What I should do?

[Abby Chan]

Hi all,
I am now designing a boat for 15 passengers including the boatman.
I firstly decided that my boat length is 20m, beam is 6m, draft is 1.2m and the speed is about 10 knots.
I know that I need to find the power required of the boat or I can say that I haven't any idea that where I should do first. Do anybody can help me (give me some guideline)or could someone give me some suggestion what I can do first?
Best wishes,
Abby

[gonzo]

Are you serious?

[Abby Chan]

Dear Gonzo,
Yes, I am serious. Actually I have no experience on that, do you think there is something wrong on the parameters on my boat? or you have any comments on that? I know that there should be many mistakes on the assumptions on my boat, so please give some recommendation, thank you very much! I need your help indeed!
Best wishes,
Abby

[D'ARTOIS]

Mr Chan, the reason for Gonzo's sceptical reply on your request is that quite often in this forum we are faced with invitations of 3 or 4 lines asking for advise for a project that needs a serious approach.
The way you put your question forward does not invite for a serious look at your request.

First of all, start to explain, not only what you require, but also where it is used, in what kind of water or sea, going where, payload etc.
We cannot advise you if your parameters are good or wrong, we have no references of what you plan to do with your intended vessel.
In your case I may advise you to check with a local shipyard. They know more than you do and they speak your language, knowing the means of available funds and further requirements.

[CDBarry]

The one thing I notice most often on this forum is exactly expressed by this query.

The two most critical steps of boat design are definition of requirements and constraints, and optimization of basic parameters to meet these requirements and constraints. (I lump requirments and constrainst togther to avoid having to decide if something is a requirement or a constraint. You might also add determiniation of "desirements" at this point as well.)

It is critical to approach this with an organized process or you won't get what you ultimately need or to make design decisions. - To quote the Cheshire Cat - "If you don't know where you are going it doesn't matter which direction you go."

Start by writing a "Owner's Requirement Document". Based on this, write a "Circular of Requirments" that fleshes this out. Then you can start looking at optimizing parameters by using cost vs size models, cost vs speed models and so on. (If you have access to a program like ASSET, this is considerably easier). This may (probably will) cause you to revisit your ORD. Then when you have the required parameters you can then start thinking about this sort of design question. Start by doing a "point design" to see if your parameters work together at all. You may want to do several using different combinations of feasible parameters. Then plot out cost vs the different factors and pick a final optimum and design that.

Thank you very much! and I will try to check with my local shipyard

[Abby Chan]

D'ARTOIS, Thank you very much! and I will try to check with my local shipyard

[Abby Chan]

CDBarry, Happy to see your advice and the suggestion, Thank you very much!

[lakerunner]

Once you get going and achieve a good workable plan. don't be afraid to use this site ..
You will get plenty of answers and help . But as you may already understand early on, you need to research your project and make your questions clear, There are many variable to certain designs. Are you building a Ferry....riverboat...Pontoon...cat...mono hull ...15 passengers is a pretty good size boat. You see what I'm getting at.
Do your homework and surf the net for Ideas . There are many boat yards in hong kong that should keep you busy for many weekends. . But again .. do your Homework
and ask clear questions and you will find the help you look for here....Good Luck Mr. Chan.....

[lakerunner]

Just from what you show ..... Your draft is shallow for that size of boat.I can only think of a barge style ferry.
Again ...just can't tell... do you have a thumbnail ( sketch ) of your boat?
Send one Lets take a look......... djvcwg@yahoo.com

[Abby Chan]

Lakerunner, you are all nice guys here, so I won't hesitate to learn from this site. I would do more homework first. Thank you so much!

[gonzo]

Probably the most important item is the available budget. It will determine everything else. For example, where to compromise between durability and price.

[PAR]

Always the correct starting point Gonzo . . .