i would like to see a slide-in-out catamaran designed

So, what is the predicted performance then with and without?

 

Slower with, faster without, unless there is the use of miracle materials and techniques that increase neither weight nor windage !

 

You're avoiding again.

I'll ask the question again for the hard of reading.

1) What is the performance, its speed, without
2) What is the performance, its speed, with.

 

Silly question, what is "it" ? He asked a vaguely defined question, he got a vaguely defined answer. There may be less weight penalty than I imagined, maybe more, depending on what he wants, which at first blush seems like an extensive wish-list. But I can't see how structural integrity can be preserved, with identical weight, unless material substitution, probably expensive substitution, occurs.

 

Nope.

Since you're able to make such statements about the performance, please enlighten me what speed this boat is going to achieve, with and without such an extension.

Since "it" is the raison d'etre of the discussion.

 

I am quite comfortable with what I said, the boat will get heavier with the extensions and alterations, in all probability, and all else being equal ( like the demihull separation) it must then be slower, I can't see where that is extrapolating too far. But please explain otherwise, by all means.

 

I can read that. But you're missing the whole point.

Well, let's look at what you said:

So you have made a statement about the L/D ratio. So how does that square with the question of: can/has a boat been designed/made that is extendible?....please enlighten me. I'm all ears.

So in your attempt to sound like you're fully familiar with the L/D ratio you have no idea about the vessels:

speed
hull material
number of pax
motor or sail
size
displacement
range
endurance
cost

etc...etc..etc.....

yet without know diddly squat about the boat at hand (because none exists), you're comfortable making comments about a feature of hydrodynamics that has nothing to do with the question, nor, without knowing any of the features noted above (it is not an exhaustive list BTW), you're saying:

I'm amazed that you have such insights to the required design features of this unknown boat and what it is designed to do (other than be extendible) to say it will be heavy - implying it wont work-, when such a design has yet to be presented. In other words, its SOR. You must have amazing powers of ESP.

Adding weight to a fixed design is clearly going to make any design slower...but...er..how much..and er...what fixed design is it that you're referring to...as none exits!...and does it matter??...i.e the SOR

 

Haha, you are relapsing into your Captain Cranky Pants mode that pops-up from time to time, but I did not say it "won't work", I merely made the observation that a catamaran requires to be more weight conscious that some other types of vessel, but if that is wrong, a lot of people have been telling me porkies ! ("pork pies" (lies)).

 

Did adhoc wake up on the windward side of the bed again.

 

Indeed. But that's the obvious part. Does it matter...that's the real question. Since if it still satisfies the SOR...so what?

Hmmm..may be

 

Well, if you are going to lose the speed advantage of the catamaran in this process, why opt for the cat at all ? Just go for a boat that has the accomodation spaces you want, could even be a houseboat with an extra storey added !

 

There you go again. You can't help yourself!!

What speed advantage and how much??? Absolutes, not off the cuff generalisations.

 

*yawn* I think this argument has "progressed" to its maximum potential.

 

I'll let others decide who is flogging a dead horse here !