy 1967-69 on the USS Wiltsie DD-716 and the New Jersey.

[@edwardmeade]

In re the centerline bulkhead. In the early hours of 29 May 1914, the RMS Empress of Ireland was T-boned in St. Lawrence River outbound from Quebec City, QC. by the Norwegian collier Storstad near the town of Rimouski. The Empress had side by side propulsion spaces in a 4x4 arrangement. The Storstad hit her at the bulkhead dividing the stbd boiler room and the stbd engine room. Counter flooding was attempted but couldn't keep up with the inflow from the damage. The ship capsized just a little over 14 minutes after the initial collision. 1,012 of the 1,477 passengers and crew perished, most not having time to even get to the lifeboats. This shocked the naval architecture community and the centerline watertight bulkhead pretty much vanished.

[@jamesgascoyne.7494]

Well that's great news. You said in an earlier video you were thinking of keeping the screws. Now saying they will be repainted that means they are. Brilliant! It's like looking at a cow with only 3 legs it she hasn't got her screws on. That's really fantastic news. So pleased.

[@davewitter6565]

This is fascinating. I had no idea the elegant design of the propulsion system.

[@mikehenson819]

Screws or props is what I referred to them when I was onboard the USS Indy CV-62 back in the late 70s.

[@jimkemp3985]

Screws, of course. Back in the 80's on a destroyer we had a CO who had been Ops on an Iowa class. He told us about the "tunnel", and some unique maneuvering capabilities (and issues) it enabled, especially going astern. What a beautiful ship she is. Thank you, Ryan.

[@Seiskid]

Very smart hull shape. Stunning to see this magnificent ship out of the water.

[@allieversaid]

Great work Ryan keeping our Battleship New Jersey alive

[@thegenrl]

very interested in details of the coatings you will be using for the hull and propellers. subscribed

[@anthonydecroce8146]

While the ship is still out of the water, maybe a video could be done about the cutlass bearings.

[@kriley9386]

Dis-similar metal corrosion when sitting still. Yes! Brass props and steel hull. Good catch.

[@888jackflash]

One of the more fascinating clips on BB-62 I have seen

[@paulhill182]

Love this view and the explanation of why the props are different.

[@pauld6967]

I'm a "propellers are on airplanes, screws are on ships" guy.

[@skyraider87]

Props on planes, screws on ships

[@AmraphelofShinar]

My father sailed on Wind-class icebreakers in the USCG, and he always called these "screws".

[@glennac]

Ryan, I know you’ve visited the propeller shafts several times before. But it would be fascinating to see you go back as far as you could inside the skegs. Then, point out what spot that was on the outside now that she’s out of the water.

[@Springer_maniac]

Thanks for clearing that up Ryan, you do a great job of explaining everything, the Museum is very lucky to have you!👍

[@briancorreia2923]

The way I’ve understood propellers is that every additional blade over two is less efficient. But the pulsing against the hull of a ship is more pronounced for a given thrust with fewer blades. (3 blades= high top speed while 4 blades = low speed power and smoother operation.)

[@455buick6]

I think that used to be the case earlier but as technology has advanced that's no longer so

[@poowg2657]

You mentioned that the props were changed out to mitigate high speed induced vibration. It would be interesting to use modern computer generated fluid dynamics to study the harmonics of the equipment, proppellers and flow of seawater. Something similar was recently done to convert Union Pacific Big Boy locomotive 4014 to burn oil instead of coal. During WWII this was tried but found to be a failure no matter where the burners were placed in the firebox. After a study using computational fluid dynamics a solution was found and 4014 is happily plying the rails today. It would be interesting to see such a study on the Iowas' vibration problems. This type of study could be done on any ship where pertinent specs are available. Mr. Drachinifel is an engineer, perhaps he would know the proper people to conduct such a study. Cool video, thanks much!

[@pault151]

We had a "fossil-fueled" electric generating power plant series in California that were designed to run on either oil or natural gas because of some market issues. These were designed and built in the 1950's and 1960's IIRC. There were different sets of burners and optimal locations for each that had to be swapped out to change fuels, and the heating profile within the boiler was also different with different tubes receiving more or less heat depending on the fueling. It made for a complex design, and that was just from a liquid to a gas fuel - coal would have made it even more different.

[@davidfreiboth1360]

At the Washington State Ferry system (back when I was a deckhand anyway) we typically refered to the propeller as a propeller or a prop. I was familiar with the term wheel but I don't recall hearing it in conversational use.

[@donsimon4419]

I remember while I was aboard USS Bainbridge (CGN 25) in 1986 doing Division Tactics (DIVTACS) exercises with USS Missouri (BB 63) in the Mediterranean Sea. Trust me, she was no slouch when it came to speed or maneuverability! The exercise was great ship handling training for both ships.

[@joelmacdonald6994]

Funny enough, I saw the difference in the first picture in dry dock. I didn’t even bother asking why, I just knew there’d be a video to explain. Thanks Ryan for confirming of what I’d had 99.9% certainty; I just knew this would be explained.

[@jcip1]

Another interesting video…thanks

[@stevendaugherty7590]

Ryan, very interesting & informative video. Thanks! My father served in the US Navy in the Pacific Theater in WWII and he told me (before he passed away) that he always felt safer when one of the Iowa class battleships were in sight of his ship (USS Pasadena, CL65) due to their enormous firepower. So, I've had an interest in Iowa class ships (and most other Navy ships in WW2 era) since I was a boy.

[@henriktw4051]

Thank you for answering my question Ryan. I never would have thought that all four propellers were different, that's really interesting. I think I need to get a book on how exactly propellers work on ships, how they move the water and what differences there are. You really learn something new with every video!

[@bac-up6758]

Fantastic backdrop bro!! Bravo!

[@MK0272]

Were the propellers interchangeable between the various Iowa class ships (or even with other classes of ships) or were they specific to that ship?

[@Kholdstare0503]

I can’t imagine how excited ryan must be during all this! If it were me I’d be busting at the seams too!

[@mtm101designs9]

Thanks for a great explanation. I had no idea about the Holland tunnel or the configuration of the propellers and shafts.

[@dk2614]

I haven't seen a battleship screws but I have seen the screws on a Replenishment ship in rough seas from the fantail of an LPH. Pretty cool stuff. It's absolutely amazing how big ships are and everything on them.

[@snuffle2269]

I'm sitting in Europe watching Battleship New Jersey video after video. Very interesting subjects you picked for presentation.

[@naturecoastprepping2487]

You can export the program and post the file . I’ve shared my chirp plugs w others & it works . Great idea and video today . I’ve been following your repeater board you’ve been making .

[@steveghazarian]

This is one of the most interesting videos you’ve posted. Thanks so much 👏

[@murraystewartj]

Thanks, Ryan. Am I the only one who wishes Drachinifel could be there for a REAL Drydock? That would be epic.

[@johngaltline9933]

check the video "Live Drydock from a Drydock during Drydocking - Aboard USS New Jersey"

[@rich7934]

He was at the USS Texas while in Drydock and did at least 2 videos with the USS Texas Currator and you had to go to the their youtube video to see the rest.

[@julesjames593]

I'm having so much pleasure watching this! Thank you. Assuming I can look forward to a couple "All About Anchors!" videos?

[@roneified4405]

Great video! Thanks for answering my question from the comments section!!!

[@leafflowerbud4345]

Really loving your series on the dry dock!

[@unclerojelio6320]

I knew Ryan wouldn’t disappoint.

[@DanFink-jm8md]

When I was aboard New Jersey (89-91) we (and the yard birds at the Long Beach Naval Shipyard) referred to the area between the skegs as the ballroom, not the Holland tunnel, same for the Missouri. When you stand between the skegs it is as if you are in a huge ballroom, hence the name. Regarding the placement of the skegs vis-a-vis the rudders, this allowed us to employ a unique tactic to stop the ship in its own length from a standard bell (15 knots.) We called it "closing the barn doors." As an officer of the deck, I practiced it several times, thankfully, we never had to use it for its intended purpose: avoiding a collision or grounding if the ship was "in extremis." From a standard bell, the commands were: "Rudder amidships" - the helmsman would then turn the wheel to centerline the rudders. "Lee helm, all back full" - The lee helmsman would cycle the EOT (engine order telegraph) from Ahead Standard to Back Full three times, then leave it at Back Full. "Indicate 999 for maneuvering combinations." - The Lee Helmsman would turn the dials used to indicate the desired propeller RPM from whatever had been selected to "999", indicating no particular speed and telling the throttlemen to both close the ahead throttles and open the astern throttles all the way. "After steering take control, close the barn doors." - The two after steering watchstanders would take individual control of each rudder. The starboard rudder would be thrown over to left full and the port rudder would be thrown over to right full, effectively pointing each rudder at the other across the ballroom. This turned the ballroom and the rudders into a huge drag chute, slowing the ship dramatically. When we practiced this, we would have a boatswain's mate at the bullnose throw a block of wood overboard and track how far down the length of the ship that block went before the ship was dead in the water. Invariably, it never made it past the stern. If nothing else, it was a fun way to spend a few hours underway and practice our ship handling skills, and it gave us options if we were ever dumb enough to put the ship in imminent danger...

[@Cirux321]

Should spray the screws down again and collect some water off them. Then bottle it, seal it and auction it off labeled 'Battleship New Jersey "Prop Wash" 😅

[@dougalexander5871]

That’s a BRILLIANT idea!

[@trohlack5150]

I really enjoyed this one for the very complex design considerations.

[@Whiskey11Gaming]

Ooooo!!! Tactical Diameter discussion! HAWT. Would be cool to see the "Barn Door" emergency stop demonstrated while in dry dock, but I bet you can't because of the dry dock rules. Would still be cool to see!

[@kiereluurs1243]

Impressive to see how precisely the ship landed on its blocks.

[@logcrouch]

Well Ryan... on this video I have to give you props!

[@gabrielchiodo285]

Awesome, I am always fascinated with the propellers of ship's.

[@Anonymous-uno]

They are works of art. Since you have one on display already, I would love to see a museum do a mock up above ground of the 4 propellers. Edited after watching another video.

[@SMOBY44]

Ryan, you should do a one time dry dock tour where the people on the tour get to watch you film an episode, and if they wish be shown in the episode.

[@EdwardKilner]

Excellent narration. Thank you.

[@bobgasm1471]

Currently read the book Battleship at War, about the USS Washington, it seems that during her shakedown they were changing the props on the average of once a week trying to find the right combination.

[@clemsonbloke]

Ryan, I am from South Carolina so as you know we have the USS Yorktown and USS Laffey. I really hadn't thought about it but the New Jersey is a bigger ship than the Yorktown, I didn't think the battleships were as big as a Carrier. Now, I know the Modern Carriers are bigger than anything but those old Essex class is a smaller ship. New Jersey is a big ship, especially how old she is too.

[@mechanicmike2858]

So Fascinating thanks for answering my question !!!

[@DigitalDiabloUK]

I feel like all my questions from the previous video have been answered 😂👍👍❤

[@paulpeterson5214]

----- It seems those slide ruler engineers knew what the heck they were doing when they built her.

[@tomhenry897]

Seen pictures of their office? A high room full of guys working

[@mattbartley2843]

It's good to see this dry docking happen. One of the last ships I've visited is the Lane Victory in San Pedro, CA. They used to actually take her out to sea occasionally, but there was a breakdown in the boilers. I was told it's repairable now, but the ship now should go into drydock maintenance, but that'll be so ridiculously expensive it'll never happen without a huge donation. At least there's some hope. One of the other signature ships in the area, the last one I've visited, is RMS Queen Mary in Long Beach. As spectacular as she is, will probably never go anywhere ever again. As I'm sure you know, the other signature ship in the area is your sister ship USS Iowa (BB-61). I've visited once since she arrived, and driven by countless times. I still regret not being able to sail out there when it was anchored offshore after being towed from mothballs, but the weather sucked those days.

[@thestrum71]

Ryan has the coolest job on the planet....

[@markciocco2509]

Great explanation. A number of things mentioned I did not know. Is there a reason why videos of the work on the ship are not being made?

[@nicholaspayne349]

Man I really could use a big long format video about some of this drydock stuff. 8 minutes just barely wets my whistle

[@RetiredEE]

Ideally Ryan can get dedicated 4K resolution video of a full walk-around while she's in Drydock, and sell copies to generate more funding. Same for everything else once back at the museum site. I'd think serious modelers wouldn't have a problem getting a set of vids from all angles and with ideal lighting. Directly underneath, get some floodlights and take footage at night, gets things out of the shadows. Mad props for another great vid 👍

[@rogergoodwin5533]

Amazing information.

[@garymartin6987]

The USS Coral Sea (CV-43) Also had 2 4 bladed screws and 2 5 bladed screws. This was done to make turn counting more difficult (she sounded like a friggin' washing machine).

[@SteamCrane]

Good point!

[@icare7151]

❤the channel. Awesome data.

[@brianpesci]

Great explanation of the hydrodynamics.

[@GregMcCoy]

Ryan, are the shaft bearings solid bearings such as bronze or babitt, or ball/roller bearings?

[@francismccabe3265]

Babbitt split shell bearings. They can fail/run without lubrication and sometimes be scraped and put back into service. Easily changed in place. Split race ball and roller bearings can be produced, but are much more complex. When they fail, they can ruin the shaft and/or housing.

[@JJLewin1]

Beautiful battleship, always wanted to take a look around one

[@traderalex1]

I always understood that that the hull bottoms of Iowa class BB's and Midway Class CV's are nearly identical.

[@paulreuter7763]

same setup on USS Midway CV 41

[@stevencovington4715]

1 Screw Crew CV41 85-87.

[@paulreuter7763]

@@stevencovington4715 70-80 m dIV. MATERIAL OFFICER

[@JetLagRecords]

Battleship New Jersey, Subscribed because your videos always make me smile!

[@DesertRat332]

When I was on the USS Missouri (BB-63) for two weeks in the early 90s I was told that the 4 blades were the power screws and the 5 blades were the speed screws. I was also told the 4 blades acted as booster pumps for the 5 blades. I don't know if either is true. Interesting how the two inboards are right in front of the rudders to make them more effective.

[@johnjones5354]

Fascinating explanation. Thank you.

[@ewathoughts8476]

All the devices that convert some type of rotary motion to linear motion are "propellers". Side wheel and stern wheel propellers were some of the first types used, Rotary propellers (shortened to rotors) for helicopter's, and "screw propellers" for shafts that are inline with the direction of travel in airplanes and ships. The word "prop" is just convenient slang. It is like a dove is a pigeon, but a pigeon may not be a dove.

[@karlchilders5420]

uh, no, that is incorrect. You also have IMPELLERS as well. Think of wetbikes. Those rotac engines are even supercharged now making 200+ horsepower, and they use IMPELLERS. Drawing vs. pushing is the best way to think of the difference, without getting super technical into blade layout and design and all that. You don't need to comprehend the law of flow around an orifice and other advanced engineering concepts to grok this stuff. :D

[@maynardcarmer3148]

When my destroyer was in drydock, the props were being replaced. I saw the new ones lying on pallets on the dock floor, and yes, one was noticeably larger in diameter than the other, for that same reason.

[@kiereluurs1243]

Propellers.

[@RScottPR]

Does the paint cover any cavitation damage on the props?

[@norcalray7182]

I mean can you believe being on that big ship at 30 knots and then they would throw the helm hard over wow what a ride that must have been

[@PsRohrbaugh]

Props for uploading this video

[@8marcrara11]

Thank you for these videos. Good info from your expansion though some more time on the design drawings and layout would be appreciated . Enjoyed in Australia 🇦🇺