Axe Bow

Tz3dcom, just to add, the bow you show in post #1 is a chined modification of the Ulstein Group Asa X-Bow (TM). It is not an axe bow ( File:Verschil tussen een conventionele (441) en een bijlboeg (442).JPG - Wikipedia https://en.wikipedia.org/wiki/File:Verschil_tussen_een_conventionele_(441)_en_een_bijlboeg_(442).JPG ) or a ram bow ( File:USS Zumwalt (DDG-1000) at night.jpg - Wikipedia https://en.wikipedia.org/wiki/File:USS_Zumwalt_(DDG-1000)_at_night.jpg ). In both the ram or axe bow, the configuration of the waterlines above the DWL is linear whether the stem is vertical or sloped aft. Your bow appears to show distinct tumblehome which is the key feature of an X-Bow (TM).

 

Our French coast guards have their new 32m boats with that kind of bow, seems satisfy with, I can see the one sailing in Nice, the sea state when any is very short (typical period 3-4 secondes), with no swell superposed :
LEVANTE DF 33 - Bateaux-Fécamp https://www.bateaux-fecamp.fr/levante-df/

 

... And our new rescue boats designed for heavy duties have adopted the jigsaw bow, here this video unfortunately by flat sea :

 

It is ORC Pantocarene /Didier Marchand who develops that kind of bow, also adopted for pilot boats, here an Australian built one on sea state :

 

Those are all still atlantic bows, the designers are just playing games with the cutwater to get more LWL in minimal (SS 2-3) sea states. In the significant event, those bows function just like a typical flared atlantic bow, which is much different than the shape proposed by Tz3dcom.

 

Hi Jehardiman,

Thanks for your more comments. But I don't think my bow is a X-bow ,because X-bow without the bulbous bow and chin line.
You can see below section of my bow ,It's different to the X-bow.and I think it's a new hybrid bow design. It may work wellin most seaway . About the wave slap to the forward window.I also do not think it's a problem ,because today a lot of low profile sail boat with forward window and without the Atlantic bow. as well as the function of this yacht is recreation , not the racing as sailboats.

 

I agree, my examples are not in tune with the proposed concept.
As regard this concept for relatively small boat : only one nose down a little harder in the trough of a wave can be sufficient to bring disaster, i.e. greenwater impact on the very exposed wheelhouse windows. The question is whether the behavior of the ship facing rough sea is healthy and predictable enough in relation to this risk, can the captain regulate his speed facing the sea with a safety margin, whithout the one brings an Atlantic flare bow ?

 

Several large (significantly over 100 feet) yachts were anchored in Penobscot Bay, Maine yesterday.

 

I would suggest to get some boating experience prior to start designing boats. This will help understanding those questions about bow.
Unfortunately, these days many people with very limited boating experience jump into yacht design... and straight to superyacht design.

 

You know, if Congress did the same (publish the title of the bill, then hold town hall meetings to glean ideas for what fits the title, and then quickly vote on that) it might actually be an improvement over the way they now let staffers endlessly spew out unreadable and vague text. Keeping in mind that "improvement" still wouldn't be "good".

 

I think you guys are being a little harsh. He did say concept, not design. How many automobile concepts ever get built (if they even drive in the first place)?

 

I know for an absolute fact no person writing on this forum can be as harsh as the sea and physics. Neither the sea nor physics cares about your concept or your design, so it is therefore imperative you conform them with engineering due diligence and quantized risk management.

Chapelle, in the very first paragraph of the very first chapter of his seminal work "The History of American Sailing Ships" lays out the responsibilities of the naval architect.

 

I'm with ziper1221 on that one, and would even go further: Isn't that old definition of a naval arch as the all-encompassing designer-engineer-headOfSecurity-stylist-brandmanager-yardDirector getting a bit dusty ? I mean i admire the wealth of multidisciplinary experience that many have accumulated towards the ends of their careers and i wish everyone who sticks to the field with such passion for such a long time the same. But few will even have the opportunity, it was always hard in the field, even before any kind of linear career became incredibly rare in whatever profession. And there are also good reasons for more and more people to work in increasingly horizontal teams, as do most other technical industries these days: checks & balances instead of a single point of failure, combined depth of specific expertise, motivation & stimulation on a more daily basis, enhanced constant learning through emulation making it easier to find your way into the next speciality, concurrent engineering for much better flexibility and time-to market... Some will regret the dillution of responsibilities but i'd happily oppose that maximising the chances to catch errors before a boat goes down, just as we do here, is more productive than knowing whom to jail in case of a catastrophic outcome. In such a setting, tz3dcom has been working on looks and a preliminary GA as part of the cristallization of the SOR and marketing approach, and now he's starting to check the feasabilities. And i bet if he generates some interest with these ideas, he'll also be able to network with people doing the actual engineering, at least as well as many folks stuck in their top-down shemes. Also sometimes i wonder why naval architects have this tendency to treat a nice preliminary 3D drawing as a design when it's just the up-to-date equivalent to their napkin sketches. Software has come a long way in terms of ergonomy, speedy visualisation and integrated cross-checks. The generation now trying to enter the field are simply native to it and express themselves that way because it is convenient, efficient and ready for follow-up with a full team.

 

In our office, the Concept Design is:
- Parametric study of craft
- 3D model of exterior
- Renderings of exterior
- Optional: renderings of interior - just few views, to show level of finishing
- Lines plan
- Preliminary general arrangement drawings
- Preliminary lamination schedule (for composite craft) or preliminary list of materials for metal craft
- Preliminary table of weights
- Preliminary stability calculations and assessment
- Performance and seakeeping predictions
- Preliminary calculations of structure
- Preliminary specifications of equipment - deck, systems, electrical, propulsion

The Concept Design answers 3 questions: a) How the boat looks? b) Is the boat feasible and safe? c) Provides data for preliminary cost estimates.
If rendered images of the boat are not supported by such basic set of naval architecture analysis, they have very little value.

So don't confuse Concept Design with 'pictures'. There are a lot of 'pictures' in the Internet, will never become a reality.

 

So you're suggesting your 'concept' is just a pretty picture then anyway - since it is not even going to get its bottom wet!
It is merely for show...

Indeed!!
As I often cite, try taking you "idea" into the middle of the North Sea on a cold dark stormy winter's night.. do you still feel safe with your idea?

Who made you the arbiter on the definition of a naval architect to suggest it is - getting a bit dusty??
A naval architect is just that.. a multidisciplinary person which is summarised with the old phrase of... jack of all trades, master of none.

Just because you do not ascribe to this definition or do not wish to, do not presume to speak for others on this subject that do conform to this definition. It is a long slow road one in which today's NAs appear too impatient.
10 eyars of experience, - still takes ten years! ... many seem to wish to convert 10 years of experience into a 10 seconds on a Google search as an equivalence.... It isn't the same, not by a loooooong shot!

NA who are structural engineers or hydrodynamicists etc etc, that's great. But they are single discipline not multidisciplinary in their roles. Do not confuse the 2, as they are poles apart. If you have or know of others who have taken this single disciplinary route/career, do they feel they are missing out or not fully trained?? I doubt it..as many of my friends have fall into this category and simply do not wish to be a multidisciplinary NA, but they do not dismiss it as - getting a bit dusty. It is just not for them...

Because the person creating the 3D drawing covets praise - as if it is a "design" and a finished working design at that - which it is not. Sketches on a the back of a fag packet or napkin, can be treated and criticised as such whether a sketch on the napkin or a fancy 3D image with sound technical reasoning and understood by the NA. But a 'stylist' only hears subjectivity, not objectivity - and that's the difference! Because their 3D sketch is either... just a fancy looking shape, in which case, one can only ascribe subjective opinions on the shape....or... it is a working Design, in which case all technical criticisms are all valid and must be taken as such, objectively and answered rationally with equal technical aplomb.
A shape, not matter how it is generated and coloured is only a subjective point of view... until it is not, and then it is more than just a shape - it has function!

Exactly...

Anyone can draw a shape and add colours via computer graphics - but it still doesn't make it a functioning Design!