Vee hull features.

[785boats]

It's true that raising the angle of the strut too much causes the hull to run very loose, & dropping the strut too much causes the hull to run too wet. Everything has a point of 'diminishing return'. It's a question of finding the right balance with the strut angle, the COG & the type of prop being used to get that slight nose up attitude of the hull in full flight. Again we are only talking about 1 degree or so.
Simon.
If you are using a flex drive, with either a strut setup or stinger type setup, I believe as low as you can get it is best for the exit.
As an example the centerline of the stinger on mine is 8mm above the bottom of the keel.

Paulwilliams.
I too have just been reading through your website. Great stuff. Going back there now for some more learnin'
Cheers.
Paul.

[crrcboatz]

The monos that have "hook"built into them are few. The designers had the experience to know what they are doing with the hook design in the first place. I would apply the KISS rule, aka, keep it simple ______. The 2 that come to mind do not use trim tabs and the hook is as someone earlier mentioned, near the transom.
Do yourself a favor and get that hook out of the boat you are building. Someone like you with the God given ability to build from scratch, I covet your skills, should not put themselves through the trial and error of what a hooked bottom can cause you in the way of heartache. Man I wish I had the skills to do what you are doing!!!!!

Curt

[Simon.O.]

O.k I now have enough info on strut height and angle.
Next is :
Prop distance from transom
I understand that 10 % of hull length is normal.
I can see the problems that may arise if it is less

What happens when it is out further ?
Faster ?
Less prone to blow over ?
Poor steering ?

What else ??

[ozzie-crawl]

the further out the prop the less tendency to porpoise but more chance of chine walk, i think this is were the 10% comes in as it is a compromise between the 2

[paulwilliams]

the further out the prop the less tendency to porpoise but more chance of chine walk, i think this is were the 10% comes in as it is a compromise between the 2

That says it all

There are no "hard and fast" rules, just a set of generalisations that can be used as a "first guess", unless, of course, you're building a proven design and have an explicit set of setup instructions from the designer regarding balance point, prop location, rudder mounting point etc.

As you're building your own design, then you will have a certain amount of tinkering to do in order to get the best from your boat - you are very unlikely to hit the exact setup first time.

Bear in mind that altering one thing to eliminate one problem can quite easily cause another. For example, the further out you place the prop from the hull's CofG, the more leverage it will have and the more prop walk you are likely to get. I say "likely" because it's unknown - you may, or may not, it's merely theoretical.

Another example is prop depth. It is usually the case that raising the prop reduces motor load, which is good, but it also usually increases prop torque effects, ie., prop walk and torque roll, which is bad.

Paul

[ozzie-crawl]

i actually started a thread acouple of days ago on this same thing but with cats as i havent been able to find an answer.
sorry simon not trying to jack your thread