140' expedition Hull

[Hotel Lima]

I need help designing a 140' expedition yacht hull, we know how we want the design to work out but I need help in calculating boyency/CG/Drag and the power needed to push it.

Here's the rough spec's wanted;

Expedition style and ICE capable (big bow)

140' foot length

28ft beam

8knt long range cruise and somwhere in the 12 or 14knt range max speed
I want good range/gas mileage over speed. A sprint speed has be discussed but were not sure yet. We've also considered bumping the beam up to 30' or 32' but again we're not sure.

we like M/Y jasmin seen here and would like somthing simular.


Thanks;

Jake

[Hotel Lima]

I've been working in freeship and here's what I got;



is there anyway to get a cutting list out of this program?

[Hotel Lima]

I changed it up alittlebit, it's now 2ft longer to an exact 140ft and 35.033ft beam, waterline was brought up to 16ft flat, about 1.5 deaper than the origional.

[Hotel Lima]

I just found out that the displacement is 1479.2tons, isn't that like,.... alot for a boat this size........

I might need some help with this.

[Hotel Lima]

no one?

[Crag Cay]

Your design is like a model of a large cargo carrying ship. Its midsection is very full, hence the displacement. I doubt this would be the first choice for a vessel of only 140ft of the type you decribe.

Evolving a hull for such a vessel is not easy. There are lots of trade offs, but at the moment you seem to have prioritised carrying capacity over everything else.

When you start a design, find as many examples of similar vessels as you can that you know work in practice. Take their dimensions and reduce them to 'dimensionless' ratios that you can then use to compare one to another. For instance; Length/Beam, Displacement length, Displacement/Horsepower, Speed/Length Ratio for cruise and top speed, etc (Any book that explains boat design will give you everything about these: Brewer or Gerr's books, etc).

You can then work out far more parameters for your required design, including a stab at it's midship coefficient and prismatic for the speed and displacement you want. Your study of similar vessels may give you a hint about the shape of the midsection for the type of sea keeping qualities you think it will need.

Then you can do your first stab at creating the shape you want in your lines program. You use the computer to generate the vision you already have for the hull, rather than just let it dictate the shape.

My hunch is you are at least 500 tons (or way more) too heavy (50+ percent over weight).

What is the performance of a bulbous bow like in ice with a vessel of this length? Is 16 feet of draft going to work for you? Will you have any active roll stabalization? Where will the fins go? .....

A vessel of 140ft is truely a little ship. It certainly sounds like a courageous project as a first design. Good Luck!

[marshmat]

Jake,
I presume this is simply an exercise in tossing ideas around?
If so, then go nuts. Read up on the common dimensionless ratios, figure out what's normal in boats like this. Look at them when they're hauled out, see how things are shaped, see if you can understand why. Read. Surf the net. Have fun with it.

[Hotel Lima]

For the most part I'm messing around, Once I get alittle better I plan on designing a yacht for retirement, as I have a friend who owns a boat yard in Vietnam, who I Ironically met in Vietnam towards the end of the war and he is going to give me a good deal.

So I think I'm going to cap this one as I have lost intrest and I've learned my lesson.

I appriciated your input.

Jake,

[buckknekkid]

what are you scribbling in Forest City there? I may have a small project for you if you are good at rendering. Buckk

[Hotel Lima]

I don't get your question?