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Offshore cat/tunnel design

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Old 09-16-2003, 10:34 AM
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Default Offshore cat/tunnel design

I am interested in someday building boats. Currently I am at Texas A&M Galveston in the marine engineering program. We mostly design offshore structures, and ships. I am more interested in fast powerboats. I think the degree I am getting is definately something that can pay for my hobby. Anyways, next summer I am going to get a nice facility and the propper tools to start building a boat. It won't cost much because a lot of things will be through the schools outreach programs, and most of the glass will be donated to the school. We are only going to build a hull, actually 2 hulls, one for wind/hydrodynamic testing. This will be a model, and then another to actual size. I have convinced them on 33 feet, because I want the boat. The hull pattens and any design accomplishments will belong to me and not the school, because I am donating the facility to build the boat.


Anyone on here who knows anything about tunnel hulls, it would be greatly appreciated if you were to give me some critique on my hull designs. I say my hull designs because I am the only student that has put a whole lot of effort into this so far.

The hull will eventually be designed in Pro-E then the model will be cut on our CNC machine. The actual big hull will have to be done elsewhere, or a plug be built. Any suggestions will be appreciated. Does anyone with a CNC that will cut a 33' boat have a website??
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Old 09-16-2003, 10:34 AM
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here is a bow view
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Old 09-16-2003, 10:58 AM
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The boat does not look like it's deep enough ... are you sure that the engines will fit where you want them underneath the deck? Also, are you sure there's enough room on the stern for the outdrives?

The steps look like they may be a little too big. You need to remember with steps that while they provide a hydrodymaic beneift (they should help you get on plane faster), they are structurally probelmatic, so the smaller you can make them the better from a structural point of view. Also, the first step is so far forward it may not even help you at all if you for an inboard powered boat (an outboard powered boat won't be quite as heavy in the ass obviously).

What type of hydrodynamic model testing are you planning on doing? What kind of wind testing (which is probably only useful for the deck)?
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Old 09-16-2003, 12:16 PM
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Ambitious,

Some suggestions:
Talk to the people at :
Nor-Tech in Cape Coral, Fl they build a 36 cat that you should look at.

Randy Scism at MTI

T2X- OSO member- this guy has forgetten more than most of us will ever know.

I agree w/ Beckles, you need a deeper tunnel to provide lift and that means compressing air. It shoud be 5 feet wide and rember to allow for the hull portion in the water.

Find a skater in the same size and look at the dimensions also.

Good Luck

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Old 09-16-2003, 01:58 PM
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I don't want to copy something I want an origional. I hope this CAD rendering comes out looking ok. The power fits. What do you guys think?
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Old 09-16-2003, 07:14 PM
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T2X??? Where are you?
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Old 09-16-2003, 07:46 PM
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Quote:
Originally posted by TopSpin80
I hope this CAD rendering comes out looking ok. The power fits.
Have you sized the stiffeners yet? I would suggest using the American Bureau of Shipping's Rules for High Speed Craft, it's good practical experience for when you go out and try and get a job. Similar rules are published by some other classification societies including Det Norske Veritas, but they're all pretty similar.

Anyway, back on topic, once you put the stiffeners in, I think may have issues with clearance. You have to remember those motors are going to vibrate and you're not going to want them to touch the hull (except of course at the mounting points) when they vibrate, and the clearances you show look pretty tight without any stiffeners.
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Old 09-16-2003, 09:39 PM
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Ask T2X about the Chris Cat boats.He is definitely "in the know about cats"
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Old 09-16-2003, 10:15 PM
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I agree, if you ask T2x and or GLH here on OSO, you will have a wealth of information and knowledge to work from/with. These guys are wonderful people and I am sure if you ask nicely, they will help you tremendously. I thought the same thing as Beckles regarding the steps being large and forward. I also agree with you that you do not want to copy another design. Best wishes for much success.
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Old 09-17-2003, 07:35 AM
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Quote:
Originally posted by Shane
I agree, if you ask T2x and or GLH here on OSO, you will have a wealth of information and knowledge to work from/with.
Me????? What the F do I know about anything??? You hitting the Pepsi hard again shane?

All I know about boat building is to make a small fortune you have to start with a big fortune in that business, sorta like racing.
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