Exploring another idea

It is unfair to accuse Ad Hoc of elitism. He leads the horse to the water, not force the horse to drink. I have followed his posts and given the right questions, he has enough materials to pull up his sleeve to educate but you do the learning. He is humble enough to acknowledge other members who are experts in their field or even do homework of students.

Other members have also given you the the right directions. Petros, post no. 3 "you have overlooked something: four small pods of the same volume (displacement) will have much more surface area than one large one. So skin friction drag will be higher."


John Perry post no. 5 "As AdHoc will tell you, the advantage of a SWATH is superior seakeeping, it is not a particularly low drag hull form."

Gonzo and FMS gave the correct advice.
"Laymen usually feel insulted because they don't understand, even though they don't want to spend the time doing the math. Design has a lot of math. A lot of it is simple, like weights calculations, but very tedious. Are you willing to take the time to follow the steps necessary to learn to understand the answers?"

"It's easier to measure how a specific design fulfills specific requirements than speculate on an idea in isolation. You have an idea and no specific requirements to measure against."

This is a forum where you can get the best advice but if you easily get insulted or refuse to follow where they are leading you, we will get nowhere and the thread will die due to lack of direction.

 

Patient: But Doctor, I just want to know if I have cancer or not.

Doctor: Yes, of course. But before imparting such valuable information, I must first be assured that you can at least grasp the entirety of my diagnosis.

Patient: A simple yes or no will do.

Doctor: Yes. Yes. All my patients say this at first. However, in the end they refuse to believe what I have to say simply because they cannot begin to comprehend the entirety of the thing that has taken me decades of medical school and practice to discover on my own.

Patient: But that's why I came to you in the first place, because you are a doctor and I'm not. You see?

Doctor: My good fellow. The body is a complex organism and medicine is a learned science. Whether you have cancer or not is simply irrelevant. What is relevant is whether you are worthy of having cancer at all!

Patient: Do you mean that I really don't have a right to ask if I have cancer or not in the first place?

Doctor: I am merely suggesting if you really want to know if you have cancer or not, read these volumes. And, if I should discern that you have indeed grasped a rudimentary understanding of medicine, then maybe, just maybe I will finally give you my diagnosis.

Patient: Gee, Doc. I don't know how to thank you. I can only hope that I can prove to you that I am worthy of your knowledge before I'm found dead.



If ever you take the time to read any of the posts I have started, including this one, you will see that I have never once become defensive about a criticism or a rejection of any of my ideas. Not once. I respect the opinions of those who answer respectfully. I don't need to be lectured. I encourage discussion and ideas. And that's about all I have to say on this subject. The whole thing has turned me off of this Forum which I had always held in the highest regard.

If apologizing to AdHoc for mischaracterizing his remarks (maybe he had an off day), will put an end to this quibbling, then in the spirit of moving forward, I apologize.

Now, can we either dismiss this whole post as a blow or get back to the topic? Please.

 

Stay

Please don't leave, I too grew weary of the naysayers here, I left regular activity for a few years. But I am back for the gems and the occasional "Ah ha" moments I used to enjoy here. If you leave the trolls win!

We need new ideas in spite of the fusillade of inexpert criticism and eventual insults. The new Carbon/Cat Sailing races are a fresh breeze into that old tired America's Cup artifact. This field we are in has more rules to break than any other. Its been too traditional and romantic, time to shake it up.

 

Ill stick around for sure. A little argument doesn't bother me. But I have to read that damn book now.

 

If all the volume is immersed at rest, how do you propose to get stability to withstand rig forces? Hydrostatic stability relies on having volume which is not immersed at rest.

 

This type of hull idea has been done before, many times in fact, and with many variations.

Your analogy of a swimmer is not relevant to a boat design like youve drawn - why? Because a swimmer has almost 100% immersion anyway, by diving under the water, the wetted area doesnt increase by much at all, but you eliminate the wave drag and splashing etc. A boat isnt like this, in that i mean a submarine hull has around 40% more wetted area compared with a semicircle section surface riding hull, assuming both have the same displacement.

The main driver of SWATH type hulls, or underwater lifting bodies type hulls etc is not to improve speed or effiiciency, but to improve seakeeping motions.

Your original idea, as its drawn, wont work at all.... build a model and it will help you visualize... it has very little static stability. Add a small force from the sail, and it will sink that side. Before you even get the sail up, just boarding the boat from the dock will see it flip over when you stand on one side of it. See where this is going? There are ways of solving these problems, but you end up back at where ADHOC left you, where are going with this and what is the design goal? You need to know this before you can make teh changes required to make it work, or realize that its not feasible...

 

That all makes perfect sense and I'm embarrassed that I overlooked the most obvious point. Duh! as they say. I was so focused on moving an ideal bulb shape that I completely ignored the stability issue.

Maybe there are ways around it. But it seems there is no getting around a foiling trimaran or some configuration like it for a combination of speed with some stability. If only there was a way to right them after they capsize.

I'll think more on this idea. But it's looking like another dead end. It appears that in boat design, there is truly nothing new under the sun.

 

Indeed, its basic naval architecture:
http://www.boatdesign.net/forums/sailboats/perils-edgy-design-offshore-38903-10.html#post476845

But no matter how many times it is said, generally by those stating as such, believe it with such passion far beyond logic and wont be swayed that it is not new, ergo their belief is greater than science...and then we're into the realms of 'religion' rather than science and it's open season

 

Let me rephrase. I did think about stability by using the same type of rig used by speed rocket. I didn't think about each bulb having the same volume. The port and starboard bulbs would have to be larger increasing drag etc etc.

 

Exclude me from this generalization.

 

It's amazing how easy it is for people to get the central point, once it's clearly stated without any attempts at being "Socratic", and without any attempts to create rabbit holes to lead said people down.

Just saying. In case it may be relevant to some members.