Require some idea about CATAMARAN

Hello to everyone.

Recently i am trying to draw a good lines plan for a passenger catamaran.

LOA=36 m
B=12.2 m
D=3.0 m
Passenger number = 350
Total Displacement required =300 tonne
Speed = 12 knot

I am trying to make lines in a way where each hull will have 150 tonne on its draught mark(say 2 m).

I am also trying to keep its LCB position to LCG position and its LCB position is 2% forward from mid ship.

Now can any one please suggest me about my design procedure?is it ok or wrong? if wrong then please show me the path.What else thing i should do?
CAn anyone give some body plan of catamaran?

Shahriar
If wrong then what should i do?

 

The path is to go to school, either engineering or naval architecture. The other path is to hire a professional.

 

Thank you

Dear Gonzo,

Thank your for your reply. Actually i am a naval architect. I am trying to be a effective naval architect.I did not designed any catamaran.
Again thank you for your reply.
Can you give me some basic knowledge about designing a catamaran?

Shahriar

 

Why does it have to be 300 tonnes ?

 

With 350 passengers,I guess they're quite large.

 

Dear Efficiency,
Thank you for your reply.
Actually its weight will be steel weight 155 tonne+passenger 27 tonne+fittings etc 50 tonne+ cargo 35 tonne + 10% provision =293.7 tonne (Rough calculation). I have taken too many safety factor as there may be more passenger on ship on festivals.
Hoping to get response or any kind of suggestion.
Shahriar

 

You might mention its intended area of usage, river, bay, open sea ? There are quite a few professional designers here, I'm not one of them, but my two cents worth is why a catamaran when a barge of that size would get the 12 knots you specify, and presumably with less draft and cheaper to build ?

 

As a naval architect you should already have all the basic knowledge; advanced too. How do you find it different to find LCB, LCG, etc. from a monohull? There are some specific design characteristics to catamarans. For example, deck height over the water and wave interference between hulls. However, it doesn't affect what you are asking for. Stability calculations are similar in that you have to find the righting arm. On a motor catamaran, it won't be flying a hull, so the operation will be quite conservative.

 

There is a book 'Multihull Ships' written by Dubrovsky.

Then, I have published number of papers on catamaran design:
1. Nazarov A. Application of catamaran concept for small commercial, special and pleasure craft// 16th High Speed Marine Vessels Conference (HPMV-2011) - Shanghai, China, 2011. – E18.
2. Nazarov A. Comfort on boats and yachts: design factors //Australian Power Multihull Vol.17. – May 2011.
3. Nazarov A. Power catamarans: design for performance// 2nd Chesapeake Power Boat Symposium - Annapolis, USA, 2010.
4. Назаров А.Г. Особенности проектирования малых катамаранов прогулочного, коммерческого и специального назначения// «Судостроение» №4-2011 (797), с.12-17. (Nazarov A. Design of pleasure, commercial and special small catamarans; ‘Shipbuilding’ #4-2011 – in Russian).

 

yikes

 

Dear efficiency,
Thank you for your mail.
Yes you are right. Its area of usage is river but the main problem is that the size and type of ship is fixed by the owner. Here there will be 300 people on board with sitting arrangement and there will be cabins for 50 people on poop deck.
Thank you for your mail again.

 

Seems to me that the current trend towards catamaran ferries is largely a product of the need for greater speed than is obtainable in displacement monohulls, there being no other realistic way to achieve it in a 36 metre 300-ton vessel. If 12 knots is all you want, a barge will give you that.

 

http://www.afloat.com.au/afloat-magazine/2009/september-2009/Tangalooma

This vessel is about 55 metres, a catamaran passenger and vehicle ferry cruising about 20 knots I think, replaced barges doing about half that or a little better.

 

Dear Mr. Stephen I.M,
Thank you for your reply. Hoping to get more help from you.
Md. Shahriar Nizam

 

Construction for such design is from epoxy-stitched glass-foam cored composites for both shells and internals.