Catamaran materials

Hi everyone.

I'm planning to design a 38'(12m)L and 15'(4.6m) B catamaran with 2 bedrooms and a living room with a kitchen included for spending leisure time this is why the sailing speed will be 10 knots. Using sails and also a diesel-electric engine seems to be the best propulsion method for this kind of ship.

Next step for me is to find the material for this catamaran with the best quality/price ratio and also the best material for not having too many borders in the designing phase.

What material do you think is the best for this type of boat??

Thank you.
Best wishes.

 

The "best" is a relative term.. Do you want the lightest, strongest hull, or do you want to find the lowest cost, or do you want durability and life, or do you want a material that is easy to build without molds????? Lots of ways to define best.. Depending on what you are looking for in properties, cost, strength, impact resistance, life.. If you're looking for a cruiser then you may want to give up some material strength for lower cost, heavier construction.. Bottom line is that there is no "best" for everybody, it's all a matter of compromise and that depends on your goals and desires. You can throw money away or you can cheap it out, just depends on your goals and desires.

 

Why diesel/electric?

 

First things first. Just forget the design phase. Buy plans for something you like and build it. You will have enough problems with that as it is. Diesel electric is inefficient in that size anyway, so forget it also.

To answer your question. You can choose between plwood, strip plank, foam or balsa cored fiberglass or carbon and single skin fiberglass. There is no "quality/price ratio" involved, every material has its goods and bads. Realisticly speaking you will have to decide if you use materials you can buy local or are prepared to import them from elsewhere in the EU.

 

What do you mean by "borders in the designing phase?"

 

Hi again.
I'm not thinking about building it myself it is for a school project were I have to design it from scratch. I wanted to hear more about other's opinions about which material fits best for such a boat. I am thinking about a hull light enough to fit everything it needs taking into consideration the dimensions but also to be strong and durable.
Diesel/electric because I thought about including a dieselgenerator when the batteries are no longer charged.
Thanks Rumars and others.

 

You don't choose the material, the technical requirements, or SOR chooses the material.
Since if the SOR says steel, and you design the boat and find it doesn't work because it is too heavy and wont float correctly..what do you do.....1) change the material or 2) change the design.
If 1) change to a lighter material, but may be too expensive now... if 2) ..ooppss...can't do, too big and expensive now.

Thus your SOR dictates which material is selected and how this fits into your design and budget to get the design compromise that is required.

 

Gonzo I think he means material imposed shape constraints, like deep V or multichine if using sheet material like plywood.

Bogdan I now see I forgot cold molding. Wich is basicly creating a custom piece of plywood in the shape of a hull out of veneers or thin plywood.
You can also combine different building methods and materials to achieve the desired shape and performance.
The building material also reflects the desired production volume to some extent. Production catamarans are usually infused in mold since this represents the best investment when it comes to high production numbers. Sheet construction on the other hand can be almost moldfree. So how and by whom and how many are going to be buildt are design criteria influencing material choice exactly like price and resale value.
I am basicly saying the same as Ad Hoc, what you want the boat to be dictates the material and building technique.

Diesel-electric means no batteries, like locomotives. What you mean is called hybrid propulsion. It only makes sense in very specific applications. Otherwise it's just a needless complication and aded weight. Generators are carried because of redundancy, insuficient generating capacity (outboards for example) or missmatched engine/generator/battery size/technology. They can be avoided by carefull planing if desired (wich may not always be the case since a generator can be the cheaper and/or lighter option).