Beginning: Hull shape and size

[Jeremy Perkins]

I’m new to boat building and I’m trying to figure out how to build cataraman hulls 9 feet wide by 75 feet long and I don’t have any idea where to begin.

 

[Ad Hoc]

Hi Jeremy,

Welcome to the forum.
Unfortunately whilst it sounds easy, it is not so straight forward.

Since what is a hull, it is a 3D shape that supports the whole weight of the total boat, when in water, and floats on a given waterline.

So, to "design a hull" one needs to know what is going inside it, the weight, and then what speed you hope to achieve - defines the shape more than just a box.

So, without further information, it is not so easy to answer.

 

[bajansailor]

I’m new to boat building and I’m trying to figure out how to build cataraman hulls 9 feet wide by 75 feet long and I don’t have any idea where to begin.

Could you elaborate a bit more about your boat building plans please Jeremy?
Re your 75' x 9' cat hulls, are they your design?
If not, who designed them? Are you able to post any sketches or drawings of them?
Please do take careful note of Ad Hoc's comments above, especially re the weight calculations - excess weight during the build has been the downfall of many a catamaran builder.

 

[Alan Cattelliot]

I’m new to boat building and I’m trying to figure out how to build cataraman hulls 9 feet wide by 75 feet long and I don’t have any idea where to begin.

Scaaaaaaaary... I hope the moderator could help us a little bit here, and could also be indulgent with regards to the following :

Hi Jeremy,
I ask ChatGPT for you (my best new friend ). Here is the answer I had to your question :

Building a catamaran with hulls of such dimensions is a significant undertaking, especially if you're new to boat building. Here's a general overview of the process to help you get started:

1. Research and Planning:
   • Familiarize yourself with catamaran designs and construction techniques. There are many resources available online, including books, videos, and forums dedicated to boat building.
   • Consider the intended use of your catamaran (e.g., cruising, racing, fishing) as this will influence the design and construction process.
2. Design:
   • Decide on the specific dimensions, layout, and features of your catamaran. You've already specified the width and length of the hulls, but you'll also need to consider factors like draft (how deep the hulls will sit in the water), freeboard (height of the hull above the waterline), and overall weight distribution.
   • You may want to consult with a naval architect or experienced boat builder to ensure your design meets safety and performance standards.
3. Materials:
   • Determine the materials you'll use for construction. Common options include fiberglass, plywood, aluminum, and composites. Each material has its own advantages and challenges, so research carefully and choose based on your budget, skills, and desired outcome.
   • Consider sourcing materials from reputable suppliers to ensure quality and compatibility.
4. Construction:
   • Prepare your workspace. You'll need a large, well-ventilated area to build the hulls.
   • Start by building a strong, level platform to serve as the foundation for constructing the hulls. This platform will support the frames and provide a flat surface for assembly.
   • Construct the hulls using the chosen materials and techniques. This typically involves creating a framework of ribs and bulkheads, then covering them with hull plating or fiberglass.
   • Pay close attention to symmetry and alignment to ensure the hulls are balanced and consistent.
   • Assemble additional components such as the bridge deck (the platform connecting the two hulls), crossbeams, and any interior features.
5. Finishing and Fitting Out:
   • Once the basic structure is complete, you'll need to finish the hulls by sanding, smoothing, and applying coatings or paint for protection and aesthetics.
   • Install fittings, hardware, and systems such as rigging, engines, steering, electrical wiring, plumbing, and interior accommodations.
   • Test the catamaran in water to ensure it floats properly and performs as expected.
6. Safety and Compliance:
   • Make sure your catamaran complies with relevant safety regulations and standards, such as those set by the American Boat and Yacht Council (ABYC) or the International Maritime Organization (IMO).
   • Consider consulting with maritime authorities or professional inspectors to ensure your catamaran meets all necessary requirements.
7. Launch and Enjoy:
   • Once your catamaran is completed and certified, it's time to launch it into the water and enjoy the fruits of your labor!

And here is my answer : If you haven't found any youtube tutorial "How to build my 75' catamaran, please, go find a NA you are confident with. He/She will save you a LOT of time.

 

[bajansailor]

@Jeremy Perkins I hope that you are still with us?
The Forum has not seen any sign of you since Tuesday evening.

Please do tell us some more about your catamaran building project.

 

[jehardiman]

famous sailing-related quotes https://forums.sailinganarchy.com/threads/famous-sailing-related-quotes.37604/post-792688

 

[calevi]

I’m new to boat building and I’m trying to figure out how to build cataraman hulls 9 feet wide by 75 feet long and I don’t have any idea where to begin.

I would start by buying stock plans for cat similar size you're intent to built.

One example.
Bruce Roberts, steel boat plans, boat building, boatbuilding, steel boat kits, boat kits https://bruceroberts.com/public/HTML/CAT785-24M.htm

 

[BlueBell]

Jeremy, don't ghost us, come on, step up.

What speed do you want, from what propulsion, and what hull material?

 

[comfisherman]

Good old Ai, making a 100 word essay into a 500 word essay without actually saying a thing. At first I kinda chuckled at the ai response but have had some time to think about it. Kinda feel like these semi vague very unrealistic threads are ai bots attempting to learn how to illicit a response. Like some kinds of machine learning to test and see if ai can drive engagement.


Probably are folks who do one hit wonder posts about going from 0 to 75 foot cat.... but I'd like to believe it's just code trying to drive or test drive its ability to push engagement.

 

[BlueBell]

I’m new to boat building and I’m trying to figure out how to build cataraman hulls 9 feet wide by 75 feet long and I don’t have any idea where to begin.

So, Jeremy, you are lost.
And now you are non-responsive.
What a desperate situation you are in.

Hint: Start at the beginning. Good luck.

 

[Burger]

Build a plywood box 9X6X75 make one end pointy.

 

[BlueBell]

I would suggest you make both ends pointy.