Boat cross section determination

Be prepared for a hefty fuel bill.

 

Nobody can run a boat at full throttle all the time. I was looking into Hamilton Style jet drives also. I am guessing that the turbulence being encountered while taking water from below the hull is better than trying to push water that has come off the boat hull. Efficiency wise, the jet drive would be better right?

 

Well, going at sedate speeds is not the raison d'etre of Cigarette type boats. If you are fuel-conscious and happy to poke along at 20 knots, you may need a different hull design.

 

It may be worth considering a catamaran that can be disassembled into 3 parts (2 hulls + deck)

 

But wouldn't I get more usable area in a single hull boat? I have always sailed enterprise, laser and the like, single hulls. Never had the good fortune of being on a Catamaran.

 

usable area in a catamaran uses to be bigger than in a monohull. But note that the coefficient L / B = 12 is not very favorable or suitable for passenger comfort.

 

Are you trying to say that the boat when assembled could have a wider beam than 2 m? It makes sense but with an engine, jet drive and fuel system etc assembled and fixed in each hull, assembly would need real skill and effort

 

A Cigarette style jetboat ? Are there good alternatives to Hamilton drives? How would this drive layout affect the hull design?

 

Of course max breadth could be, for example, 6 m.
Anyway, speaking of a type of boat or other, without knowing the SOR of your boat does not make much sense.

 

I don't believe it would be. Here's a chart showing general efficiency of different drives...



http://www.boatdesign.net/forums/jet-drives/jet-vs-prop-efficiency-19655.html

The 'search' function here can help you. You can either search the whole 'Boat Design' site from the main page or search specific sections that you are in, such as 'materials' or 'powerboats' or 'propulsion' or 'boat design' etc. Also, if you scroll down to the bottom of the page of a thread you are looking at, such as this thread that you started, there is a section that suggests 'Similar Threads'. Doing that can keep you occupied until the camels come home or you receive any books you might order. Here's a link to this sites bookstore.... http://books.boatdesign.net/

Your English is very good, is it your native language? 'Awesome' and 'gun it' sound like Western terms, but I could easily be wrong. I suppose Bollywood must be pretty cosmopolitan.

 

Haha

I have nothing to do with Bollywood and don't watch any of the movies. My father is in the Indian Navy and have had the benefit of living the life of a Navy Brat.
Principles of Yacht Design by Lars Larsson and Rolf Eliasson is the book that I should be reading is what I have been told.
Maybe I should be looking at a Transcavitating propeller. The SOR or design intent could summed up as follows:
'A boat that can carry 5-6 passengers at 35-40kn at is within 12m overall length and 2m beam'
Thank you all for the inputs.

 

sudeb.roy, I guess you understand that with such terse SOR no one would dare to design the boat. Probably you not want to give more details due to confidentiality, intellectual property, or who knows why, but to get any meaningful help, you should explain something else.

 

Mate, don't get me wrong. There is no confidentiality being broken at all. If I am not able to get my requirement across, then it purely means that I don't have knowledge enough to elaborate further.
I am a complete NOOB.
Could you give me an example of what a SOR looks like. I'll look it over and adapt it for myself.

 

With all due respect, really, the issue is very simple, it's not about being a noob or not. It is thinking. For example :
- The boat will sail a small lake or with 3 meters waves.
- Outboard engine, water jet, ...
- What should be the maximum load.
- Should reach 40 knots at full load or ballast.
- Materials to build it.
- Autonomy at cruising speed.
- Number, type and position of the tanks.
- International regulations must comply
- It is a pleasure boat or a work boat.
- Maximum height, limiting depth.
- Deck with camber and/or sheer. No deck?
- GA plan
- any special equipment (diving, rescue, ambulance,...)
- etc etc.,
What would you like to do with your boat ?, besides putting it in a container.

 

Alright, I will fill out the points that I can understand.
1] Should be able to withstand harsh ocean conditions.
2] Inboard motor with transcavitating propeller
3] A maximum load of 4 tons
4] Aluminum
5] A cruising speed of 25 kn
6] 2 tanks and both located longitudinally along length of boat, preferably close to the keel point
7] Yes, must comply with all international rules.
8] It should be a pleasure boat.
9] The maximum height and depth combined should not exceed 2.1 m
10] Camber would mean angled or convex deck but I guess sheer deck. So, a sheer deck.
11] I don't have a GA plan as that is what I set out to determine when I asked about cross sections.
12] No special equipment.