Are computers worth it?

[Phil Thompson]

Hello

I may be letting myself in for a beating but I want to know what the downsides of going computer are when designing a boat. I have designed a small trailer sailer cat prototype which sails well. The boat has three bunks real accommodation and a large cockpit. I want to make some small changes before I try and design another one.

The crux of the problem. Is it worth my while to buy and learn computer design or should I just get back on my piece of chipboard and loft it up. Lofting the prototype gave me full size sections and took about one and a half days. She came out prety well although I underestimated the weight of the boat. (My fault - I was doing it cheap not light) Amazed she sails well at all.

I have built three multihulls - 2 x 38 footers and the little 6 metre trailer sailer cat. None have been computer designed. The little cat was my design (the others weren't) and didn't take me that long after initial calcs on graph paper.

What are the main advantages of going computer over lofting? - I can loft already and pencils and chipboards are cheap. Will I design the new boat any faster after learning software or any better?

cheers

Phil

[Tactic]

The main adavntage of computers as I see it is to be able to look at all the different possibilities faster than by manual lofting.
You can design exellent hulls with pencil or computer..or a combination.
The PC is just another tool in the process.
I think it is worth the effort to learn some basic PC design software..but don't become its slave.

Tactic

[Sander Rave]

Hi Phil,

Some time ago we made a presentation on the same subject. It's way to big to post it here and the Dutch language may be a bit of trouble. If you like I can translate it for you.
The big advantage in my opinion is the optimalisation and precision of designing and engineering. Centre of weight and fitting of components can be calculated much easier and you don't have to do the whole job over and over again after changing the geometry.
Again, as Tactic describes, it's just a tool. It is a powerfull one though. Becomming a slave will be not much of a problem to you, as you seem to be a man of practice ;-)

I'd say give it a try and try to gather some people around you who use the same programs, to stimulate, and as a troubleshooting database
Good luck!

[JEM]

Depends on what your goals are.

My opinion:
If it's just for this one design for your own personal use, then spending money on software and learning it should be because you're interested in the software. Not as a means to get the design right. Seems like you're doing just fine without it.

Now if you have plans to sell boats of this design, or maybe the plans to them, then it would be worth investing in the software.

As said, software is a tool. It's no substitute for hands-on building.

[PAR]

The big advantage computers bring to the table is the ability to make a change, quickly without having to redraw entire sections or sheets of plans. The effort for the initial design work is the same, but accessing and evaluating changes, then punching out a new set of lines, station molds or whatever is where they truly shine.

That said, lofting full size, a craft you intend to build has advantages, the computer wiz kids don't understand. While lofting a boat, you become intimate with the design, literally knowing every square inch, it's sweeps, curves and it provides a knowledge of the shape of the boat you just can't get any other way. I generally loft everything I build to gain this advantage.

Having a set of station molds erected on a strong back or keel, requires the computer folk's faith in their software. The same molds, lofted by hand will have been faired, also by hand and insurance of the set of lines not offering up a big surprise when the longitudinal pieces go on. I've found that lines dreamed up and faired by eye are sweeter then those generated by mathematics. Math based lines can be perfect and logical, but the beauty found in the shapes on a boat is not logical and a well honed eye wins hands down, be it at the drawing table or the loft floor.

[Thunderhead19]

Are we forgetting that building the entire craft inside the computer first can save quite a bit of swearing later on? This is certainly true for big projects. In two dimensional plans it may certainly look like you have enough room and have a locker door big enough for batteries (for example), but three dimensionally, it may be impossible to cockeyed-wedge the same batteries around a corner and through the locker opening. I think, though, on small projects using a computer doesn't save a person a hell of a lot over a pencil and paper. There is nothing....absolutely nothing that can be done with a computer that can't be done by hand. Jet aircraft have been designed and built without the benefit of a computer. A collegue of mine remembers calculating airframe stresses for the CF-100 on a hand-cranked calculator!!

[Phil Thompson]

I am very impressed by the replies, thanks everyone. From my perspective the computer thing is very interesting - I did an Autocad course years ago but the expense of building 6 metre prototypes (about $15000 Aus) has put a dent in my finances along with running our cruising yacht and getting racing dinghies for the kids - I wasn't rich to begin with and am certainly not now. I obviously married the right woman.

Be that as it may it seems as though if it is just for me I could get down on my knees and loft but to make plans I have to get a program. I have a pretty strict set of parameters I am dealing with - road width for trailering, height and weight and so have a pretty good idea of what I want. If I need a computer program it is to tidy up a concept, not totally develop something new.

I would be happy to type in lofted offsets to start with and then get a 3 d model. As for advanced hydroststics I don't care too much. Sideways hull shape stability doesn't mean much in cats - fore and aft is interesting but I don't really care for performance prediction. Developing interior flat panel parts would be great -bunk bottoms, furniture. I may want to sell plans so the ability to chop the hulls into sections/halves and have different areas with different laminates shown is vital.

So at the risk of asking the same question you guys have answered many times before - what is the cheapest easy to use software for my use? Vacanti looks okay but doesn't render too well according to my fiddling.

cheers again

Phil

[CGN]

really cheap??, download freeship for free and buy intellicad in this site for 80 bucks or something close to that, don't expect "super 3D features", but for what you are looking for this is a great bargain.

export sections from freeship and open them on intellicad and finish them right there and if you think to jump into rendering blender is for free and a new version is on work.

and don't forget to download Alibre xpress for free..this days it can't get cheaper than this...cheers!!

http://www.intellicadms.com/

[Phil Thompson]

Cheers for the advice. The Freeship looks good enough for me - it looks great. I wonder what the catch is. I guess it is easy enough to export into intellicad - will have a go.

Many thanks

Phil