What Makes a GREAT hull????

[Mikey P.]

Mich, no rip-offs. Our friends from Asia have that market cornered. Can one talented individual come up with a new concept??
Dougiie

If this boat performs the way I hope it will, I expect a knock off. At that point I'll just lay some with glass instead of carbon and under-cut the competition!

I'm still looking for a CNC machinist to help us! We might have a friend who can help. If I can't call in a favor this project might go to the wayside. Paying a professional to do a mock up on cad then paying a machinist might prove too expensive for our budget.
I can hand shape a boat, but it has no chance of coming out symetrical.

[ace028]

can't you autocad a hull, then lazer cut the frames, so they are perfect, then skin it all done on a jig? It would be near perfect if you take your time and make sure everything is straight. I'm only suggesting that for if you can't get ahold of someone to cnc the stuff for you. There seems to be a lot of interest in this, so I would hate to see it not get done, the old fashioned way could be a start.

On another note, are you going to make a few prototypes for some people to race to get pros and cons of the design in racing conditions before you start cranking them out? It would probably be good to get a few opinions on the boat so that any nessacary changes can be made before a production run.

[Ub Hauled]

This is a true rail (last picture) it's used not only with gas powered motors but also in BIG electric motor setups.
All we have to do is figure out how wide apart we want them to be... I guess another option is
mark a spot for a particular motor mount... I like the one they sell at Vac-U-pickle a lot... it
takes many types of motors and it has a support for the back of the motor... the only draw back is the angle
it is sitting at... maybe we can find a solution.

[Ub Hauled]

I agree with ace.. before you spend a lot of time in this and then have a ready boat, a prototype should be used to make sure the poor Cat handles like it should, if the sponsons respond well under higher speeds, if the motor mount is the appropriate style, etc.
Making a proto all in wood wood be a cheap and relatively easy way to do that. I could probably convert an Illustrator file or a PDF into the DXF/DWG format once you have something done. I also have a laser cutting guy if nobody can help in that department.

[Mikey P.]

Got it.

Quick question though. I know most of the cats have their sponsons turned in at the front 1/3 of the boat. I know that creates lift and stabilizes the boat. It also keeps the water under the keel clean. Do you guys think this is necessary or are parallel sponsons the way to go?

[Mikey P.]

Here is the "very rough" rough draft.

[Mikey P.]

What do you guys think about me buying this boat, improving it a bit, and making it out of carbon?

http://cgi.ebay.com/32-fibreglass-ca...d=p3286.c0.m14

I was thinking larger hatch, widening it a little, sharpening the edges, and shaving the sponsons a bit. please lmk

[Ub Hauled]

Mikey, i don't wanna rain on your parade, but you can get in serious trouble if you
copy the boat. You'd have to change it substantially in order to avoid a potential lawsuit and
then i wold not be that hull anymore would it?
If I was in your shoes, I'd avoid even trying to change it... you have to ask yourself the cost/benefit
of changing a hull even if it already is a copy of the Jolly (by Toysport)...
just my 2 cents.

[ace028]

I think your already on the right track by designing your own boat. Maybe changing the design for your own personal use, but not for selling them. I think that we need a completely new design, I have not had expirence with any hulls because I have make mine all from plans and such. I'm not a racer or anything, but my idea for a cool catamaran would utilize low COG, sleek design, not crazy with wings or anything, but a simple yet effective design.

How about vintage looks with modern design? I'm just throwing ideas around.

[Mikey P.]

I know you guys are right.
To hire a cad designer will run me like $1500 for 10 hours of design. I downloaded autocad and google's Sketchup. I can make the google program work a little but it may not work with a cnc. So I'm not gonna waste my time using it. The wood build idea is good if you can build a boat out of wood, which I can't. I know almost every characteristic I want to incorporate into the hull design. I just can't put it into a format that's useable. I did PM Jay "Fluid" with the proposition of using one of his custom hulls to make the mold from. Giving him the first hull for testing, and a small amount of money for each hull we sell, for his efforts. I have not heard back from him yet.
I'm not giving up! What's the record speed of a 32" electric anyway? lol

Here's a question to ponder.

This is the hardest question in hydrodynamics.

What makes a flag have waves?

[ace028]

I think there are several cad designers on this forum. You may talk to them about it. If you can come up with a 2d design, the guys at lazer works can cut it out for you in whatever size wood you need, then its like putting together a puzzle, if you make it right the peices fit together, then just glue it and skin it.

Really, you might want to make a few wood ones first, send them out to guys to test and get some feed back on changes that need to be made, then once you get the kinks worked out, then spend the money for the finial production run. I think if you were to document the build and success and input from racers, then there would maybe be enoungh interest to continue to the finial production, and it maybe worth the cost in the end. I'm sure that some of the cad guys on here aren't going to charge $1500, but I could be wrong. If you can get it drawn up cheap then send it to a cnc, I know that would be way easier.

I know that I would be interested in a finial production run considering the prices are very affordable.

[ace028]

Here's a question to ponder.

This is the hardest question in hydrodynamics.

What makes a flag have waves?

I'm guessing it has something to due with the high and low pressure of the wind passing around it and the fabric does not have enough strength to withstand the pressure from either side, so you get varying changes in pressure, so therefore you get waves. I am just speculating.

[Darin Jordan]

Here's a question to ponder.

This is the hardest question in hydrodynamics.

What makes a flag have waves?

Aeroelasticity, or maybe more precisely Dynamic Aeroelasticity... http://en.wikipedia.org/wiki/Aeroelasticity#Flutter

Same thing that caused Galloping Gertie to drop into the water... http://en.wikipedia.org/wiki/Tacoma_Narrows_Bridge

[egneg]

Aeroelasticity, or maybe more precisely Dynamic Aeroelasticity... http://en.wikipedia.org/wiki/Aeroelasticity#Flutter

Same thing that caused Galloping Gertie to drop into the water... http://en.wikipedia.org/wiki/Tacoma_Narrows_Bridge

Several years ago I was involved in building a suspension bridge model that had several different foil shapes that could be attached for wind tunnel testing for the reasons stated above. I have no idea how the testing went but I have never seen one built.

[Mikey P.]

lol. Was the bridge underwater? lol

ahem. I said Hydrodynamics not aerodynamics.

gotcha guys.

Well, I've got a pretty respectable sponson mostly drawn up on autocad in 3d. I am having problems making the angled edges. The program keeps snapping a line on the wrong axis. I don't have the manual because I'm using the free trial. I can see why guys go to school for this program. It has limitless tools and functions. I'll post my progress tomorrow