Ex techie Posted October 20, 2016 Author #176 Share Posted October 20, 2016 The rudder bulb closes the gap between the rudder and the prop. Usually they are about the same size as the hub of the rudder. It helps to streem line the water flow. Arthur, Here's a shot of the Wonders rudder bulb: Actually, virtually every cruise ship I've seen with rudders has a "trim tab" or Becker rudder. Rudders tend to lose effectiveness with ship speeds below 3 knots, which is why thrusters were introduced. Thrusters on the other hand, tend to lose effectiveness when ship speeds are above 3 knots. Becker rudders were introduced to bridge that zone and provide redundancy. These rudders will act like airplane ailerons and provide sideways "lift", even at slow forward ahead or astern speeds, because the water flow from the propeller is enough to create the lift. Our Captains and Staff Captains would practice making dockings and undockings with various systems "out of order" (still running but not used), like not having stern thrusters and using the propellers ("splitting" them, or putting one ahead and the other astern) and rudders only. When trained, performance was nearly identical. Chief, Guess this is what you meant by a Becker rudder? I did a little homework on them and found this old article about the Dream where they installed "twisted spade flap rudders", are they the same but by a different name? Also with the Dream they decided on fixed/bolted propellers so the blades could be changed underwater if damaged, but also the pitch changed as the ship get's older. http://www.cruiseindustrynews.com/cruise-news/5016-disney-dream-technical-behind-the-scenes-sp-1720472616.html They also painted the hull with a new type of coating with a lifespan of 20 years after testing it on the Magic. I wonder if they have done the same with the Wonder after her hull was stripped back to bare metal? ex techie Link to comment Share on other sites More sharing options...
Tkerniroc1986 Posted October 20, 2016 #177 Share Posted October 20, 2016 ex techie Woooo!!!! She's in the water again! Sent from my iPhone using Forums mobile app Link to comment Share on other sites More sharing options...
Ex techie Posted October 20, 2016 Author #178 Share Posted October 20, 2016 The one on the Wonder' date=' IMHO is weird. It is better than the piece of junk they put on the Magic, but still--an odd choice. However, the Imagineers didn't confer with me before they allowed their quirkiness to run wild.[/quote'] I think it will be interesting when we see a shot from directly below the chandelier. I Wonder if it will look like a crimson death star?! :D :eek: ex techie Link to comment Share on other sites More sharing options...
chengkp75 Posted October 20, 2016 #179 Share Posted October 20, 2016 That is in fact a Becker rudder, the "flap" part of "twisted spade flap rudder". However, the "twisted spade rudder" refers to the leading edge, rather than the trailing edge, which has the flap. These rudders have their leading edge offset to port or starboard to match the water flow from the propeller. The propellers turn in opposite directions, so the water leaves the propeller more on one side than the other, so offsetting the leading edge into this flow increases efficiency. I think the idea of changing the pitch by changing blades is a bit of wishful thinking, as the cost would be great and the incremental speed would be small. Sounds nice, though. These new "hard" coatings for ship's bottoms are the hot thing now, for ships that do over 15 knots. Most cargo ships have slowed down, and they don't deal with these paints. They are very expensive. They are basically a hard teflon surface, the idea being that the surface is so hard and smooth that marine growth cannot find a point of attachment that will survive the water flow at high ship speeds. RCI is doing this on most of their ships now, it is the bright blue bottom paint. Link to comment Share on other sites More sharing options...
moki'smommy Posted October 20, 2016 #180 Share Posted October 20, 2016 I think it will be interesting when we see a shot from directly below the chandelier. I Wonder if it will look like a crimson death star?! :D :eek: ex techie Like button! Link to comment Share on other sites More sharing options...
Ex techie Posted October 20, 2016 Author #181 Share Posted October 20, 2016 That is in fact a Becker rudder, the "flap" part of "twisted spade flap rudder". However, the "twisted spade rudder" refers to the leading edge, rather than the trailing edge, which has the flap. These rudders have their leading edge offset to port or starboard to match the water flow from the propeller. The propellers turn in opposite directions, so the water leaves the propeller more on one side than the other, so offsetting the leading edge into this flow increases efficiency. I think the idea of changing the pitch by changing blades is a bit of wishful thinking, as the cost would be great and the incremental speed would be small. Sounds nice, though. These new "hard" coatings for ship's bottoms are the hot thing now, for ships that do over 15 knots. Most cargo ships have slowed down, and they don't deal with these paints. They are very expensive. They are basically a hard teflon surface, the idea being that the surface is so hard and smooth that marine growth cannot find a point of attachment that will survive the water flow at high ship speeds. RCI is doing this on most of their ships now, it is the bright blue bottom paint. Thanks Chief! ex techie Link to comment Share on other sites More sharing options...
Ex techie Posted October 20, 2016 Author #182 Share Posted October 20, 2016 ex techie Link to comment Share on other sites More sharing options...
Ex techie Posted October 20, 2016 Author #183 Share Posted October 20, 2016 ex techie Link to comment Share on other sites More sharing options...
Ex techie Posted October 20, 2016 Author #184 Share Posted October 20, 2016 For those interested in the engineering side of the ducktail, there is a heap photo's in the Facebook Album: https://www.facebook.com/pg/Mart%C3%ADn-Bah%C3%ADa-265783340447722/photos/?tab=album&album_id=316848298674559 ex techie Link to comment Share on other sites More sharing options...
Ex techie Posted October 21, 2016 Author #185 Share Posted October 21, 2016 ex techie Link to comment Share on other sites More sharing options...
Ex techie Posted October 21, 2016 Author #186 Share Posted October 21, 2016 ex techie Link to comment Share on other sites More sharing options...
moki'smommy Posted October 21, 2016 #187 Share Posted October 21, 2016 Donald certainly looks unhappy at being tangled in those ropes! Great pics. Link to comment Share on other sites More sharing options...
Tkerniroc1986 Posted October 21, 2016 #188 Share Posted October 21, 2016 (edited) Donald certainly looks unhappy at being tangled in those ropes! Great pics. And he looks even more unhappy when the nephews are trying to cut the ropes lol Sent from my iPhone using Forums mobile app Edited October 21, 2016 by Tkerniroc1986 Link to comment Share on other sites More sharing options...
Ex techie Posted October 21, 2016 Author #189 Share Posted October 21, 2016 Donald certainly looks unhappy at being tangled in those ropes! Great pics. And he looks even more unhappy when the nephews are trying to cut the ropes lol LOL! It's good to see the right side of his face and expression you usually cannot see! ex techie Link to comment Share on other sites More sharing options...
Ex techie Posted October 21, 2016 Author #190 Share Posted October 21, 2016 ex techie Link to comment Share on other sites More sharing options...
Ex techie Posted October 21, 2016 Author #191 Share Posted October 21, 2016 It appears the crew were issued with Magic Bands and smartphones to track them onto the ferry's that served as crew accommodation during the refit. Maybe this is a step closer to Magic Bands being used by Guests? ex techie Link to comment Share on other sites More sharing options...
EJanss Posted October 21, 2016 #192 Share Posted October 21, 2016 ex techie Would it be too obvious of me to say it's "Almost the..."--Yeah, guess it would. :o Link to comment Share on other sites More sharing options...
Tkerniroc1986 Posted October 21, 2016 #193 Share Posted October 21, 2016 It's so exciting to see her nearing completion! I wish I could be on that first cruise to see all these new improvements! Sent from my iPhone using Forums mobile app Link to comment Share on other sites More sharing options...
EJanss Posted October 21, 2016 #194 Share Posted October 21, 2016 (edited) It appears the crew were issued with Magic Bands and smartphones to track them onto the ferry's that served as crew accommodation during the refit. Maybe this is a step closer to Magic Bands being used by Guests? It's useful for security and check-in, but Bands would take away from the Key card being inserted as your room "power switch" on most ships, where conserving electricity is more of an issue at sea. Unless they're planning to issue new cards just for that. Edited October 21, 2016 by EJanss Link to comment Share on other sites More sharing options...
Ex techie Posted October 21, 2016 Author #195 Share Posted October 21, 2016 It's useful for security and check-in, but Bands would take away from the Key card being inserted as your room "power switch" on most ships, where conserving electricity is more of an issue at sea. Unless they're planning to issue new cards just for that. Yes there is that, however many people have figured out that any old card (library, used gift card, pre cruise hotel room key) will work in the switch and use that instead of their KTTW. TBH, the switch only controls the lights, and while good was initially installed when incandescent light bulbs were in use. The ships have now switched to either compact fluorescent or LED lamps and the consumption even when left on is minimal in comparison. It has led to a greater awareness and more people are conscientious of switching off the lights when leaving their Stateroom. ex techie Link to comment Share on other sites More sharing options...
EJanss Posted October 21, 2016 #196 Share Posted October 21, 2016 (edited) TBH, the switch only controls the lights, and while good was initially installed when incandescent light bulbs were in use. The ships have now switched to either compact fluorescent or LED lamps and the consumption even when left on is minimal in comparison. It has led to a greater awareness and more people are conscientious of switching off the lights when leaving their Stateroom. Aww. I remember visiting California hotels during the Enron crunch, and many hotels had started using power cards for conservation-- Although you couldn't immediately come back to an air-conditioned room, it just felt good to know the lights and devices were off. Not to mention, as DCL travel agents point out, having a "holder" by the door to always know where your KTTW is. Also has to deal with the issues of Bands on the beach, and those that might get lost on the way back from Castaway--Nice to have bands for shopping/food, but more likely to be taken off/left for swimming. Edited October 21, 2016 by EJanss Link to comment Share on other sites More sharing options...
Ex techie Posted October 21, 2016 Author #197 Share Posted October 21, 2016 I have to say I am a little disappointed in the standard of painting. This picture shows a lot of overspray, and "touch up" paint on the hull. Yes this will be below the water line, but in clear blue Caribbean water you can see below the water line. I'm surprised DCL were satisfied with this. ex techie Link to comment Share on other sites More sharing options...
Tkerniroc1986 Posted October 21, 2016 #198 Share Posted October 21, 2016 I have to say I am a little disappointed in the standard of painting. This picture shows a lot of overspray, and "touch up" paint on the hull. Yes this will be below the water line, but in clear blue Caribbean water you can see below the water line. I'm surprised DCL were satisfied with this. ex techie I'm sure the ballast tanks will put that well below the waterline. Or eventually it will be touched up, who knows, but by the looks of it, the line there will be close to, or that line will be below the waterline. Sent from my iPhone using Forums mobile app Link to comment Share on other sites More sharing options...
chengkp75 Posted October 21, 2016 #199 Share Posted October 21, 2016 I have to say I am a little disappointed in the standard of painting. This picture shows a lot of overspray, and "touch up" paint on the hull. Yes this will be below the water line, but in clear blue Caribbean water you can see below the water line. I'm surprised DCL were satisfied with this. ex techie This does not look like the hi-tech hard bottom paint. This looks like "self-polishing copolymer" anti-fouling paint. Those touch up spots will fade very quickly and the entire bottom will change color quickly, going from gray to a reddish gray. Lots of those areas appear to be hull openings where they had either wood plugs and extensions, or welded extensions to keep water runoff (like from open deck scuppers) away from the hull during painting. Some you can see, they pulled the plugs soon after the paint was dry, and there was either rain or deck cleaning, which resulted in the rust stains, but these should be below the waterline, and the rust stains should disappear. There is a bit of overspray below the white boot top, but I think this paint won't survive much submersion in sea water. Link to comment Share on other sites More sharing options...
Ex techie Posted October 21, 2016 Author #200 Share Posted October 21, 2016 I'm sure the ballast tanks will put that well below the waterline. Or eventually it will be touched up, who knows, but by the looks of it, the line there will be close to, or that line will be below the waterline. I know. I guess I'm just too fussy about things like that! This is her regular waterline pre drydock: ex techie Link to comment Share on other sites More sharing options...
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