Groot Cross-Bow design

This is why independent objective data is required. What YOU personally feel is irrelevant. It must measure up against known accepted standards of compliance:

 

You have a real bee in your bonnet Ad Hoc. Are you trying to drum up business in your speciality or something ? You know SWATH doesnt cut it for 60% of load carrying craft at least ( cost of build, load carrying limitations etec etc) - and Josephs experience IS relevant.

If the boat can handle it, and the crew don't suffer, and the fuel use is affordable - its all good.

If someone finds a bit better way to do the big load carrying job - its good !!!!

 

Really??...how so. Unless you mean trying to separate subjective personal feelings from objective quantitative facts is a bee in my bonnet, then I plead guilty m'lud

To whom??

Can you see where I'm going with this??..yup "IF"...pure speculation and supposition. Or is that a buzzing noise I hear?

You can either debate about feelings, how you feel moved by the presence of an almighty being or how the stars talk to you at night...or...you can debate with facts and independent objective repeatable data.

Your choice....I know which I prefer

 

The third option is to question the standard. Is it applicable for the boat and function in question. Can data be obtained and a case made to challenge the applicability of the standard or call for further refinement.

 

Those numbers that Ad Hoc referenced and copied and example of have been established at those levels, or very similar, by nearly every classification and naval authority in existence worldwide...a result of more than 50 years of research in to motion-affected human factors and biodynamics.

Can the existing standards be questioned and improved upon further? My own testing experiences and observations suggest defintely so; the standards are too lax for all but the most acclimated IMO. But the motions standards we work to are the result of an incredible body of international research; my own reference library alone contains over 300 peer-reviewed technical reports on the subject and, therein, bibliographies naming well over a thousand more.

 

For HSC agreed.

The Classic O'Hanlon values are inadequate, too low, and they do not take into account lateral accelerations and the energy spectra are of higher frequencies compared to conventional vessels.

There is more and more evidence to readdress the standards for HSC vessels, at least, and no longer use the O'Hanlon MSI. Even as you note ISO 2631-1:1997 is much better, Not prefect, but at least more representative.

 

Reply form the designers

Dear Sirs,

I found your discussion when I was checking out replies on our latest designs on the internet. Happy to see we are triggering discussions and thoughts about designing ships for the future.

The 'Groot Cross-Bow' can be an (important) part of our total ship design package we offer to owners and builders. Before implementing the bow we analyze together with the client the proposed operational profile of the vessel, including dimensions and layout. This may result in the use of the Cross Bow-Bow and in combination with optimized hull lines and large size propeller we can accomplish significant reduction in the use of FO.

For Carisbrooke we designed a vessel with a main engine of 2400 kW on a 8700 dwt, single hold cargo vessel with iceclass FS 1A. If someone can find such vessel build before, please let me know.

Also without the use of the Cross Bow we can do so, at the moment the second vessel from a series of four, of sea-river vessels of 3700 dwt is being delivered to Wijnne Barends (part of Spliethoff group). This vessel is sailing >10 kn and is powered by a single Cat engine of less than 750 kW. The design is without Cross Bow, because of the airdraught and line of sight, but with optimized hull shape and large propeller.

For fast vessels (approx > 14 kn) we offer designs with a Groot Cross-Bow in combination with a bulbous bow, at the moment livestock carriers for Vroon are under construction at Cosco shipyard in China.

Besides the technical advantages the use of an other design from the ordinary, like a Groot Cross-Bow, may trigger the attention of investors and parties interested, so maybe you can consider it a marketing tool. But why not use it if it can give you an advantage on your competitors?

If you are interested in our designs, the possibilities and services we offer please visit our website (www.grootshipdesign.nl), or send me a direct message (janwillem@grootshipdesign.nl). Through our website and facebook page we will keep you and the maritime community informed about our designs and improvements.

Looking forward to further discussions and suggestions.

 

I think the current trend is toward building submarines.

 

Can you please define "significant".

Thanks.

 

If I take the design we did for Carisbrooke as example.
Recent vessels build before with (almost) identical design specs have approx between 3000 - 3500 kW Me installed, some even more. So the savings in the Carisbrooke design, compared to those previous designs will be, in my opinion, significant.

 

Whilst I applaud your positive attitude, the above is hardly quantitative independent verification.

You'll need to 'show and tell' much more to convince anyone beyond the rhetoric you provide.

 

Re-posting my stuff from another thread related to the issue of bow design:

By reading the discussions about plumb and reverse bows, sometimes one gets an impression that it is a kind of space technology, which comes together with carbon fiber composites and CFD analysis. The reality is - no contemporary designer or design firm has invented anything new there. These hull shapes, for example, have been crossing Mediterranean since the times of Ancient Greece and Roman Empire:











This one is a motorized version of an ancient Maltese Luzzu boat:


And so on...

Cheers

 

The most ridicules http://www.youtube.com/watch?v=hE4P-FG-Syg&feature=share

 

Original high tech ship.

 

We offer no magic but common sense in design. By pushing the limits in the design, trying to minimize the margins where possible, we already convinced some significant owners. The vessels that are under construction now and started sailing will convince more, I am sure we will see more vessels with Groot Cross-Bow's on vessels with optimized hulls and props.