Trimaran Design Concept with longer foils than the main hull

Bora, you didn't answer my pm or post in response on my thread but I really, really would like to know what I did to upset you?
Welcome back....

 

I sent you a PM

Check your messages, you probably wrote this as I was typing...

 

Found this old photograph of the first Wild Thing being built in strip planked cedar; Malcolm Tennant thinks about his first overlong ama design.

 

Thanks Gary for the photo of the wild thing. I remember in the past seeing a colour photo of a completed wild thing, it may have been a sea spray magazine. I think it may have been the canadian one.

You must have a wealth of photos built up over the years.

 

Wow - such a beautiful boat! Is that the designer with the boat?

 

Richard,

Do you have something against catamarans?

Just kidding of course.

wayne

 

I can give you the integrand.

But, you have to give me the algebraic formula for your curves .... first.

:idea:

 

OK,

How many times will you be asked for your SOR before you finally come up with your requirements?

2 person?

10 person?

2 berths?

No berths?

All the data in the world will not help you decide what you want in general until you decide what you want in general.

I just read the thread (80 to 90% - some of it was long winded).

So, try it from this entirely new direction:

Pretend you walked into a huge boat show broken down into sub groups. You are not going to the monohulls, I got that.

You think you might be interested in a 30' tri, maybe a cat if you can figure out the differences, etc.

So, do you want something like a http://www.f-boat.com/pages/trimarans/F-22.html, or http://www.seacart30.com/default.aspx?pageid=15, or the wizard http://www.sailingcatamarans.com/wiz.htm with 6 berths at 25', or something else.

But, trying to learn calculus, naval engineering, fluid engineering, and terminology to decide what you statement of work might entail is a bit much.

Don't you think?

Until you know the general requirements the calculus is really not important, because you cannot really decide upon the algebraic representation of the curves you will eventually make in real life ....

Or, you are putting the cart before the horse, kind of.

Don't worry if every one does not agree with your requirements, you might have 10 kids, a wife, 2 exes, four dogs, and fifteen cats. So, what. But, if you really do have all that, maybe a boat is not what you need, but a shrink instead?



So, after all these pages, could you tell us what you would buy tomorrow if you saw it at your local boat show?

How many bunks, how many bathrooms (heads), with or without engines, got the sails, would a catamaran be a deal breaker, would a tri-maran be a deal breaker if it was 35'?

How sea worthy do you need, you only mentioned that in passing, and that is an important question.

Are you planning a crossing? Or, will you park it?

Does it have to be trailerable, or can you keep it at a dock?

Is this for weekends?

For fishing?

Or, do you want to go out on lake mead and have the girls laying out on the front deck?

What are your

3 main (must fulfill) roles?

How many will you expect for maximum occupancy?

Minimum crew?

Longest time at sea?

Shortest time at sea?

etc ....

wayne

 

Hi, Wayne, welcome to the thread

The gist of the thread is really supposed to be about the designs of trimarans with shorter hulls than amas. I was inspired by Gary B.'s Sid build but decided to start this thread because I am new and have a lot of questions about design that were not actually relevant to the thread. His thread was about an alternative to the Buccaneer 24. But his design idea for Sid - although he decided to build Sid a little differently, had included some cool stuff on how to make his boat more trailerable by turning the smaller amas so that they would be perpendicular to the hull for carrying on a trailer. Inspired by that I started thinking about Farrier's amas, and then about slide in/ slide out amas, and then I thought, what about longer amas and a small hull - what is the difference between shorter amas and longer amas and is it feasible to have longer amas and to trailer them with the main hull separately. So, yes, in terms of an SOR, I most likely have got my cart before the horse!

When I created the thread, I was thinking comparatively - not specifically. My thinking in asking for thoughts and criticisms of the potential merits for that kind of design are very open. It would be cool to discuss not only boats that have already been built - such as Wild Thing, but prospective designs of members other than myself. This was really meant to be a more general discussion of the type of design as opposed to a discussion about one design in particular.

I like to learn about new things, and I tend to model things in the process. So, in order to learn more about the design, I just roughly sketched out an idea in words in my first post. I don't really know that much about boat design but I am trying to design something we can discuss - which probably is a lot to do for a new guy like myself. I have had an interest in learning better math for a while, and periodically, I try to get better at it and use what little I know so I don't end up forgetting it all. Ergo, the math is rather challenging, but it was already on my agenda by itself - it just helps to have something to use it for

In the meantime, this thread is not about a specific boat, but about a type of design, so feel free to discuss this type of design! It would be appropriate, I believe, to even look at the SORs for designs built like this and to discuss how the designs worked, etc.

The point I am trying to convey is not to feel like the topic has to revolve around an idea I just threw out there as an example that I haven't even fleshed out entirely. It is just an example.

 

PS - the Wizard is interesting because it seems to have a lower cockpit, but it is a catamaran and doesn't really fit the design type. But those were nice pictures!

 

Boradicus,

Maybe not having SOR's for your needs is why it took this many pages to admit that?

 

Maybe updating the instruction set would help....are you still trying to do the math in cubits or are you going metric or imperial?

 

It sounds like you are interested in having a pseudo-design coffee house endless discussion about nothing specific. This kind of random follow-the-tangent conversation can be frustrating to people who put in effort to give you quality answers.

Here are some guidelines for quality interaction with design professionals:

1. Have a clear, specific goal you want to reach. You should be able to communicate your goal succinctly and effectively before asking questions
2. Do your own homework and answer most of your questions yourself. Wasting people's valuable time makes them less interested in helping the next person - who may be sincere about thier intentions
3. Clearly identify if the discussion is theoretical or if you are actually intending to execute
4. Clearly outline time frames, budget and project scope. If you haven't got the budget, resources or intent to execute make people aware before they invest in reading your threads

Please note this is not a negative attack or indictment - just a positive, supportive attempt to reduce the frustration you've been feeling about people on the forum.

--
CutOnce

 

Thank you for the feedback. Now I understand why everyone thought I was intending to build a boat on this thread better. Although I have seen several project pages, I had not realized how important it was to specify directly whether the page was about a project or for general discussion. I apologize to all for the ambiguities. I had thought that if I ever began a project that it would be great fun to begin building a thread, having seen other people's projects.

As far as the thread being 'non-specific,' certainly that was not the intention; I have read other threads on general topics such as the one on multihull-collision-survivability, and I thought that the generality of the subject matter of a trimaran with longer amas than hull was similar in its style. This is, actually, my first thread here. I have been learning, and I think that is important. I have also looked into and invited others to comment on different design considerations that might come up when thinking in terms of a shorter main hull, such as how turning, capsizability, structural durability, etc. Would come into play.

If you have found this thread to be personally frustrating, then I humbly apologize for it having taken up your time.

Nevertheless, this has been a good learning experience, and especially learning about SORs and how needful they are to the process of design when one is ready to design.

The multihull-collision-survivability thread, began similarly with a theoretical design that was posted by Skint For Life. There was what I thought was a basic SOR, and a few sketches, and the idea was focused on a single aspect of design: collision survivability. I got a lot out of reading his thread!!! When I posted this thread, I had it in mind to have a similar thread to that one but about a different subject.

I thought, as well that the main point of the forum was to talk about boating and have fun! I understand there are a lot of naval architects here - more so now than when I joined and started my thread - but other than stating that one of my objectives is to learn I haven't asked anyone through the thread to actually help me design or build a boat - and I have been most grateful for everyone's contribution - they have been most generous with sharing ideas, helping to clarify things, etc. Perhaps some of this did come as a result of thinking that this was a boat build, and my lack of realization that the whole topic of creating an SOR had to do with a boat build and not a idea like Skint For Life's Kung Fu Cat/trimaran.

I have learned something from everyone here, and to me, that may be more important overall than having a nice shiny boat just built!

Thanks to all!

 

Splines

Ok, after discussing SORs, and if this is a specific boat design or not, I kind of feel like my looking into splines as a design strategy really should be moved elsewhere, due to the fact that although it is something I looking into as a result of this thread, that won't be actually pertinent to it until I can get some actual hull configurations put together so as to look at them and see if there is anything to be learned there. I have read about wave modelling software, but I'm not there yet, and I don't know if the software is free or if it is cheap to buy I just learned how to connect two Bezier curves together, but I have not figured out how to avoid discontinuity in their curvatures. I think I should move this discussion on splines and mathematical hull design to another thread after this post, but for any who may be interested I will post the link to the new thread when I am ready to continue.

Thanks!