Portofino
Well-Known Member
How’s a about this ?
AoA improvised meter .
- Thread starter Portofino
- Start date
BruceK
Well-Known Member
I've obviously struck a chord as intended. Perhaps you'll be a bit more circumspect in your own opinions about fellow forum members boats in future?
Here's flatass on legs doing the same in choppy waters. Not seeing anything particularly special here Porto
Here's flatass on legs doing the same in choppy waters. Not seeing anything particularly special here Porto
BruceK
Well-Known Member
Flatass cutting through chop. Loads of bouncing as you can see
Portofino
Well-Known Member
No “ cord struck “ or similar or whatever .
Just a nice simple easy AoA test , the water level .Wheres the “ meter “ in your vids btw ? You know getting round the camera angle etc - might be biased ?
Yep this whole outdrive / IPS dangly cathodic bits , with gears changing direction multiple times , only separated from the water by a perishable rubber ring is an engineering enigma.
Builders installing IPS having to kill the deadrise to enable a better joystick turn , without the lurching / heeling another airbrush able dilemma for the salesman.
Its all about informed choice.
The more folks turn towards the engineering side and hull form side nuances the better boating experiences they will have , if they want to be in the hobby longterm .That inc where poss keeping an eye on EGTs , load , water pump inlet pressure .
MapisM
Well-Known Member
I can't understand exactly from the video, what's the trick that you use to keep the fenders in that position?
I guess you don't untie/re-tie them every time, or do you?
jrudge
Well-Known Member
Business as usual. Itamas are the only boat wbuying and a sprinkling of EGT.
It does get boring
It does get boring
MapisM
Well-Known Member
I don't see one in yours either, actually. If you just download one of the many apps available FoC, you can monitor your AoA in real time (as well as the reaction to trim tabs), down to a tenth of degree accuracy.
Not that I'm so maniac to do such check regularly, but I did and got some interesting results upon seatrial of my boat, and now I keep that in mind for fine tuning while cruising.
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markc
Well-Known Member
Maybe you could get the developers to adapt this app to create an Itama version?
1000 Powerful Affirmations - Apps on Google Play
1000 Powerful Affirmations - Apps on Google Play
BruceK
Well-Known Member
For the Admiral's sake I have use fender flutes. However in that vid I think the fender line eye is around a cleat and the fender simply flipped over. Whatever is easiest for madam, I'm not overly perturbed so long as they are easily ready and not lost or banging about
BruceK
Well-Known Member
Portofino
Well-Known Member
Clue is in the thread title.
I don't see one in yours either, actually. If you just download one of the many apps available FoC, you can monitor your AoA in real time (as well as the reaction to trim tabs), down to a tenth of degree accuracy.
Not that I'm so maniac to do such check regularly, but I did and got some interesting results upon seatrial of my boat, and now I keep that in mind for fine tuning while cruising.
The word that begins with “ i “
Portofino
Well-Known Member
Reminding of what ?
I've shown you plenty already but if you need reminding:
Get yourself a copy of Linsays Lords book .”Navel architecture of planing hulls “ Oh and read it ...l.helps !
Cos it’s flat at the back , tech term tiny deadrise .
This is because it needs extra stern lift because the engines are butted up against the transom .
Its also ( needs them to over come the distance twixt CoG and CoF ) trim-able legs .
This is mostly why you need to reduce speed below your superchargers rpm when the sea picks up .
Don,t know why your vid has any relevance to a simple bowl of the dogs water, glorified spirit level ?
@ J rudge .l.sorry you find the tech stuff boring, there’s more to boats imho than down lights , griddles , patio doors , etc .
The basic principles of hull design , AoA , CoG , CoL , deadrise are found in many boats , a lot of builders try and stay close .
Having said that those that drift need calling out .
I don’t believe I am the only one who actually leaves the marina ?
But i do get it if folks just want a floating apartment because funds mean they can’t have both , a house + boat near .
Mr Googler
Well-Known Member
BruceK
Well-Known Member
I could conter your argument by pointing out by your own admission that you do not have space on your boat precisely because of it's design and yet to cater for it it is still a large boat with large engines to compensate for it and carries all the associated costs. One could possibly argue you have an overgrown day boat and massively overcompensating given the use you get and that is fine if that is what you want. The problem with no compromise is you get just that. A boat that is good at one thing but lacks the agility to be all things and that is superb if what you want to do is race. However I'd contest that yours doesn't even do that particularly well and so you are a jack of one trade and you hold that up as being the epitome of cruising and boat ownership.
Quite simply to counter your allegation that my perceived AoA was a trick of camera angle
You're lost in the past, and that is not dissimilar to reading a book on the principles of flight from the same era. Lets take a look at modern wave cutting designs. Would you call out the design behind Safehaven Marine's XSV20 fot being a radical departure from your optimum?
Then again you keep touting deadrise like it's the be all and end all when in fact if you look at your entry point to the wave you will see that your bow is quite bulbous where it meets the water on the plane because it needs lift
That Porto is not a wave piercing design and you have to shed vast volumes of water to smooth that ride. Maybe that is why you need a crippling dead rise with a half baked carolina flair to keep the helmsman dry.
On the other hand this is flatass
She has a much steeper entry and doesn't need lift to shed water as she parts it and so performs better bow down than bow up and not so reliant on a deep V, which incidently allows her smaller engines, greater efficiency more space blah blah blah read the makers notes and repeat them as gospel etc.
Again this is wrong, I reduce speed because it is prudent to do so in the conditions I sometimes have to boat in. This can be in a short chop of 1.3-5m with a 2 second period.
On it's own that is not too bad but in the local gyre with interference waves hitting a steep 3m wave or falling into a hole is admittedly more than what I'd want to tackle for the shitz n giggles or sometimes because I can get away with smaller engines I simply dont have the grunt to get to top speed in those conditions. But is my boat flawed? Like heck it is. OK there are bits that I mangled beneath the engine hatch but that's another story. You're a one trick pony so invested into your own belief system that you simply cant see that there are many designs that can achieve many ends and the naval architects trick is to blend those various designs not to create a master of one but a jack of all. In the meantime feel free to part the waves however you deem best but not off the backs and expense of your fellow boater.
Quite simply to counter your allegation that my perceived AoA was a trick of camera angle
You're lost in the past, and that is not dissimilar to reading a book on the principles of flight from the same era. Lets take a look at modern wave cutting designs. Would you call out the design behind Safehaven Marine's XSV20 fot being a radical departure from your optimum?
Then again you keep touting deadrise like it's the be all and end all when in fact if you look at your entry point to the wave you will see that your bow is quite bulbous where it meets the water on the plane because it needs lift
That Porto is not a wave piercing design and you have to shed vast volumes of water to smooth that ride. Maybe that is why you need a crippling dead rise with a half baked carolina flair to keep the helmsman dry.
On the other hand this is flatass
She has a much steeper entry and doesn't need lift to shed water as she parts it and so performs better bow down than bow up and not so reliant on a deep V, which incidently allows her smaller engines, greater efficiency more space blah blah blah read the makers notes and repeat them as gospel etc.
Again this is wrong, I reduce speed because it is prudent to do so in the conditions I sometimes have to boat in. This can be in a short chop of 1.3-5m with a 2 second period.
On it's own that is not too bad but in the local gyre with interference waves hitting a steep 3m wave or falling into a hole is admittedly more than what I'd want to tackle for the shitz n giggles or sometimes because I can get away with smaller engines I simply dont have the grunt to get to top speed in those conditions. But is my boat flawed? Like heck it is. OK there are bits that I mangled beneath the engine hatch but that's another story. You're a one trick pony so invested into your own belief system that you simply cant see that there are many designs that can achieve many ends and the naval architects trick is to blend those various designs not to create a master of one but a jack of all. In the meantime feel free to part the waves however you deem best but not off the backs and expense of your fellow boater.
markc
Well-Known Member
Thing is Porto, we know you love your boat 
, but surely the love of your own boat should't be a platform and an excuse to criticise everyone's boat and the choices they made. As far as I'm concerned, your boat is great, but it's got a sh!t flybridge... my flybridge is way better than your flybridge. What's wrong with you is that when you went boat buying you had no blimmin' idea what a flybridge looked like, so you ended up buying a boat with probably the most sh1t flybridge I have ever seen., Listen, don't worry, I have book on flybridges you can borrow so you can learn all about them so you never make the same mistake again 
, but surely the love of your own boat should't be a platform and an excuse to criticise everyone's boat and the choices they made. As far as I'm concerned, your boat is great, but it's got a sh!t flybridge... my flybridge is way better than your flybridge. What's wrong with you is that when you went boat buying you had no blimmin' idea what a flybridge looked like, so you ended up buying a boat with probably the most sh1t flybridge I have ever seen., Listen, don't worry, I have book on flybridges you can borrow so you can learn all about them so you never make the same mistake again
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mcanderson
Well-Known Member
Coming into to this late from an aero/hydrodynamics point of view. All the “rough” AoA indicators are nothing more than very rough attitude/pitch indictators. To get an AoA indicated you need to also show the change on the pitch to the inflow. This is very complicated and changes as the aerodynamic/hydrodynamic shape changes along any lifting surface.
Have a look at a SU35 cobra manoeuvre. Super high AoA (alpha) off a very aerodynamic wing surface, but the induced drag is huge. Thrust beats drag. When not pulling a high alpha manoeuvre it is a very slippery platform and has very little drag.
So attitude is not alpha and the two are linked but not the same.
Have a look at a SU35 cobra manoeuvre. Super high AoA (alpha) off a very aerodynamic wing surface, but the induced drag is huge. Thrust beats drag. When not pulling a high alpha manoeuvre it is a very slippery platform and has very little drag.
So attitude is not alpha and the two are linked but not the same.
MrB
Well-Known Member
I have always been fascinated with the agility of that plane but I do think thrust vectoring or TVC is is playing a huge part here. Also the wing is virtually stalled before thrust is applied so not a lot to beat. I do however bow out to your superior knowledge on this and think you are merely simplifying it for us. Bloody good analogy though.
