Keel, bulb and rudder design

[ivansalasj]

Hi,

I have been asked to carry out the preliminary design for a fast cruising sloop as part of my course in Naval Architecture. I am now designing the keel + bulb and rudder for the yacht hull i have designed. Some of the main dimensions of the hull are:

Displacement 81350.755 kg
Draft canoe 1.3 m
Lwl 25.555 m
Beam wl 6.116 m
WSA 149.571 m^2
Max cross sect area 6.361 m^2
Waterplane area 112.405 m^2

Can anybody suggest me what is the best approach towards designing the keel + bulb and rudder, i.e. areas, position, section (naca?), weight of the bulb, etc...

Thanks,
Ivan

[Doug Lord]

Get Larsson and Eliassons book: "Princibles of Yacht Design" . What kind of course material are you given?

[ivansalasj]

I have the book with me indeed, brilliant book. Course material? you mean requirements? I would like a bit more advice in such things as the weight of the bulb and the area of the keel,i.e. what percentage of the sail area do people think is better to have as the keel area, and how much percentage of the overall weight should i allow the bulb to carry (45% maybe).

Same with the rudder.

Also i am now working on the midships structural arrangements and if anybody can suggest a good route to take to ensure good results i will be pleased to know. I am thinking of following the ABS offshore racing rules but not to sure yet.

Thanks

[water addict]

I have the book with me indeed, brilliant book. Course material? you mean requirements? I would like a bit more advice in such things as the weight of the bulb and the area of the keel,i.e. what percentage of the sail area do people think is better to have as the keel area, and how much percentage of the overall weight should i allow the bulb to carry (45% maybe).

Same with the rudder.

Also i am now working on the midships structural arrangements and if anybody can suggest a good route to take to ensure good results i will be pleased to know. I am thinking of following the ABS offshore racing rules but not to sure yet.

Thanks

Weight keel weight and area are discussed in the book, as is rudder area.

ABS is pretty good, it's also distilled into concise form in Larsson & Eliasson.

[Ssor]

Ivan, Why not round off the displacement to Kgs. without the decimal point? If a bird comes by and leaves you a gift it will change your figures.

[ivansalasj]

Just the answeras from the hydrostatics, quite a big gift the bird has to give me!