Wanna build a bigger welded Alum. craft

[kanuckle head]

I started with Autocad using drawings to scale

For example drawing a 4x8 sheet with 4 squares by 8 squares & so on

Now with my scaled drawings I'd print a whole S**T load of um

On my spare time I'd cut & tape to my hearts content

The best look'in would pass the drawing board

& this is what I came up with
3 1/2 sheets of 4x8
One sheet for the bottom& one sheet for the sides
The rest for transom & seats
It became a 12'3" x 5' 4" craft that rivals my Grady to scale due the fact of how she displaces water & easily goes up to plane

Now my ?? is I have collected a 5x12 sheet of 3/16 thick for the bottom & a 5x20 1/8 thick for the sides, will this design work on a larger scale but wit higher sides for the CHUCK

The motor extension is now boxed in & filled with spray foam, also the seats
Prior to the motor extension being boxed in the craft would dig in the transom end & not go to plane no manner the max tilt on the motor

Thanx for reading this post, your feed back is greatly appreciated

[kanuckle head]

Found a sweet design I drooled over, in my eyes a piece of art work
With those large reverse chimes I can tell she aint a wet boat & with it's sharp angle bow....like slice'n soft butter

The one flaw with this design has a lot of crop as wasted material
But what a BEAUTY !!!!!

[Guest62110524]

it does have a nice entry, but the waterline beam is narrow. the semi monohydron, may keep her from being tippy and tender and help her lift if the chines are wide aft, the strakes are not at all necessary especially the upper one, all it,ll do is make her harder than she should be

Looks like some weld penetration from the sole?
But yes more boats need this type of entry especially at sea

[kanuckle head]

Originally Posted by whoosh

it does have a nice entry, but the waterline beam is narrow. the semi monohydron, may keep her from being tippy and tender and help her lift if the chines are wide aft, the strakes are not at all necessary especially the upper one, all it,ll do is make her harder than she should be

Looks like some weld penetration from the sole?
But yes more boats need this type of entry especially at sea

Dude that's some funky lingo U B spu'n
But very curious 2 under stand how you got that consept

Please illiterate more in detail, cuz I'm not a boat builder by trade
But a builder by vision & mat'ls in availability
Basically I work with what I have @ hand

What's a monohydron........ or a strakes???

Thanx 4 your feed

[Guest62110524]

you make me smile
mono is when the chine runs parrallel with keel
those strakey things are those bits welded to the bottom plate, they usually are put there to make boats track better, but most are there for looks
narrow beam can be tricky down wind in bigger seas esp with deep vee as when the bow digs in, like a running situation( when the bow digs in it can lead to a broach, A broach is something you do not wear on your blouse, but is something that tips the boat onto her side, all very well on a yacht(sometimes) but in a power boat can lead to a total capsize When this happens it is not fun

[kanuckle head]

Originally Posted by whoosh

you make me smile
mono is when the chine runs parrallel with keel
those strakey things are those bits welded to the bottom plate, they usually are put there to make boats track better, but most are there for looks
narrow beam can be tricky down wind in bigger seas esp with deep vee as when the bow digs in, like a running situation( when the bow digs into a wave when running faster than the wave) it can lead to a broach, A broach is something you do not wear on your blouse, but is something that tips the boat onto her side, all very well on a yacht(sometimes) but in a power boat can lead to a total capsize When this happens it is not fun

Tanx 4 tat input
2 prevent a broach will a wider beam help or a larger chime ...even a reverse chime
In the same retrospect of a rigid hull inflatable...cuz I can't see a inflatable being tippy

Mind ya It's weight 2 to displacement ratio .........correct!!

[Guest62110524]

the chine is fine, only bells (chime)
yes wider beam
Now I must partake of the stuff made from hops

[kanuckle head]

Originally Posted by whoosh

the chine is fine, only bells (chime)
yes wider beam
Now I must partake of the stuff made from hops

ya me 3
only the king of BEERS 4 me
cheers

but I am a sponge 4 knowledge & need more input
because it's always better 2 measure twice & cut once

[Guest62110524]

Originally Posted by kanuckle head

ya me 3
only the king of BEERS 4 me
cheers

but I am a sponge 4 knowledge & need more input
because it's always better 2 measure twice & cut once

you are dead right, there are many different approaches, but no shortcuts in boatbuilding , Bon Chance

[Bigfoot1]

ouch! to whoosh who does not understand lift strakes
lift strakes when properly designed generate just that---lift

If you take a mass, the moving water, and accelerate it, you get a corresponding reactive force.

Acceleration is a change of velocity ( dont mix speed and velocity, they are not the same thing)

and governed by the equation by F ( force) equals mass times acceleration

(to the engineers, I am meaning mass flow rate "m dot" for sure in this example)

Velocity has two components, speed and direction

So water moving at 20 mph/kmh is moving with a speed of 20

But water moving at a speed of 20 units say north has a velocity of
20 speed units North

So if acceleration is a change in velocity, you can now change either of these two of these parameters, speed or direction to get a resulting force.
Or in this case lift.

So in a hull moving through the water, planing hull, the water is moving up and away from the keel of the boat. There is a component that is moving at 90 degrees to the keel and if you take this mass which has a velocity, say 20 degree deadrise, and therefore this vector is 20 miles per hour (the speed component of velocity) and it is moving at 20 degrees off the horizontal ( the direction component of velocity) , and you have a lift strake turn it to horizontal, you have then changed the velocity meaning that you have accelerated it and it produces a force, lift.

So in order to get a force, lift, we changed the velocity by changing the direction, which means we accelerated the water.

Note most lift strakes have quite a sharp transition corner, if you will, between the hull bottom and the strake bottom. So you get some impingement of the water on the strake, ie not a smooth curved flow. This hampers lift, ie creates a stagnation point and turbulent area inboard of the strake.

Is this true you might ask. Well it is because every turbine, incompressible (liquid) or compressible ( gas) works on this principal. Take a stream of air, water, it will enter the turbine blade smoothly and exit at a different angle, ( the speed remains the same, well mostly) smoothly, if possible, and the vane will see a resultant force on it.
This is simplified of course. Back of vane negative pressure, shadows, fixed straightening vanes, turbulence etc complicate the process.
But in this single vane, the lift strake, the engineering principals apply quite simply

[Bigfoot1]

but you have already paid the price, in fuel burn, to move the water out to the sides of the boat, and basically made a wave which is stored energy. So the strake is properly built will get Free Lift
Of course a flatter deadrise will do the same thing but flatter can mean a much harder ride all of the time.

The problem with most current strake design is that they do not have the exit direction turned down enough , ie turning the water through a greater angle of inlet to the strake and outlet from the strake so that you maximize lift. If the water is coming off the strake horizontal it would affect some of the lift that you could get immediately on the outside of the strake against the hull.

good discussion anyway