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  #16  
Old 07-06-2007, 08:29 PM
igo2c igo2c is offline
 
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Someone had to ask...

First, I'd like to say that it's great having Jim Russell answer questions about recreational boating (if you're not familiar with Jim's background and accomplishments, check out the Aeromarine Research website).

I can only speak for myself as far as speed is concerned. Driving my Hydrostream, I really only run the boat flat-out for about 10-20 seconds, usually at the end of an evening boat ride. It just feels good to air the thing out, with that big ol' Merc' howling away back there. It's a lot like landing an aircraft. Things are happening fast, and the only thing on your mind at that time is the boat and what it's going to do next. The race boat (350 cc hydro) is a different story. I'm an engineer, and I spend hours and hours on the rig maintaining, tuning, machining, etc. for a few minutes of actual seat time. I enjoy those hours in the shop a lot, as much as I enjoy hanging the boat through a turn and pulling the pipes for the straight. I guess that without the challenges involved, it wouldn't be any fun at all.
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  #17  
Old 07-10-2007, 12:24 PM
messabout messabout is offline
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Jimboat and Igo2C are right about the thrill, the adrenaline rush or whatever it is. A whole lot of people seem to be compelled to do things that are not entirely consistant with common sense. Some of them even mortgage the farm to finance their pursuit. High rock climbers, skydivers, polar expeditionists, auto racers among others do some irrational stuff.

I run a shop that does air flow research and developement. That's a fancy way to say that I work on cylinder heads and intake tracts for guys who have the need for speed. In that game, I am accosted by every concievable kind of testosterone charged goober. Since I have become old and crotchety, I am selective about those for whom I might do work. Too many prospective customers do not have any idea of what they are letting themselves in for. More than a few of them are a real and present danger to society. They are going to gas up their 500 HP Mustang or 200 HP Hyabusa in rush hour traffic.

Recently there was a guy with a fast boat, the kind that anyone can buy if he has enough money. Brains not required. He was flying up a local bayou that had a switch back turn. He misjudged the turn, jumped his boat over a wake, jumped a 4 foot high dock and destroyed a bait house that had been turned into a waterfront apartment. The building was run clear through. The building was old, grandfathered in such that it could remain in a high end neighborhood. Too bad for the owners of the idyllic dwelling. The rebuilding permit could not be issued because of zoning regulations. The lone driver of the boat was taken to the hospital and did not have life threatening injuries. He'll probably buy another fast boat. Episodes like this one prompted me to ask a question that may be unanswerable.

The respondents in this thread would seem to be both sane and informed (not neccesarily including myself). When I asked the question about why we need to go fast, it was intended as an esoteric inquiry. I had hoped that there might be a clinical psychologist or behavioral scientist in our midst who can comment about our shared fixation.
If not then I will continue to languish in ignorance.

To all you good guys: be careful out there where lunatics abound.
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  #18  
Old 07-10-2007, 06:26 PM
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marshmat marshmat is offline
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Quote:
The respondents in this thread would seem to be both sane and informed (not neccesarily including myself). When I asked the question about why we need to go fast, it was intended as an esoteric inquiry. I had hoped that there might be a clinical psychologist or behavioral scientist in our midst who can comment about our shared fixation.
If not then I will continue to languish in ignorance.
Interesting question, and one that I'm sure the average university library has plenty of journal articles on. Perhaps we could start a thread on that matter?
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  #19  
Old 07-13-2007, 11:41 AM
messabout messabout is offline
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Point taken,Marshmat. My rambling was way off topic but does have a roundabout connection.
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  #20  
Old 07-25-2007, 12:18 PM
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Jimboat Jimboat is offline
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Chine Walk Photos

If anyone has any good photos that show chine walk or hull balancing, let me know, and I will try to include some of your boats in the finished Article.
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  #21  
Old 08-01-2007, 02:59 PM
fastpowerboats fastpowerboats is offline
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I agree with above comments - I think that solid mounts and hydraulic steering are a must.

Jimboat, I don't have pictures, but I would sure like to see some photos of flying vee boats! Also, good article!
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  #22  
Old 03-02-2008, 03:47 AM
sinus sinus is offline
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Hello;




Nice "old" tread!

I have few theorize questions round chine walking in example of boat with this aprox. datas:
- lenght 28 ft.
- wide10 inch.
- V hull 24 degrees at transom.
- notched transom 0,5 ft in lenght.
- pad keel, wide 6 inch, "V-hull" of pad keel 20 degrees at transom.
- static horizontal CG betwen 30-33% of boat lenght.
- boat height max 6,1 ft.
- two props cca 0,5-1 inch above geometric water surface.
- three longitudinal strakes on hull side, first one at the pad keel it is deducted 6,7 ft before transom.
- strong hydraulic drive steering.


1.) Is it china walking at light boat stronger and faster than at heavy boat if they "flight" with same speed?
2.) Is it boat with pad keel more sensitive for china walking?
3.) Have diference of 3 or 4 blade props bigg influence on china walking?
4.) Is it for really light boat in this dimensions better 22 than 24 degree V-hull at transom?
5.) Is it for this thing more dangerous higher or lower static CG?


bye
Saso
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  #23  
Old 03-02-2008, 07:39 AM
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Jimboat Jimboat is offline
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sinus - you have some good questions. you can find the answers to all of your questions in the article "Chine Walking" (HotBoat Jan 2008 issue).

call or PM me if you have any questions.

/Jimboat
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  #24  
Old 03-02-2008, 12:48 PM
sinus sinus is offline
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Hello again;



Is my understanding of next troubles correct?


I understand "china walking" like result of:

- lever betwen CG, weight of engines, other heavy parts and distances to CG.
- distance betwen CG and tuch point hull/water (CG lever).
- vertical distance betwen CG and pad (lever again).
- outside factors like wind, waves, bad sterring sistem, week, elastic montage of drive, props causes (wrong X montage, wrong props etc) ..., which start with oscilation and boat move round CG like pendulum with shaft on the bottom.



- with low Cg you have smaller levers and troubles must be smaller.
- with smaller weight of boat parts you have smaller levers, but same time smaller damper forces. Could this thing bring smaller and faster socilations, which start faster, but they are not so dramatic? Heavy parts like engines mounted high and far behind work like mace in knight hands and when it start...
- pad keel cause with his lift afact boat more sensitive to china walking, but same time it have stabilizing sharp edge, so?
- if have boat all edges sharp enough, it will go faster and more safety becouse of stabilizing and water cutting efect of this edges?


Is it possible to make superficialy parallel with big high car, which have bad suspensions and heavy motor in back and it is driven by back whells?



Sorry for my English! i try and try, but in school I did not work enough with languages and this is resultat. I hope, that somebody will understand what I would like to know.




bye
Saso
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  #25  
Old 03-02-2008, 08:13 PM
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Ike Ike is offline
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All good responses here, especially Jimboat. Just add one thing (yes I know I am being a wet blanket) but putting an outboard on your boat that exceeds the manufacturers rating can result in all kinds of things. NO It is not illegal under Federal Law. The Coast Guard will not cite you for it. But some states have laws making it a violation to exceed any value on the capacity label. I don't think Florida is one but you might want to find out.

Additionally should an accident occurr (assuming you have insurance) your insurance company probably won't pay up simply because the engine exceeds the rated hp.

If you have an accident and get sued, the court will almost automatically consider that big engine as evidence of negligence. You can bet their attorney willl make a big deal of it.

Got it wrong. Florida does have such a law. Here's a quote from the Florida Boating Law web site
MAXIMUM LOADING AND HORSEPOWER

"No person may operate a monohull boat of less than 20 feet in length while exceeding the maximum weight, persons, or horsepower capacity as displayed on the manufacturer's capacity plate."
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  #26  
Old 03-05-2008, 05:03 AM
sinus sinus is offline
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Hello;




Have somebody idea which pad keel it is at 24 degrees V-hull more dangerous for chine walking?

a.) Flat bottom pad keel.
b.) Pad kell with 18-20 degrees V.



@Ike;
In our region it is against the law if you exceeding factory datas of horse power and nobody will give you driwing licence for this boat!

Please do not take my questions like something from adrenalin junkie! I just want to know a little more about this phenomenum.





bye
Saso
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  #27  
Old 03-05-2008, 06:16 PM
mig74 mig74 is offline
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Much Better

hey guys, glad to see this post has survived! i finally got some more seat time with my boat, and i gotta tell ya, i can see where i was making my mistakes during trimming and using the hydraulic jackplate. i was using too much trim and not jacking the motor up enough. the more seat time, the more i got to know where the sweet spot is. thanks to everyone for their input. jimboat ill try to post some pics of the boat-aired out- for ya! anyhow,thanks alot guys-great forum.
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  #28  
Old 05-11-2008, 08:19 AM
smokeonthewater smokeonthewater is offline
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same solutions for jet boat?

Hi
Just read thru' this thread with interest (and will request a copy of your article by email in a min Jimboat)

I have a 16' boat that i belive is a Delta Clubman (it has no identification plates that i can find but thats what the preivious owner said it was), fitted with a jet drive system and a 200hp V8 engine. I have problems with this chine walking on calm days when you get to about 65/70 mph as well.
Most of the information provided so far has been regarding the trim or position of engine which i cannot change.
Once on the plain the boat rides very nicely and quite level but starts to snake from side to side when you get to a certain speed as the boat starts to rock from side to side.
Could someone please explain more about these "strakes" that were mentioned, or any other mods which could help stop this happening.


Cheers
Ed

P.S. The hull is un-stepped and i thought that this was to help stop turbulent water from entering the jet drive. (dont know if this would make any odd's or not)
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  #29  
Old 05-22-2008, 02:01 AM
NADreamcatcher NADreamcatcher is offline
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adding strakes to a vee bottom

Adding lift strakes on the bottom of a jet drive boat may work but on a high flying pad vee bottom they may actually hurt. I think they are called lift strakes because thats what they do, they lift the hull farter out of the water...that is if it's not already on the pad. someone correct me here if iam out to lunch. Tight steering and drive it through the bad spot...when the right side of the boat drops pick it up with the right side of the wheel and return back straight...and vica versa...does not take much just a little practice. don't be too agressive with the steering, when you sense it going just pick it up a little. I prefer to mash the throttle and drive through it as fast as possible. high flying vees need a driver capable of understanding and having the ability to use the steering to fly it level...or out you go!

bigger motor, more trim, mash it and go! sooner or later it will get ya!

NAD
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  #30  
Old 05-25-2008, 02:21 PM
smokeonthewater smokeonthewater is offline
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I have fitted some small home made trim tabs to the boat and it seems to have made some difference, they are just simple metal flaps that i can adjust using a thread and lock nut, i will do some more experimenting and i think i will just try to get enough trim to lift the back higher but not cause to much drag. I'll not be out in it for a while now but will see how well it works later on in the year.
Cheers Ed

P.s I dont really know enough about boat design or construction to start altering the hull and think it would be a shame for any of my (possibly suspect in quality and design) aleterations to the hull making a dog out of what is actually a really good boat!

Last edited by smokeonthewater : 05-25-2008 at 02:25 PM. Reason: added a P.s
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