Aggressive Mini Speed Boat Sketch...would it work?

[LilWake]

PS: I like how you keep editing your posts to remove and add comments that would have otherwise made you look like an ***. I wish I could have quoted you earlier.

 

[LilWake]

Put your drawing in a drawer, then once you have a grasp on the principles, mostly ignored in your sketch, open the drawer and look at your sketch. You'll find the same humor we find in it. We see this sort of thing often, outrageous thoughts, claims and shapes that can't be reconciled or supported hydrodynamicly or with reasonable engineering. It's like an airplane design without an understanding of aerodynamics. Lastly, you "sponsons" will just "trip" the boat in high speed maneuvers and once you've done this in real life, you never attempt to do it again, let alone design a boat with them on it.

PAR, this may very well be the case. The only problem with all of your posts is you're quick to point out all the errors but are offering no solutions. This is anything but constructive. Would you mind helping or are do you just a glass half empty type of guy.

I am on the forum to learn, but it seems some of you folks just like to deter guys like me who simply have an interest in this hobby as all of you once did.

 

[afteryou]

Hobby? more like a job I think.

 

[LilWake]

Hobby? more like a job I think.

Haha, You're right. It was once a hobby but some of these guys it's very apparent it's now a job as it's sucked them dry of any passion they once had, to develop, educate, and cultivate.

To most of you, I appreciate you sharing your constructive feedback, and potential improvements to this design. I'm still interested to hear from more of you.

Thanks!

 

[tomas]

PAR, this may very well be the case. The only problem with all of your posts is you're quick to point out all the errors but are offering no solutions. This is anything but constructive. Would you mind helping or are do you just a glass half empty type of guy.

I am on the forum to learn, but it seems some of you folks just like to deter guys like me who simply have an interest in this hobby as all of you once did.

I would suggest that you are misinterpreting the feedback you are receiving.

I was a fan of your build thread and I found PAR's comments to be constructive in that he's encouraging you to get a good grasp of basic hydrodynamic design principals first.

Yes, he and others posses the knowledge to give a detailed review of what's wrong but that would take more time than most are willing to unilaterally volunteer.

My suggestion would be to spend some months reviewing the vast number of relevant forum threads here. They are full of links and references to other sources of information as well. Many questions will develop in your mind as you do this, which you can then pose in a new thread(s), as well as the existing relevant ones. Iv'e noticed that no one objects to bumping old threads here as long as it's meaningful. This helps everyone here that wants to learn. This cycle would essentially be your educational learning curve as it is for myself.

Overtime, you will be ready to post your design spiral thread, which is iterative and focuses on correcting/revising all the basics ideas you have by asking pointed questions that would be educational for everyone. Then PAR and others can contribute their expertise because the responses would then be comprised of answering particular technical issues, instead of the broad critique of a particular design thumbnail that you've apparently requested. (You will also be encouraged to consult a professional $$$ as well)

Conclusion:
You are not yet ready to begin your design spiral is the gist of the responses so far. When your are and if you decide to do it here, the result is a true synergy that makes this forum such a great resource, a community effort which is a win-win for everyone.

 

[PAR]

This is precisely correct (Tomas). The level or number of issues on a design like that, are just too numerous to list, define or attempt to describe, let alone address in a meaningful way. Assuming the level of understanding, which is indicated by the sketch and it's "unique" features, simply suggests you have a way to go before "meaningful" lines could be self developed. On the other hand, you are at the point where a reasonable SOR could be developed, which will help define the goals of the project. This is the very beginning of the design spiral and the logical first step.

 

[WestVanHan]

Well then he can spend a ton of money in building it,a lot of time,and take it out to find it doesn't work well.

Hopefully we don't read about the Coast Guard's attempted rescue of him in the news....

 

[PAR]

Trust me, once he gets a handle on some of the principles in yacht design, he'll look back and laugh at this particular sketch. Now, he may cling to some of the styling, which I have no issue with, but the running surfaces are full of issues. I have an old sketch I did, many years (okay decades) ago, also by hand. It's a 40' sailboat of ungodly proportions, with an offset pilothouse and a displacement twice that of a George Buehler design. The appendages were fairly conventional, but the rig was absurd. I use to have it hanging on the wall, just to keep me centered.

 

[LilWake]

You guys are quite the extremists! It's entertaining actually.

I'm never going to study the principles of yacht design...because I'll never build a yacht. I don't know if you missed the 4th sentence in this thread, or if you just are so damn fixed or your big boy boats that you read 12m instead of 12ft.

This is a 12 FOOT boat. 8 cu ft of flotation foam would float it. I don't think anything too tragic will be on the news anytime soon, so don't get your hopes up.

Maybe this is why boats are so damn expensive is because they pay pessimists like you guys to axe 19 designs out of 20 because of your out of this world logic.

I'll continue what I do...think creatively, sketch my ideas, exchange these ideas (hopefully to inspire others or get inspiration from theirs). I'll enjoy it just as it is, one of my passtimes.

For you guys, you can continue to do what you have always done; the same thing over and over and over. Because what's tried is true, and you're sure to never fail that way.

 

[IMP-ish]

Sad fact is there are very few boats designed totally different that work out.
Most companies start with a proven hull and make small changes to try and improve things they don't like or reduce weight.
I'd like you to prove everyone wrong and do something totally dramatically different and you will get celebrity status Only 1 of 1000 make it that way.

 

[afteryou]

Sad fact is there are very few boats designed totally different that work out.
Most companies start with a proven hull and make small changes to try and improve things they don't like or reduce weight.
I'd like you to prove everyone wrong and do something totally dramatically different and you will get celebrity status Only 1 of 1000 make it that way.

Well said.

 

[LilWake]

There are too many who are scared of those odds.

I would build a boat like I drew because I am not after 100% efficiency or 100% function. If it floats like a boat, and is fun to drive, then it's a success to me. For me form is equal to function.

I'm not set out to break any records, just trying to break the mold.

 

[tomas]

You guys are quite the extremists! It's entertaining actually.

I'm never going to study the principles of yacht design...because I'll never build a yacht. I don't know if you missed the 4th sentence in this thread, or if you just are so damn fixed or your big boy boats that you read 12m instead of 12ft.

This is a 12 FOOT boat. 8 cu ft of flotation foam would float it. I don't think anything too tragic will be on the news anytime soon, so don't get your hopes up.

Maybe this is why boats are so damn expensive is because they pay pessimists like you guys to axe 19 designs out of 20 because of your out of this world logic.

I'll continue what I do...think creatively, sketch my ideas, exchange these ideas (hopefully to inspire others or get inspiration from theirs). I'll enjoy it just as it is, one of my passtimes.

For you guys, you can continue to do what you have always done; the same thing over and over and over. Because what's tried is true, and you're sure to never fail that way.

Since performance at wide-open-throttle is part of the enjoyment of a small craft like this (I like speed and acceleration), I would ask myself a few questions such as:

How fast will it go?

What happens when suddenly turning hard to port or starboard at WOT?

What happens when a large wake or wave is crossed at WOT?


I don't know enough to even pretend to predict the answers by looking at your drawings but I was looking forward to learning from your process how to be able to do so, since the hull you've depicted is very different from that of your build project.

I'm sure that it will float. It's the dynamic response/performance that I'm curious about.

 

[PAR]

There are too many who are scared of those odds.

I would build a boat like I drew because I am not after 100% efficiency or 100% function. If it floats like a boat, and is fun to drive, then it's a success to me. For me form is equal to function.

I'm not set out to break any records, just trying to break the mold.

It's not the odds we're scared of, it's the potential serious injury or worse that has us concerned.

It would be one thing if you had a highly stylized, if rather conventional under belly project (the size is irrelevant). Some level of success could be assured. Even if you made a few, possibly odd changes, just to see what happens. So, maybe she wouldn't turn so good, or run as fast as others of similar size and power, but who cares, you're having fun.

That's not what your sketch shows. You sketch shows a ventilated running surface, with a questionable location and shapes. No weight or moment study, so just a crap shoot on the CG and CB, both of which will be critical in a boat scooting along at speed. The sponsons are a sure fire tripping hazard and frankly the first turn at speed will dump the skipper in the drink, possibly with enough force to eliminate further experimentation. I've tripped boats, rolled them, capsized a few, had them swap ends because I drove over the CG and even pitch poled one. I lost a friend last summer when his race boat drove over it's CG (as a result of a wake) and he pitched, then was tossed out and run down. It happens on a fairly regular basis. Even highly refined designs can get "caught" with tragic consequences, just watch any powerboat race on TV and you'll see a few, that just got unlucky. Couple this with a design full of "issues" and the best advise would be, to make sure your insurance premiums are up to date.

This doesn't mean don't try, but it does mean don't try all the ideas all at once. First off, you will not learn anything, because you will not know what did what. Design a fairly conventional shape, maybe with a step, or a deep forefoot, then try it out. Play with the step location, depth of the forefoot and see if you've gained or lost. Skip the sponsons, you're just going to rip them off in a turn or trip the boat, neither of which is desirable. As you learn what works and what doesn't, you can expand the design with other ideas and contrivances.

I say go for it, but use a less daring under belly at first, so a reasonable level of success can be achieved, right out of the box. As you add and subtract stuff, you'll know which is doing what to the performance envelop. For what it's worth, you want a clean, unobstructed under belly, with the least amount of protuberances and drastic shape changes. You don't want anything in the water that doesn't absolutely have to be there. Anything that does live down there should be aligned with the flow and as diminutive as possible.

 

[LilWake]

It's not the odds we're scared of, it's the potential serious injury or worse that has us concerned.

It would be one thing if you had a highly stylized, if rather conventional under belly project (the size is irrelevant). Some level of success could be assured. Even if you made a few, possibly odd changes, just to see what happens. So, maybe she wouldn't turn so good, or run as fast as others of similar size and power, but who cares, you're having fun.

That's not what your sketch shows. You sketch shows a ventilated running surface, with a questionable location and shapes. No weight or moment study, so just a crap shoot on the CG and CB, both of which will be critical in a boat scooting along at speed. The sponsons are a sure fire tripping hazard and frankly the first turn at speed will dump the skipper in the drink, possibly with enough force to eliminate further experimentation. I've tripped boats, rolled them, capsized a few, had them swap ends because I drove over the CG and even pitch poled one. I lost a friend last summer when his race boat drove over it's CG (as a result of a wake) and he pitched, then was tossed out and run down. It happens on a fairly regular basis. Even highly refined designs can get "caught" with tragic consequences, just watch any powerboat race on TV and you'll see a few, that just got unlucky. Couple this with a design full of "issues" and the best advise would be, to make sure your insurance premiums are up to date.

This doesn't mean don't try, but it does mean don't try all the ideas all at once. First off, you will not learn anything, because you will not know what did what. Design a fairly conventional shape, maybe with a step, or a deep forefoot, then try it out. Play with the step location, depth of the forefoot and see if you've gained or lost. Skip the sponsons, you're just going to rip them off in a turn or trip the boat, neither of which is desirable. As you learn what works and what doesn't, you can expand the design with other ideas and contrivances.

I say go for it, but use a less daring under belly at first, so a reasonable level of success can be achieved, right out of the box. As you add and subtract stuff, you'll know which is doing what to the performance envelop. For what it's worth, you want a clean, unobstructed under belly, with the least amount of protuberances and drastic shape changes. You don't want anything in the water that doesn't absolutely have to be there. Anything that does live down there should be aligned with the flow and as diminutive as possible.

PAR, this is exactly what I am looking for. This type of response I really appreciate.

I like you're idea of starting off with a subtle step and "forefoot". Then if it's successful see if making it more aggressive has any positive gains.

My idea now is to find a proven mini hull that is similar is shape. My idea is to cut lines in said hull where I have drawn the red lines on the drawing below. Then remove the shaded red area to shorten that section by a few inches. Then using the green line as a pivot point for the lower hull I will rotate that section on the bow end in the direction that the blue teal(blue) arrow indicates.

That rotation angle could be varied at different degrees to test the effect of that shape.

I can see the top speed of this boat being in the 50-60mph range. I would be mainly focused on hole shot or acceleration. I am not sure how I will change the design of the sponsons but it seems there have been a few that are saying the same thing as you, that it will trip the boat when cornering. I will attempt to design them in a way they are adjustable. If adjustability is too difficult to design I'll use the design of wave runner sponsons as a guide so they are more likely to be effective.

Thanks for your focused and regardful response.