Hull Design software

I have designed a 4.9m cat on graph paper and I want to design it using CAD software. I understand it will take a while to design it on CAD but I am deternined to design the catamaran using CAD software. I am very confused on what software I should purchase because of the wide selection. I have experience with computers but have only used very basic design software before for other reasons. I do not want the easiest or the cheapest hull design software out there. I just want a hull design software that will let me produce a professional hull shape with no major problems, but I don't want to spend thousands on the most high tech software out there. Can anyone out there please advise me on the type software that I have described?
regards
Tom

[BillB]

Tom, I went through this software thing for a number of years, and finally realized the only good boat design software is a large piece of paper and a sharp pencil! The old way is the best way! Before investing (and I mean investing) in s/w that will only stylize your ideas, buy about 30 lbs of white molding clay and start sculpting a half-hull model. It’s fast and 3D. Take 5x8 white graph cards and cut the lines with a pencil. Blow up the card lines to full size and build your boat. No software for small craft does engineering. That is, tells you how thick the hull skins should be, what the flow characteristics will be (they are never correct anyway), what bolt sizes are needed, weight and balance, and any other technical details. Of course if you plan to build a 150’ yacht, then by all means buy the $150,000 software needed. Then you’ll need an IBM mainframe to get it to run right! Been there done that, and believe me, it isn’t worth searching for! Hire a marine engineer, for $300 per hour!
BillB

[sorenfdk]

Personally, I also prefer to do it the old-fashioned way, but I must admit that it is by no means better than using a computer - only slower! And there is the added benefit that the software can do the calculations for you (hydrostatics, stability etc.) much, much faster than if done by hand.
Software for small craft engineering is available, but probably not for craft of the size you mentioned.
I can't reaaly recommend any specific software, but try to get demos and try them out. This way you'll find the one that suits you and your needs.
The price of $150,000 that BillB mentioned is ridiculus, but you must be prepared to spend up to a couple of thousand, though (I should mention here that there are free- and shareware available, too - search for Hullform or PolyCad). All corrent software runs on ordinary PCs.
Good luck in your search!

Søren

[CGN]

Hi Tom, Bill is correct up to some degree, be sure of what you are looking for (or what you want to achive with the software results wise), this softwares are usefull but they are not magic boxes that you ask and they respond, so one quick response could be prosurf and rhino, it has worked for me, and they do most of what i need, this is for hull shape and interior detailing, other good one is hullform and rhino, hullform the pro version is quite complete, it may be little bit harder to use IMO, and again this is for hull fairing and lofting, stability (initial with rhino and prosurf) and complete with hullform, other people will be able to give you their opinions.

good luck, sounds like a fun project

Thanks for all the replies. The only reason why I'm considering purchasing CAD software is because all the most successful companies in the world, whether it is to do with yachts or to do with cars are using Cad software. I also understand that most of the modern catamarans are designed using CAD software. So if these companies that have turnovers of £500 million, then they must be doing something right!

[Andrew Mason]

I have to comment regarding Bill's statements about the high cost and complexity of modern CAD systems. Maxsurf costs as little as $700, yet was used to design the hull shape of Mirabella, the world's largest single masted yacht.

Similarly, Maxsurf was the system of choice of 7 out of 10 of the syndicates involved in the 2003 America's Cup. Each one of these syndicates could afford to choose whatever software they liked, and in many cases they were sponsored by major CAD vendors, yet they chose to pay full retail price for Maxsurf. CAD software does not need to be expensive to be effective.

I do not disagree that designing with pen and paper is a perfectly valid way of creating a hull shape, but it is slow, difficult to calculate volumetric properties, and inherently inaccurate, requiring the additional step of full sized lofting to create accurate lines to build from. As a result, few of todays professional designers still do things by hand, and more and more use computer systems such as Maxsurf, and are more than satisfied with the results.

Rather than imposing a fixed style on designs, I would argue that computer aided design methods have resulted in a greater degree of artistic freedom in the design of hulls and superstructures, particularly on luxury yachts that have gone from relatively simple shapes 20 years ago to a wide variety of more organic shapes, made possible by powerful surface modelling software.

The pic below, a design by Brett Bakewell-White of New Zealand, is a good example, initially modelled in Maxsurf with further detailing and rendering in Vellum 3D. Try doing this with a lump of clay!

[sorenfdk]

Those big companies probably did something more than just invest in CAD to create these large turnovers...

Please always remember GIGO - "Garbage in - garbage out" - and "To err is human - if you want to really f*** things up, use a computer!" The f-word is of course "foul" ;-)

[BillB]

Gee Guys, I was only trying to help !?!?!?
I must mention again, there is a BIG difference between Design software and Engineering software. Maxsurf and the like, are fine programs for small craft, and making beautiful displays, BUT they don't ENGINEER the boat! Try Fastship WITH all its add in tools, and see where the price goes. Any SHIP BUILDING software costs many thousands of dollars simply because in itself, it is huge. It takes years to master just parts of some of these professional programs.
Back to the reality of designing craft under 100 feet, which are considered small craft by all marine architects, sure one can figure out what size screws to use by eye, or state what thickness the bulkhead skins should be but I have never seen any Boat Styling software come close to doing this. If they did, you’d be paying many times the price because of liability.
As far as pencil and paper and clay models, this has worked for a hundred years, and is 100% accurate. Remember you the draftsman are creating the exact cut lines this way, the computer is always off by some.
“Everyone has his own opinion, unless it steps on the toes of others, then it’s a threat!”
Have a nice day, and build that boat!

[Andrew Mason]

Bill

On the contrary, Fastship has a relatively small number of integrated tools compared to Maxsurf. Proteus, the authors of Fastship, rely on GHS (by Creative Systems) for their hydrostatics and stability, NavCad (by Hydrocomp) for their resistance and propulsion, the US Navy SMP program for their seakeeping analysis, and ShipCam (by Albacore Research) for detailed structural design. Software that they have actually developed from scratch in-house consists of Fastship and Maestro, their excellent structural analysis package.

On the other hand, the Maxsurf suite consists of many well integrated applications using common files and a common user interface, all developed by my company, Formation Design Systems. These include -

Prefit - Surface fitting module
Maxsurf - hull surface modelling
Hydromax - Hydrostatics and stability analysis
Seakeeper - Strip theory based, frequency domain ship motions
Hullspeed - Hull resistance analysis, including Slender Ship Theory method
SPAN - sailing VPP
Workshop - parametric initial structural design
Multiframe marine - Structural analysis

Like Fastship, we rely on programs such as ShipCam for downstream structural design and production, as this is an area that we consider to be outside our area of expertise, however Fastship has no equivalent to our preliminary structural design program, Workshop.

I should also correct the impression you give that Maxsurf is for small craft and Fastship is for big ships. Maxsurf is used by shipyards of all sizes, including installations in 5 of the biggest shipyards in Japan - Mitsui, Mitsubishi, Kawasaki, IHI and Sumitomo. The enclosed photo is one of the most recent vessels constructed using Maxsurf and Workshop, one of the largest container ships afloat.

Finally, your assertion that pencil and paper and clay models are 100% accurate, while computers are "always off by some", is contrary to what most users experience. Admittedly, in Maxsurf you can set the tolerance to which curves are calculated, and the default is 0.2mm. If you think you can cut and build more accurately, you can always set the tolerance finer.

what is the best way to learn about the software for someone like me that has had no experience with CAD software?
regards Tom

[BillB]

Andrew, now that is the reply Tom is looking for, among the rest of us! Great reply!!
BillB

[Andrew Mason]

Tom, Bill

Please feel free to log on to our Academic web site ( http://msacademic.formsys.com) as a guest (i.e. User ID - guest, password - guest) and you can access our FAQ, manuals, and tutorials for all programs.

You can also download demo versions (i.e. no print, no save) of all our applications at our standard site http://www.formsys.com

regards

Andrew

Pretty impresive.... andrew, I am thinking about purchasing Macsurf. I much would it cost? I am not using the software to design a 80ft yacht, I would be using it to design a 4.9m catamaran.
TOM

[Timm]

Tom,

You may want to consider drawing and fairing your hull in a CAD program, not a hull design program. I still draw the basic shapes by hand and transfer them using points into Ashlar-Vellum Graphite ($995). I fair them the old fashioned way, just as I would on paper. When it looks good on screen, I plot it out on D size paper and take a long hard look at it, just as I would by hand. I calculate the areas of the hull sections using the 2D Analysis tool, then I input the areas, waterline halfbreadths and vertical centers of the areas into a spreadsheet to calculate the hydrostatics. This works fine for small boats and you have the CAD program to detail the rest of the boat, which is really the bulk of the design anyway.

I'll probably purchase a hull design package in the next year or so, but first I have to learn how to use the surface/solid modeling software (Ashlar-Vellum Argon) I just purchased. My mind can only handle so many complex programs at one time! Best of luck with your project.

[Andrew Mason]

Tom

Please contact me by email, AndyM at formsys dot com

Andrew