Ship size vs. sea conditions

[2B@C]

Reading lots of posts and reviews about sailing from the west coast, particularly heading out to Hawaii, a common observation seems to be rough/choppy/bad seas the first day or two out, and the last day or two in, caused by crossing a particular current.

 

Later this year the Diamond will be taking Hawaii RT itinerary from the Island. Obviously the Diamond is a much bigger ship, and after some very informal research I found it is about 25,000 tons heavier and 17 feet wider (but suprisingly about 14 feet shorter). I would think those factors would help the Diamond handle the rough seas better, but I don't know about any differences in stablizer configuration, etc. Does anyone have any insight as to how a ship's weight, beam, draft, etc. affects how she rides? Has anyone who has sailed these two classes of ships noticed a difference?

 

I'm looking forward to reading the reviews once the Diamond starts making this run...

[NAS-KARR]

I can't be too concerned about the unknown (sea conditions) when planning a cruise. They'll be what they'll be, even a rogue wave will knock the hell out of your vessel. There's too many other things to consider when picking your cruise like...schools in or out, time of the year for climate purposes, size of the ship for pax count,itinerary choice not repeating previous ports of call and so on and so on. Sea conditions is non-existent in my mind.

 

Have a good cruise whatever e CIAO,

[Druke I]

Hull design and shape does influence how a ship will ride in rough water, as will the shape of the superstructure.

 

Gross generalization of course, but a longer ship with a narrower beam will usually ride better in pitching seas, as they tend to cut through the waves, as opposed to riding over and crashing down by the bow on the waves.

 

I don't think the Grand class and modified Grand class ride as well as the Coral class in pitching seas.

 

Don't place a lot of faith in stabilizers. They are designed to reduce roll, and are not effective for pitch. They will usually be retracted in pitching seas, as they tend to pull the ship down by the bow, much like diving planes on a submarine. That is not a good thing for a surface ship!

 

Ship's Engineers often advise the Captain to retract the stabilizers in normal sea state, as they cause a lot of drag, and reduce speed and fuel efficiency.

[FredS]

Just rode the Regal Princess from Cabo to LA and a couple of years ago road the Diamond from Cabo to LA. The Diamond was in Dec and the Regal just this month. On the Regal I slept with no problems and we had the most forward outside (A101) cabin on Aloha deck. The ship did not roll and the pitch was a very gentle movement. On the Diamond I thought there was more rolling and pitch. Going to LA you are running against the current and there is movement of the ship. The Regal, I understand, is the narrow knife like in hull design; like a ship designed for ocean cruising. Similar in shape to the Cunard ships. The newer ships are wider and do not have the deep keel so stabilizers are needed to keep the rolling motion down but they are still more noticeable rolling than the Regal. There was a notice posted on an information board on the Regal that said her stabilizers were mid-ships and would cut out 90% of the roll. Prior to Cable, all the way from San Juan the seas seemed calm so don't know if stabilizers were used or not, but our speed avg was 20 knots.

[Druke I]

Yes, the Regal is a good rider, with a good length/beam ratio. I didn't mention her in my previous post as she is leaving the fleet.

 

We've sailed her three times, most recent being Mar 06, 'round the Horn, Buenos Aires to Valparaiso.

[2B@C]

So it sounds like the shape of the hull has more impact on the ship's 'ride' than the weight of the ship. That seems to make sense. I have heard that ships designed for specific areas like the Caribbean have a flatter bottom and don't fare as well on the open ocean, I didn't know if Island was built that way or not.

[Murphey]

Good news to hear about the Regal, as we are leaving soon for Hawaii on her. Although we have been on her (and the (old) Crown) several times, we have never ridden on "open" seas on her....

[daveco58]

The problem between Cabo and LA, which you would also encounter coming back from HI, is it's "uphill". You are sailing against the Pacific Current, AND into the prevailing winds. The combination can make for a rough ride at times. Stabilizers help the side to side motion, but only length helps the up and down. The longer the ship, generally, the smoother the ride, as the boat has more swells beneath it at any given moment. But in a modern cruise ship, even a bad sea is pretty calm.

[joeinsb]

Hey gang, just to clear up a common misconception. The tonnage numbers associated with ships have nothing to do with weight. Gross Registered Tons (GRT) refers to the volume of all public spaces (cabins, lounges, dining room, etc, but not the engine room and such) with one ton being equal to 100 cubic feet. I don't know why the cruise industry uses the term, since it only causes confusion, but it's a means of indicating how much a ship can hold. You can Google GRT, but as I understand it, the term goes back to ye olde days when a tonne was a big container of wine that was hauled by a ship, which was rated by how many tonnes she could carry. Ask the Brits how tonne became ton.

 

You probably could figure out how much a ship actually weighs (I don't have a clue), but then I think you're talking about displacement or something. Anyway, I'm way over my head on that one, so have at it.

 

Michael, about stabilizers, on Century, which has a new active system that moves the fins to counteract to sea's forces, the stabilizers are out whenever the ship is at sea, or so our captain implied. They worked like a charm, by the way.

 

Hmm, the more I think of it, I don't buy the thing about stabilzers making a ship dive in a pitching sea. If you think of an airplane, which is compared to a ship in many ways, you don't change the angle of the elevators--which are what make the plane go up and down--just because the air is turbulent. Ya just keep flying her straight and level. Now maybe if the ship's stabilzers were fixed, I could see it. But with modern-day, adjustable, computer-controlled stabilzers, I don't think so. Nothing personal...:) Just my usual two cents worth.

[joeinsb]

I just Googled ship stablizers and got to this site--www.sperrymarine.northropgrumman.com--which explains the whole thing.

[Chivalrygirl]

Surely if you are going to go to sea you have to be prepared for what the weather and the sea throws at you? Otherwise why bother going to sea?

If its bad enough the stabilisers will be taken in and you will just have to put up with what ever happens. :eek:

[daveco58]

Hey gang, just to clear up a common misconception. The tonnage numbers associated with ships have nothing to do with weight. Gross Registered Tons (GRT) refers to the volume of all public spaces (cabins, lounges, dining room, etc, but not the engine room and such) with one ton being equal to 100 cubic feet. I don't know why the cruise industry uses the term, since it only causes confusion, but it's a means of indicating how much a ship can hold. You can Google GRT, but as I understand it, the term goes back to ye olde days when a tonne was a big container of wine that was hauled by a ship, which was rated by how many tonnes she could carry. Ask the Brits how tonne became ton.

 

You probably could figure out how much a ship actually weighs (I don't have a clue), but then I think you're talking about displacement or something. Anyway, I'm way over my head on that one, so have at it.

 

Michael, about stabilizers, on Century, which has a new active system that moves the fins to counteract to sea's forces, the stabilizers are out whenever the ship is at sea, or so our captain implied. They worked like a charm, by the way.

 

Hmm, the more I think of it, I don't buy the thing about stabilzers making a ship dive in a pitching sea. If you think of an airplane, which is compared to a ship in many ways, you don't change the angle of the elevators--which are what make the plane go up and down--just because the air is turbulent. Ya just keep flying her straight and level. Now maybe if the ship's stabilzers were fixed, I could see it. But with modern-day, adjustable, computer-controlled stabilzers, I don't think so. Nothing personal...:) Just my usual two cents worth.

 

You are right on about Gross Register Tons. A Ship Registry, like, Lloyds will also generally list a ships "displacement" as well as it's "dry weight" (meaning unloaded). Container ships are still rated by how many 40 foot containers they will hold. Ship "size" is a very confusing thing, because different measurements, of different ship types, are needed for different reasons.

[Druke I]

To add further confusion to the ship size question, now some lines are starting to use GT (gross tonnage) rather than GRT (gross registered tonnage), which eliminates the square footage of all the balconies from the latter figure, reducing tolls through the Panama Canal, the rationale being that balconies' footage should have never been included in the 1st place!

 

(And that is a long sentence!)