chengkp75

Quite a lot of cruise ships carry two different fuels these days, one for use in ECA's and one for outside. They feel it is cheaper and less likely to cause problems like this to go this way over scrubbers. For years, ships had to switch to low sulfur diesel when docked in EU ports, even if the ship had scrubbers, so carrying two fuels is common.

The ship's carpenters or the fitters in the engine room should be able to come up with a cut off mop handle, or 1" PVC pipe section. Ask guest services, and maybe a tenner to the guy who delivers it (he made it).

If that is the case, then in fact the engine could be run without the scrubber working, they would just have to use a more expensive fuel.

And the cruise ships have nothing in common with the FDA. It would require paxlovid to be approved in the flag state, not the US.

If you look at the size of a trim tab in comparison to the size of the boat, both length and weight, and then extrapolate that for a cruise ship, you get an enormous appendage sticking out the back of the ship (about 40 feet or more). That would lead to larger port fees (longer berth). Putting motors in the tails to operate them requires access to service and maintain them, and they would need to be very large, or you have ugly hydraulic cylinders attached between the aft dining room windows. And, the force to dampen rolling is limited, as the center of the tabs is close to the center of the ship, so little moment arm. You would also have to have these flapping up and down to counteract rolling. If you mean to minimize listing or heeling instead of rolling, again, the force from anything less than an enormous tab would do nothing. Not following you about air flow.

Archimedes never said that a submerged object, either fully or partially, "pushes up". Any object, when either partially submerged (ship) or fully submerged, pushes down with the force of gravity. It is the water that is displaced by submerging the object, that is trying to re-occupy the space of the object, that pushes up. But let's let that go. The duck tail almost never goes more than a few inches into the water. The closest analogy I can think of is a trim tab on a speed boat. Do you know what I mean? The little flaps on the back of a boat that can be hinged up and down by hydraulic cylinders to force the bow back into the water. Their area is miniscule compared to the waterplane of the boat, yet their effect is great in adjusting the trim of the boat and forcing the bow back into the water. They are just flat metal, no air space in them, yet they act to depress the water (forcing down) behind the boat, and the "equal and opposite reaction" is to force the stern up, lowering the bow. The duck tail is similar, merely extending the flat area behind the propellers to increase the down force on the water. The only reason the duck tail is not just a flat piece of metal like a trim tab is structural, at it's size, it needs to be reinforced, so a box girder shape is stronger than a flat sheet (think of a cardboard box holds up more weight than a sheet of cardboard).

Not really. The "hull form" is what is under the waterline. Stability does not depend on the shape of the ship above the waterline. The "duck tail" is nearly 100% above the waterline, and doesn't affect the volume displaced (changing the center of buoyancy). Changing the center of buoyancy moves the "metacenter", which is the point that the center of buoyancy rotates around when the ship rolls or pitches. "GM" is the distance from this "metacenter" to the center of gravity. While a duck tail does is provide a small amount of additional waterplane area when the stern goes down in pitching, the amount of change to the waterplane area is very small compared to the upright waterplane area (900 foot long hull, 10 foot duck tail). What the duck tail really does is provide an additional air volume that the ship is trying to submerge when the stern pitches down, and that air volume creates more buoyancy. But, the duck tail never really goes underwater to change the amount of buoyancy, it just makes it harder for the rest of the stern of the ship from going down deeper.

Stability is "Ship stability is the ability of a ship to float in an upright position and, if inclined under action of an external force, to return to this position after the external force has ceased acting." Therefore stability does not care how much a ship pitches or rolls, it cares about the ability of the ship to return to upright from that pitching and rolling. A duck tail or a flared bow are more akin to roll stabilizer fins or tanks, that seek to dampen the pitching, but do not affect the ability of the ship to generate righting moment. This is a common misconception with non-mariners, thinking that a "stable" ship does not roll, when in fact the more stable a ship is, the more uncomfortable the rolling is (snap rolling). The most comfortable ship to be on in a seaway is a loaded single hull tanker, that has virtually no "GM", the measure of a ship's stability, as this ship will roll very slowly, and likely "hang" at the end of the roll (to one side or the other) before "deciding" (by eventually building righting moment) to return to upright. These rolls can be measured in minutes from one side to another, unlike a cruise ship that typically rolls in less than a minute.

A "duck tail" or stern sponson is never "needed" for stability. It is added to provide reserve buoyancy to reduce pitching, just as the "flare" of the bow section above the waterline does the same thing, but doesn't do anything for stability.

Jade was the Pride of Hawaii when built, and the Sky went to Pride of Aloha, and then back to Sky. That was part of the deal with Congress when NCL America took over the partially built hull of Pride of America. They could flag in an existing foreign built ship, and also flag in a foreign built newbuild, and have all of them be PVSA compliant.

Since the engineers in the ECR have a monitor for the surveillance cameras, I had to keep on top of whether they were paying attention to the plant, or watching the "free shows" or zooming in on passengers walking off the gangway.

No, it means that state tax (about 4-5%) is added to any purchase made on the ship while in port. Whether you have a beverage package or not, or purchase something in the store, or a specialty coffee or whatever. Once the ship leaves the 3 mile limit, the POS registers are reset to not charge state sales tax.

And the crew will focus the bridge wing cameras on your balcony and get some adult entertainment.

And look how much profit the Navy makes. Most of that on the Navy, and on commercial ships as well, is known to be a waste of money, and is done just to keep the crew busy. Many ship owners (fair enough, not cruise ship lines, as they care more for cosmetics) don't even stock paint on the ship, as they know it is just money thrown away, and they get far better for their money when the paint is completely gone over in shipyard every 2.5 years.

So, you think it would be money well spent to grind off the gel coat on the lifeboats and apply a new gel coat just to change the color? That's not paint. Huh? If they are doing a drydock now, that is not a statutory docking, and does not give them "credit" towards the docking due in 2024, which is the 15 year survey. There is only a six month window where a docking can be done ahead of time and get credit for it.

His point was to refute your statements in earlier posts that: 1. "There is only one cruise ship in the world that is US registry", and then 2. "that vessels that operate only domestically must be of domestic registry since they are unable to safely make stops outside the US. While the particular vessel in the photo does not make foreign port calls, it can do so safely, and that is not the reason the vessel is US flagged. As I've noted above, both UnCruise and Lindblad operate US flag small cruise vessels that routinely make foreign port calls. Your statement implied that the only reason a ship would flag US was because it couldn't go to foreign ports safely. The reason these vessels are flagged US is to allow them the choice to offer cruises that only go to US ports. The Pride of America is US flag, and operates "only domestically". Do you feel she is not "safe" to travel to foreign ports? What about the Norwegian Jade and Sky? Both of these were at one time US flagged.

Not sure what you mean by "balanced" for pool chemistry. Since cruise ship pools are drained and renewed so frequently, they do not need lots of the chemicals that land based public pools use to maintain the viability of the chlorine. Ship's pools use chlorine and acid, period. And, as the water is drawn through the filtration system (continually), that water is checked continuously for pH and chlorine residual, and a dosing pump is controlled based on the sensor readings. Salt water averages around a pH of 8.2, and chlorine works best as a sanitizing agent at 7.2 to 7.8, so some acid is always needed. The chlorine residual is kept at a constant 3-4ppm (allowed 1 - 5), which is higher than most home pools, and this high chlorine is what leads to most complaints about the pools, either fading of swimwear, or rotting out the stitching of the swimwear. SPA pools are required to be kept between 3 and 10 ppm of residual chlorine, the same as the hot tubs.

As these use a 3M adhesive strip to adhere the lock to the door, there will likely be damage or residue on the door, and possible charges for this.

Could you please provide a link for this lock, as I can help with whether it would be allowed or not, or whether it would work, having maintained cruise ship door locks in the past.

This is also an incorrect statement. The majority of the US flag cruise vessels mentioned above can safely make stops outside the US, using the National Geographic Lindblad ships as example, they routinely, and were designed for, cruises to Central America from the US west coast. These ships and lines choose to be US flagged, so that they can offer strictly domestic cruises. Many of both UnCruise and Alaska Dream vessels that are currently doing Alaska cruises were built on the US East Coast (wonder how they got to Alaska if they couldn't safely make stops outside the US?). And, if you look, you will see that there is a large section of CC dedicated to river cruising, and the smaller lines mentioned as coastal cruises are represented under "other cruise lines" forums. And this particular forum is a general cruising question one, so not just about "ocean liners" (which the Cunard purists will tell you that Princess ships are not).

A lot of it probably was, but this is not something that just happens once. It is a continual process, where rust is dealt with in one area, and the next day some pops up in another area. Same with varnish failure. Even when the ships were running full time before covid, the crew were dealing with this daily. And a minimum crew. None of this would require a visit to the shipyard, though "fabric maintenance" (the preferred term for chipping and painting) is done better when addressed by shipyard practices over what can be done by crew. Most of that painting you see of the hull, and even most of what is done during cruises with the crew chipping and grinding away rust and repainting, is mostly cosmetic. Unless you sandblast the steel down to gray metal and recoat, the rust will come back sooner or later.

"Rustoleum" is virtually worthless in a marine environment. No rust short of extremely light "flash" rust (where bare steel has rusted in the day or two before it is coated) can be successfully covered with a "converter" (far better than Rustoleum), and not on edges.

Alaska Dream Cruises, and Lindblad National Geographic also operate US flagged small cruise ships.

It could also be a cabotage thing, because Costa is Italian flagged (EU) as are some of MSC's ships (Malta). I see that the next port is in Greece, so there wouldn't be any cabotage issues for the OP, but there could be if the remaining ports were in Italy, as the OP would be essentially taking a cruise from Florence to end in Italy without visiting another country, and that would not be allowed on a ship that is not flagged to an EU member nation.

This is not quite correct. While they typically don't open a bag during embarkation, the ticket contract gives them the right to search your cabin and baggage without your presence or knowledge.