Prima bow shape

[BrianF]

I noticed that the bow on the new Prima is not swept back like most cruise ships. Instead the bow drops straight down or even a little forward.

Why is this, is it more efficient or is there some other reason?   I do not like the shape and think it is very ugly. 

[HuliHuli]

From BoatTest.com: "Bows need to have some or all of the following qualities: offer low resistance to motion through the water and thus best fuel economy in both calm and rough seas, minimize pitching motions and pitch slamming, minimize spray and wetting, offer lots of room inside the hull for accommodation, not let green water over the foredeck — the list goes on. So, the bow of a boat has a number of jobs to do — often a jumble of conflicting requirements that — as with so many elements of boat design – call for prioritization and compromise. A good solution for one problem can quite readily create new problems or less desirable knock on effects. Understanding the requirements of the proposed new boat and the owner’s expectations and priorities is thus a very important first step in the design process."  NCL's Prima as well as Virgin Voyage's Lady ships have clearly chosen a new path based upon all of these design factors.

[CruiseCaptain]

On 10/13/2022 at 12:02 AM, BrianF said:

I noticed that the bow on the new Prima is not swept back like most cruise ships. Instead the bow drops straight down or even a little forward.

Why is this, is it more efficient or is there some other reason?   I do not like the shape and think it is very ugly. 

@BrianF and @HuliHuli, I think it has something to do with the ship being LNG-powered. I've noticed all the LNG-powered cruise ships have these type bows. Maybe someone else who knows the technics of this could share some insights.

[Kendall James-Vargas]

@HuliHuli Thanks for sharing that information! 

@BrianF I guess it may be more of a practical design feature! 

@CruiseCaptainI think that's a great point. I didn't even think of the relationship of the bow shape and LNG ships. 

[kefthecruiser]

Let's look at this a little closer -

NCL Prima and Virgin Lady ships (vertical bow) use fuel oil. Carnival Mardi Gras and Celebration (sloped bow) use LNG. Older ships, burning fuel oil, have sloped bows. There is not a relationship between bow shape and fuel source. Changing bow shape is likely a design change that improves a characteristic that the ship owner wants. I would guess it is more efficient, lowering fuel consumption, etc...

[Kendall James-Vargas]

@kefthecruiser Thanks for adding to this post! Possibly this bow shape could be more dynamic and fuel efficient. It could be similar to car designs. Some cars are more aerodynamic than others, but the design could also just be a matter of appearance. It is possible, however, that LNG ships are looking for the most fuel efficient bow shape in some cases. 

@BrianF and @HuliHuli and @CruiseCaptain Do you agree?

[kefthecruiser]

I would just add that all ship owner / operators are looking for ways to be more fuel efficient, cost effectively. Also interesting to note that the vertical bow design is rather "back to the future". Think of ships like the Titanic and others of that vintage - all had vertical bows. The industry is also adding air lubrication systems to the hull. Google that - it's rather mind blowing to this engineer. Perhaps a topic for another thread.

All in all though, as a passenger, I'm much more interested in the journey and on board amenities than the ship design.

[Kendall James-Vargas]

@kefthecruiser That is so very cool! Introducing a new thread about this is a great idea. I would love to learn more. I will create a post on this topic.