Good reasons NOT to design

[catsketcher]

Hello all,

This may stir up a hornets nest but it seems as though there have been more than a few posters who have little experience in sailing or building who want to design a multihull. The internet demands respect for others opinions but I do feel that advice needs to be very carefully considered.

I just posted a quick reply on beam theory and then started thinking - What if someone goes and uses this post to do something silly? Should I encourage people with little experience to try something I find very tricky with decades of mucking around with boats? On the other hand I am very interested in loadings on multihulls and welcome input from others.

I certainly do benefit from the experience of other members of the forum and I hope that I help out when I can but I think there are more reasons NOT to design a boat than there are to design one.

The best reason is that someone has done it before. There is such a wide variety of craft that there is almost certainly a boat close to what you want. Buying or building one of these has to be easier than designing your own. I really feel that it is only after having a boat or three that you develop an idea of the deficiencies of the type and then youi may have a worthy contribution to make. On of my favourite designers is Jim Brown who said "a designer is nothing but a builder who draws " (or something like that)

For myself the only reason I designed a boat at all is that I came up with an idea that no one else was doing. It has been a major learning curve, has cost me heaps but has been rather fulfilling. It has used all my experience in building and sailing to produce a good craft.

I would be interested in hearing from others on the forum about helping people with little experience when they really may be far better served by no help and a gentle shove in the direction of a marina, sailing school, boatyard, sailing school or the like.

cheers

Phil Thompson

www.foldingcats.com

[hansp77]

Hello Catsketcher,
I think you will find that most advice here from the pro's to the noobies is pretty much what you said.
The flavour of most advice I have read is to first, learn to sail, own boats, fix boats, and then last if you still want, learn to design and build boats. And if you are going to design and build boats then start small.

[nero]

Relative to size.

It is true that designing a multihull is complicated. There is little data for cross deck structures.

As hansp77 states start small. And for a small boat design anyone motivated should arrive at something. May end up being just a learning experience. (I guess that is a reason to design)

Time is the best reason not to design. It takes a long time to figure it out. I never have completely, so I am building what I have and then solving the tangible problems.

It also makes the boat building process less fun and longer.

[Toot]

Originally Posted by nero

It also makes the boat building process less fun and longer.

That's a matter of opinion.

Boat design has a language all its own and I've discovered, by-and-large, this is for good reason. When I was building my first aircraft, I heard many times over- if you want to fly a plane, building it yourself is *not* the way to go about it- you've got to want to *build* it... and view flying it as merely the icing on the cake... And that's leaving alone the matter of actually designing it!

I think prospective boat-builders are enthralled by a boat's relative simplicity. If a ship won't be called on to endure the rigors of a trans-oceanic trip- if it's simply intended to be plopped into a relatively small lake for a few hours spent cruising within swimming-distance of the shore, then designing and building a vessel isn't really such a complicated task at all. So, foremost, I think people are seduced by the simplicity of boats. What most professional designers/NA's/etc understand is how to optimize the designs and make them safer. This can be extremely important, but the bottom line is that, at its essence, a boat is a simple device than can be hacked out with little more than a couple of 2x4's and some glue.

For those who want a good boat, or a cheap boat, plans are the way to go. But for others, self-designing may be less intimidating- especially for a first build. Not everybody grew up near a lake or river with lots of boat traffic. For these people, the act of struggling to understand how things *might* be done, may very well make up for the years of knowledge that could/should have been gleaned through the seeing such craft in action for the better part of an imaginative youth. These kind of information can be gleaned, certainly, by buying and operating a boat for a few years- but struggling with design aspects brings that information home quite a bit more clearly. There are so many complex relationships that don't ever come to mind until you've endured the design process. Even builders, let alone operators, can't appreciate the complex tradeoffs that a designer has to face. For this reason, designing, and trial by fire (building it and floating it), definitely will teach you the most in the shortest period of time... It's merely a different path- obtaining design and construction skills ahead of operational/maintenance skills. Nothing wrong with that so long as the design aspect gets you more excited than the boating aspect.

The other part of this is that some of these people (myself included), may not even know if we care for boating. But we already know that we love designing and building things. So if I design it and build it and it floats or sinks, I can look back at the things I learned and the time I spent and view it as worthwhile.

So the question to ask a would-be boat designer is this: Are you more excited about designing and building a boat? Or by the thought of using the boat to go places and do things. If the former, then designing, even a first boat, is clearly the way to go so long as you don't bite off more than you can chew. Don't set out to design the next Titanic or Queen Mary, or even the next Miss Budweiser. And that deisgner/builder then has two choices- tread only where others have gone before and play it safe. Or accept the risk that your contraption may be the newest dive wreck off the coast of wherever. So long as you are okay with one or the other of those options, design away!

Personally, in my heart, I am a designer/builder. If given a choice between designing and building stuff for the rest of my life, or getting in and driving/flying/sailing stuff, I'd choose to design and build stuff- that's my preferred profession and it's my preferred hobby. If my aircraft flew well, but I never personally got off the ground in it, I would be happier than if I'd simply gone out and bought a plane to personally fly around in. It just depends on where your heart lies...

To put it another way- in some people's fantasies, they are Gene Kranz rather than Jim Lovell. Those people are not common, but they do exist.

[frosh]

Hi Phil, I am so pleased that you posted this item as we are seeing a fair number of people that have very little experience of even what a boat should look like, that post a basic rendering from " Freeship " or similar and suggest that with a little help from this forum it will be self designed and built.
This is always the pregrogative of the individual of course, but for those that give advice here it is necessary to first point out the likely pitfalls before offering further encouragement.
What I find a bit alarming is that generally the project is not for a dinghy but a live-aboard for cruising in the open sea or Great Lakes. The chance that human lives are at risk based on a flawed design inevitably striking bad weather eventually is unacceptable if it could have easily been avoided.
Toot gives us the viewpoint that for some, including himself, the self design and build is the main fun and the use of the finished item is secondary. This is entirely reasonable but I can't agree with the following however : QUOTE: But for others, self-designing may be less intimidating- especially for a first build. Not everybody grew up near a lake or river with lots of boat traffic. For these people, the act of struggling to understand how things *might* be done, may very well make up for the years of knowledge that could/should have been gleaned through the seeing such craft in action for the better part of an imaginative youth.
Phil, I agree that the best reason for self designing is for some one with sufficient knowledge and first hand experience to create something that is different to what is in the market place already.
My last three projects were: (1) 6 metre tandem sailboard. (2) Two person outrigger paddling and sailing canoe. (3) 5.6 metre high performance trimaran, incorporating planing amas. There are no existing plans anywhere for any of these, as far as I know.
This now makes about 10 boats in total of which I designed about 5.
I have been sailing for nearly 40 years and reading technical books on the topic for even longer. I accept the possibility that sometimes the finished boat might not perform as I planned, but using them in protected water means that even if the worst happened I and my crew are not putting our lives at risk.

[Thunderhead19]

Psalms 107:23-27 - They that go down to the sea in ships, that do business in great waters ....blah blah blah blah.

I dont remember exactly how it goes, but the upshot is that its basically encouraging men to do dangerous things (certainly it WAS a dangerous occupation at the time of the writing).

[nero]

Stepping back and understanding what this thread is stating is a bit condesending.

Everybody who wants to design a boat of any size should be encouraged to try. This is the best way for someone interested in a boat to understand as well as comprehend what a boat could be ... or can not be.

If they have not the talent, skill, intelligence, or education to do so they can at least approach a professional with some understanding of their ideal boat. Even if they succeed to build something that doesn't float as they envisioned they will gain wisdom.

And I agree, the first step is to try and find plans for a boat that has been built before ... if one can afford them. And true some (most) people starting out have no clue of what a catamaran is and isn't. Working on a design, frustratingly points out the constraints and conflicts of bridge deck cat design. But even if they never finish their design, a pro can have a better idea of the clients vision and not just his.

Perhaps the worst part of multihull design is the lack of published info. The pros do not or can not publish a book or web page explaining how to's or calculators.

As an amatuer, I hesitate to asked a NA to proof and correct my design because, I have heard that he then becomes the owner of the design.

Incedently, I got entangled into the design process because I could not find plans from a NA that were affordable. The only plans that were interesting were for a harry proa. I went to look at one being built. Passed several emails to Rob Denney. And decided there was not enough interior space to live aboard (for me personally)

[antonfourie]

I think that main thing is that you should never underestimate the danger of inexperience, and should encourage people to adhere to good practice and proven scantlings and standards.

[dem45133]

Interesting... as I am one of the newbies this thread is directed to.

A couple of thoughts...

1) As I mentioned.. I do not have the right to risk the lives of my family and friends ...and won’t... I think that needs to be stressed to all us newbies... I already have the belief... not all do... and many overrate their abilities too easily.

2) 90% I believe... are, like me, bit by a sailing bug from some event or exposure... and while we've been on the water in other small craft want more. The "more" is typically predicated by exponentially increasing costs with each 5 ft of centerline... and since most of us haven't won the lottery... but are somewhat handy... we start looking at alternatives.

3) Some, like me, are very detail and precision oriented. I think this is another item that has to be stressed. If one does not possess these traits, they probably should not be involved in designing or building anything that other lives are dependent.... feeds back to item 1.

4) I think that most newbies that would even consider such an endeavor, like me, are fairly imaginative, creative, and entrepreneurial... which when combined with #2, start us thinking in an "alternatives" mode. Thus my inquiry into a monohull conversion. We also get an enjoyment in doing something most either can't or won't. Myself personally, like things that are different. If everyone has a certain thing... I likely do not want one... but I love things that are unique and different.

5) There is a list presented by EAA to prospective homebuilt aircraft builders...(I'll post it if I can find it) that tests their skills, ability to learn, attention to detail, and their resolve. It would be equally applicable to design-builds or any builds on sail and power as well. Now EAA has a extensive support structure to help all builders. One difference though is readily apparent.... most are plan or kit builds... someone else has proven the design (generally).

6) It is an unfortunate fact that as soon as "aviation" or "marine" is attached to any device...the cost just tripled or quadrupled. On some items this is necessary for redundancy and reliability... but it carries over into everything (from my observations). Parallel to this thought thread is the more practicable idea of buying an older vessel and bringer her up to snuff… Many have an attractive price but need re-powering. A new 25 or 35 hp engine for my tractor would cost significantly less than the same exact engine set up in a marine configuration. Now I expect some additional costs due to certain upgrades etc for reliability, and exhaust cooling…. But, as in aviation… I think (although I may be in error, there is a “non-necessity-play toy-rich man’s sport” premium automatically applied. There are likely some economies to scale effects that hold prices high too. For what ever the reasons, since I am not a rich man… I tend to think in alternatives. I am seriously considering an automotive or agricultural engine conversion… maybe the Volkswagen rabbit diesel if I can find one… or just stick to gasoline (which really has no business in a confined space… i.e. boat of any kind in my mind) and adhere to the due diligence of ventilation and inspection at all times.

7) I think is dangerous for you experienced people to hold back. Yes, I am sure the experienced old timers in the subject may get tired of the same questions being repeated in what I would suspect is an annual cycle (as once a thread is sufficiently old… it’s not seen readily and only shows up on a search)… maybe one of you could place (may have already and I haven’t stumbled on it) a list of “dos and don’ts” and “ your really need to consider” non-reply-able threads in the beginning of the group subject. I’ve see other boards do that. Think back, what if some one with the knowledge hadn’t enlightened you… I am sure there has to be many cases where their knowledge saved our collective butts somewhere. I know its true for me. We have all been in that “know enough to be dangerous” category at times.

8) Please forgive our ignorance and propensity to ask the repetitive “stupid-obviously ignorant-on-the subject” questions. But every single one of us were all ignorant of whatever it is we didn’t know… fortunately, there was someone willing to listen and set us up with direction and knowledge. I, for one, am grateful for them and thank them. While I am formally educated and possess a masters level education… the vast majority of the knowledge I have gained in life was from self study and asking questions. One of the things I am proud of is that I have never stopped learning (with the possible exception of typing) and have never stopped being inquisitive.

9) Please be patient…it is your inputs and advice that also prevent us from letting wild hairs get too wild (yea, its takes a few years for most of us to properly reign in the wild part… but where would we all be if there weren’t people like us… there would be no diversification, only one example of anything as no one would feel the need to build a different one… now that would be horrific in my mind.)

Since so many people take these boards for granted today and fail to thank their creators and participants, I want to THANK all of you and let you know that at least for this newbie, I AM appreciative.

Thank you,

David Mikkelson
Hillsboro, OH

[westlawn5554X]

For thousands of years sailor and boatbuilder have built boat and ship alike with hunch feeling and past experience, but present day equipment would ease the failure, so go out and buy a lifevest. Then built your boat.

Student

[kach22i]

Originally Posted by catsketcher

For myself the only reason I designed a boat at all is that I came up with an idea that no one else was doing.

www.foldingcats.com

1. Good reasoning.

2. Nice cat, interesting use of space.

[frosh]

Hi Nero, I disagree that the theme of this thread is in any way condescending! Any newbie asking for advice on this forum does not have a right to get an informed wise answers even though this is what does happen in 98% of cases.
Remember that if any newbie wanted high quality design or building advice he or she could readily obtain it with a high degree of reliability by commissioning a NA or yacht designer.
I would say that experienced people which includes many that do this thing in their jobs for a living and therefore a considerable fee, love to give of their time and knowledge for free on a forum like this to those genuinely interested in boats but needing help.
The other side of the coin is that when a newbie states that they want to design a transatlantic multihull and build it for a budget which would only really cover a good quality off the beach catamaran it is incumbent on those much more experienced people who have already gone through the exercise, or very similar to speak up LOUDLY and tell it like it is.
Dem, I liked your well considered posting and has many, many valid points.
What is apparent however that some newbies make postings about almost identical requests to thread contents that were discussed at length within the last couple of months. Without meaning to discourage anyone at all from posting, as the more the better, checking some recent threads for an hour or two beforehand would help every one.

[Toot]

Dem- I don't think this was *exactly* what you were looking for, but it comes close to the mark. From the EAA... With appropriate adjustment, it could be applicable to boats as well.

As for the cost of aircraft components, I can tell you, having worked as an inspector for new and used aircraft parts, the inspection and, especially, the documentation process is hugely important and costly. Everybody who touches any aircraft part, documents it, visually inspects it, maybe tests it, and then checks all of the paperwork going back from him to the manufacturer to ensure that everybody who had the part at any time has documented it appropriately. If not, phone calls are made, and the part doesn't move until they hash out what the heck happened. Sometimes, it's just a stupid typo made a few years ago... but one little number being off, can tie things up for days or weeks, or turn the part to scrap if the error can't be corrected. As you can imagine, just the act of inspecting the paperwork can be daunting if a part has changed hands a bunch of time... And, of course, this is all being done by a reasonably intelligent (or at least not retarded) A&P who gets paid for his time.

The bottom line is that it's the man-hours that goes into ensuring the lineage and paperwork trace and originality of the documentation for the part that adds greatly to the cost. Unfortunately, it's a viscious cycle. Because these constant inspections add to the cost, people may attempt to sneak in counterfeit parts that can be made for a tiny fraction of the cost. This risk (and it has happened) means that the inspectors/testers have to be extra vigilant... which then adds more to the cost, which makes counterfeiting more lucrative, which adds to the cost and paranoia-level during the inspection and so on.... Rinse, lather, repeat.

EAA’S HOMEBUILT AIRCRAFT BUYER’S CHECKLIST:

THE ESSENTIALS

A primary mission of EAA is to encourage the safe construction and operation of experimental amateur-built aircraft, known informally as “homebuilts.” One of EAA’s most fundamental elements in this mission is promoting informed builders and buyers.

The decision to purchase a homebuilt aircraft or kit can be a daunting challenge. There seems to be a full range of behaviors with which people respond to that challenge. On the one hand, the numbers of envisioned risks and questions to be explored might come to seem overwhelming, so much so that the task can become endless, never reaching a conclusion. That’s disappointing, and probably not really warranted. Not all questions can be answered up front; many will be resolved as a project unfolds.

At the other extreme (and perhaps more dangerous) is the chance that a potential buyer/builder will be driven exclusively by the emotional appeal of a given design to the extent that important practical issues are never addressed, much less answered. The answer lies somewhere in between – but how does one find the right formula for his or her own decision-making process, particularly when one may be new to the homebuilding movement? In general, it is a good start if one, at least, knows the questions. Answers will come and EAA is one good source.

Since its beginning in 1952, EAA has witnessed an explosive growth of homebuilt activity, and an expanding industry that now offers over 700 designs of kits and plans-built aircraft to eager customers. Amateur-built aircraft have come to comprise over 15% of the registered U.S. civil, single-engine general aviation fleet. Most of the activity is now concerned with construction from kits, and more and more of the kits offer high performance, sophisticated designs. Prefabrication, reduced construction times, and ease of the building process have become advertising hallmarks for many kits. Significantly, an increasing number of these aircraft are being acquired second-hand from the original builders.

It is a very different climate for the prospective buyer/builder than could have been envisioned even 10 or 20 years ago. Two key measures of the continued homebuilt community success are the safety record (particularly the first hours of flight) and the completion rate. Both measures can be improved by all potential builder / owners carefully considering the advise in this material.

To keep homebuilding a safe and satisfying pastime, prospective builders and/or buyers of aircraft, plans, or kits to be registered as experimental amateur-built should be more than minimally knowledgeable as to the suitability, performance, and track record of the aircraft that attracts their attention. Buyers have the right to expect that designers and kit manufacturers will accurately and objectively aid them in developing the requisite knowledge.

The potential list of information to be gained during the decision-making process can be long and varies by aircraft design. The EAA Homebuilt Aircraft Council has attempted to sort out those aspects that seem crucial and most applicable to the wide spectrum of customers and products. A generic checklist has been developed consisting of a series of questions, which should be considered while reaching a decision to embark upon the purchase of a given aircraft or project.

Fundamental to considering the purchase and/or construction of an experimental amateur-built aircraft is an understanding and observance of the regulation that makes possible FAA-authorized inspection and certification in this category (FAR21.191(g)). In simplest terms, the regulation states: (1) that such aircraft must have been constructed with the sole intent being the education and recreation of the builder or builders, and (2) that the builders must have executed the majority portion (at least 51%) of the construction of the airframe (that is, excluding engine, propeller, avionics, upholstery, and paint). FAA Advisory Circular (AC 20-139) reaffirms the intent and legal basis of this regulation. EAA advocates the true intention of this regulation and believes that kit manufacturers and customers have a shared obligation to observe, promote, and protect it.

The Checklist:

1. Do I understand the legal and regulatory provisions under which experimental amateur-built aircraft can be constructed and operated?

• Do I understand FAR 21.191(g)?

• Have I read FAA Advisory Circular AC-20-27 on Certification and Operation of Amateur-built Aircraft and AC-20-139 on Allowable Commercial Assistance?

• Does the manufacturer of the product I am considering comply with and promote the educational intent and provisions of these documents?

• What are the policies and capabilities of my local FAA Flight Standards District Office (FSDO) concerning homebuilt aircraft?

2. Can I afford the aircraft or kit in questions?

• What is the estimated full cost (including taxes, shipping charges, tools, and other indirect costs) to complete construction?

• What is the additional cost of engine, propeller, paint, and avionics that are most appropriate to the mission design of the aircraft?

• What other “aftermarket” expenses can be anticipated? Are there readily-available sources for ancillary parts?

• Looking farther ahead, how about the availability and cost of insurance, hangar fees, inspections, and operating expenses?

What is the cost of desirable builder workshops or legal builders assistance?

Do I have adequate space and facilities necessary to complete and house the project? For example, will it require a machine shop, ventilated workspace, a heated garage, a hangar, a trailer?

Do I have family support for this undertaking? Do I really know the depth or durability of the commitment?

Can I build it?

• What skills are required? If in doubt, shouldn’t I try them out, for example, in one or more EAA SportAir Workshops? Is there local assistance available through a local EAA Chapter and EAA Technical Counselors? How about knowledgeable friends and acquaintances or local mechanics?

• Are building instructions clear, complete, and up-to-date? Do they include instruction in best practices and quality control?

• What is the reputation for the manufacturer’s support during the construction and early flight phases?

• Does the manufacturer provide direct after-sale builders support, or is there a reliance on user clubs and e-mail exchange groups to communicate supplemental information? Are such groups available, reliable, and effective for this design? Do I need a computer to stay abreast of needed information?

• Does any available “quick-build” option for the kit remain within the “51% Rule”?
Does the kit manufacturer provide documentation to that effect?

• Does the kit manufacturer provide a “builder assistance” or “factory workshop” opportunity? If so, is it truly geared toward thorough education of the builder/buyer as to construction techniques, quality control, structural integrity, and airworthiness of the individual kit aircraft, or is it a “front” for illegal “skirting” of the 51% Rule?

• What is the record of the completion-to-sales ratio for this model? How does that statistic hold up when compared to how long the model has been available on the market?

Will I have confidence in this project and the resulting aircraft?

• What is the record of the kit manufacturer regarding on-time delivery of kits, parts, and backorders? Is there a plan to protect my investment until orders are completed? Specifically, can I use an escrow account provided by the manufacturer or other entity to protect my payments?

• Is the financial stability and management of the manufacturer such that I can reasonably expect the company to remain in business – at least until all kit components are delivered, and hopefully until my project is completed?

• Are all parts and materials “aircraft quality?”

• What flight test and other data has the manufacturer verified and made available (for example, spin, structural loading, and flutter testing)?

• Were published performance data normalized to standard conditions? Are they complete and detailed?

• Are there authoritative flight test articles available for this type of aircraft (for example, CAFÉ data, EAA Aircraft Performance Reports)?

• Have I searched for accident data on this aircraft type? What cautions does this information suggest?

• Are there any restrictions or special requirements for insuring this type of aircraft? If so, what is the basis for them?

Can I fly it (and enjoy it)?

• Have I had a demonstration flight in this aircraft? Was it a thorough demonstration of the performance envelope of this airplane, did it reveal any unexpected or marginal characteristics? Did I fit in the aircraft? Will I be sure to have requisite training, licensing, and currency for this aircraft?

• Can I obtain appropriate transition training tailored to particular properties of this make and model?

• Is an FAA Inspector or Designated Airworthiness Representative (DAR) available to perform the final aircraft inspection?

• Will I be able to complete a thorough step-by-step flight test program under the FAA-required Phase I operating limitations for this aircraft once it has achieved FAA registration and final certification? Have I read FAA AC 90-89 on flight testing? Will I have an EAA Flight Advisor to help plan and assist in this phase?

• Will I, in the future, be able to have an adequate supply of the proper fuel for this aircraft?

• Will I be knowledgeable, skilled, and willing to perform maintenance on this aircraft, or will I require services of an A & P? If the latter, will one familiar with this type of construction be available?

Finally, looking beyond the esthetic and emotional appeal of the aircraft (and that may take some discipline), are my needs, resources, and skill level honestly compatible with its mission design and performance profile (for example, cross country vs. acrobatic vs. local sport flying)?

Many more questions can and should be raised – often specific to a given type. However, EAA regards the above list as fundamental and critical. While this list appears large – the answers ARE available! Help is abundant. EAA members, staff, programs, information, and services are equipped and created specifically to help you address these questions at the outset and as your project proceeds.

Failure to engage in an adequate consideration for any one item noted above could result in a less than satisfactory outcome. Remember, this is the start of a process that is meant to be educational and recreational, not necessarily expedient. The focus should be on the process that will ensure a quality final product and a well-educated builder/pilot – not prematurely centered on just the product itself. Remember too that as the builder/learner of record, only you (not the FAA, kit manufacturer, or plans designer) bear responsibility for that product.

All this may seem somewhat intimidating, especially when one is anxious to purchase or start building the airplane of one’s dreams. However, in homebuilding of aircraft, the real joy and satisfaction generally come when one goes about each task in a project with care and precision – and that holds true for the planning process just as it does for any other phase.

EAA wishes you much joy, success, and safety as you undertake your project. Remember to use the EAA and its programs as your guide and resource.

[dem45133]

Yes, it was similar to this. Maybe one of you old timers in the industry would want to adapt it. I will later if you want.

Oh by the way, I do understand the traceablity/accountabilty necessity in commercial aviation... experimental is a little different I think... maybe not now... haven't looked in a few years. Counterfieting was a problem then too.

I guess today's "suit-happy,I'm-not-responsible-for-anything-that-happens-to-me" world... has affected the marine manuafactures too. A good amount of their product pricing likely reflects recovery from lawsuits or the prevention of one.

Chaulk it up to the fact that somehow I seemed to have gotten off the escalation wagon circa 1970... although I can easily estimate about any project with other people's money in today's dollars quite well... its just numbers... I still seem to get sticker shock when its my money for some reason.

[Figgy]

"If at first the idea is not absurd, then there is no hope for it" ~Einstein