Need help for a 75cm model boat.

[Eristoff]

Hello, I am a French student at the Southampton 'solent' University in 1st year of Yacht and Powercraft Design and I need help to do my construction plan.

The rules for this monohull yacht are:

(L+(SA)^(1/2))/2=70

With L=(LOA+2*LWL)/3
LOA is the extrem length of the hull in cm
LWL (in cm)

SA= Sail Area= (I*J)/2 or (P*E)/2
I=Height of the foretriangle (cm)
J=Foretriangle base (cm)
P=Mainsail luff (cm)
E=Mainsail foot (cm)

The volume of displacement shall not be less than L^3/200 (cm^3)
The maximum draft shall be 35cm
The maximum length shall be 1.3m
Prismatic coeficient (CP) 0.54<CP>0.57
LCB 53%<LCB<56%

I am using MaxSurf and AutoCAD, but I have a probleme with the shape of my hull which is very hideous.
I am aware that my hull must be very thin and my boat light as possible.

I am also looking for some tips about the materials I have to use, like Glass Fiber or Wood,

At the end of the year there is a race (upwind and downwind) opposing all the students and with friend of mine, we will lived in the same house next year so we decide to award the biggest room at the winner.
I want this room.

To send me some advices please email me to: tom_dob@hotmail.com

If I won the race I promise a send a bottle of good french wine at the person who help me.
Sorry I know that my english is not really good.

Edit: Sorry....

[bhnautika]

Eristoff far be it from me to point out the obvious, but aren’t you there to learn, designing boats that is. You must have leant something because by your own admission you know the difference between a good and bad boat, but it’s up to you to fix it. In some forum’s getting someone to design your boat would be looked on as cheating. I think you need to look at this differently, most members would be happy to give you advise on your design.

[Tim B]

Eristoff,

Please don't ever ask the people on this forum to do your work for you again, it is dispicable and gives Solent a bad name.

Could I suggest that you ask people in the upper years what they did and how they did it, they're usually quite happy to help.

Most Solent students are conciensious and hard working.

Tim B.

[Eristoff]

Thank you for your reply, but I am completely joking about the construction plan on MaxSurf, I work all the night to have a good shape without the help of anybody, so I am very happy with it. I have to finish some calculation and I will link it on the forum to have some advise. I am so sorry for my request,it looks bad but it was not my intention. It could be good if some one give me some tips about materials to use....

[Raggi_Thor]

For the least work, design your boat as you like it, then slice it and cut the bulkheads on a laser. For lightest weight, build the prototype this way, then make a mould and vacuum bag some carbon fibre in epoxy with spheretex as a core.

[bhnautika]

Eristoff you should go and talk to the radio control boat classes, these guy can be of great help both in design and construction

[antonfourie]

On the sunject of models, how accurate is the test data from a model compared to the real thing as far as handeling / seakeeping goes. For example a 1/10 model of a 8m planing hull

[bhnautika]

Antonfourie RC models tend be ok in manoeuvring but poor in sea keeping prediction the physics are all wrong

[antonfourie]

Any reccomendations of how to accurately relate model to real thing ?

[bhnautika]

Antonfourie you need to make the model as big as you can, you can’t scale the water, also distribute small weights around the model for a more realistic weight distribution so inertia’s start to act more like the real thing. Just remember this is maybes.