Boredom design

[JLIMA]

Just out of boredom I've been tinkering with freeship 2.9+at a little center console (21' or 6.4m for you metric types). Just figured I'd post it up see what you guys think of her and if any of you have any recommendations on any improvements to her. I know she's a low boat but thats just my preference I like the way they look. Might turn out as a build but right now it's just a mental exercise for me to occupy my time with.
Dimensions are:
loa 21'/6.4 meters
beam 6.6'/
draft 9"/
displacement of 1,600 lbs

Here are the sketches.

[hoytedow]

Nice lines. How do you plan to power her?

[JLIMA]

I would thing a 25 hp long shaft would work just fine for the displacement speeds I was thinking on, but like I said no plans to build her just yet..

[Asleep Helmsman]

I looks like the top sides are constant camber.

What software did you use and does it allow for continuously changing curves?

Pretty boat by the way.

[JLIMA]

For that I used the new FreeShip 2.9+ I think and as far as I know it allows continuous curves. Not sure yet that I like the control points though, I'm so much used to pencil.

[PAR]

That fore foot is going to "root around" and 25 HP is way more then you'll need for 7 MPH of hull speed you'll have in displacement mode. That shape isn't the best one for these speeds.

[JLIMA]

Par thank you for the incite, like I said it was just something I do to pass the time when I'm not working on someone else's boat. I was thinking 25hp just to have that extra power in case it is ever needed and a 10hp would still more that get her to hull speed. About the fore foot what would you recommend to minimize the "rooting around"?

[JLIMA]

Or do you think this would do the trick?

[nukisen]

If you want you could start a new thread and let everybody post their idéa of alternative power for the boat. It would might be interesting. Also you would be able to read a lot of idèas when boored.
Sorry! I did forget to tell that for me the design looks quite okey!

//Janne

[PAR]

More study on displacement hull forms, is my recommendation. I'm not trying to be coy, but there are several glaring issues in my opinion.

[frank smith]

Originally Posted by PAR

More study on displacement hull forms, is my recommendation. I'm not trying to be coy, but there are several glaring issues in my opinion.

I dont have much trouble with the bow or the transom , it s always the the part in the middle that stumps me .

Frank

[Asleep Helmsman]

Originally Posted by PAR

More study on displacement hull forms, is my recommendation. I'm not trying to be coy, but there are several glaring issues in my opinion.

What are they?

It looks like a planing hull to me.

[JLIMA]

Not a bad idea for the alternative power thread, and for Par if you don't mind pointing them out besides her looking like if you pushed her hard enough she'd hop up on plane? I'm kinda limited in the time and money and the local library doesn't have jack so failing books there's nothing like a good critique to learn something from inmo. After all i don't design boats for a living just weld on them.

[Ike]

If displacement speed is what you want then the aft surfaces look ok, but if you want itto plane you need a broader stern and flatter buttocks aft.

[TeddyDiver]

I think you should look into this thread center of flotation calculation and implications?
It's good to read throw, but believe one thing PAR meant is the fullness of hull (or the lack of it). Cp and the S/L ratio are the ones you should be most interested now. They are mostly in page 6 in that thread..
Otherwise it's nice looking concept..
Teddy