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How to setup your new outboard tunnel By the International Waters

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How to setup your new outboard tunnel By the International Waters Powered By Docstoc
					                   How to setup your new outboard tunnel
                            By: the International Waters Outboard crew



This document is the Brain-child of International Waters member, TimD. With all of the outboard
"pros" on the forum, he thought it would be simple to get all of the crew to chime in with their
secrets for a first time setup. Like the old saying goes; "You can lead a horse to water but you
can't make him drink", a number of people commented on the thread but the heavyweights didn't
show up...perhaps we newer guys did a good enough job! What follows is a consolidated version
of the recommended way to setup your new outboard tunnel hull.


This is starting from the assumption that your boat is ready with the exception of the engine. Grab
your engine, or preferred, just the lower unit with the mount already installed, place the mount
against the transom and set the midline of the prop shaft at 1/8 inch or 3.2mm above the bottom
of the sponsons. Mark the holes in the transom at the middle of the engine mount slots. Doing so
will give you maximum adjustment up and down for different props or lower units. If you never
remove the mount or always use the same lower unit, you'll probably never have to adjust the
engine height as 1/8 inch above the sponson bottoms is very close to optimum height for all 3.5cc
tunnel hulls. Once the complete engine is mounted to the transom, set the Center of Gravity
(C/G) statically for 33% as measured from the rear of the sponsons. My daughter has ridged ruler
that is more accurate and safer than using your fingers. Add weight where needed to get the C/G
close...exact is not critical. Adjust the thrust angle at 0 degrees and prop mid-shaft height at 1/8
inch or 3.2mm above the bottom of the sponsons. Note the setup in the picture below.




At this point, you're almost ready to go to the water and fly your new hull. Before you do though,
be sure to mark these items on your checklist:

-Insure you have full throw for your throttle, forward and brake (shutoff)

-Set steering rate for max, you can adjust it down as necessary later. A contributing member
comments: "The only thing I like to see in set-up with the steering is work out the amount of lock
you need to turn on the bouys (you don't really need anymore). Set that to be the maximum
steering on your boat and you shouldn't run into the problem of hooking or spinning out - this
happens mostly through overdriving the boat..."

-Go over every screw, bolt and cable connection to insure they are tight and true. Many a
first run has gone sour due to a loose connection.

-If you're breaking in a new engine, I recommend doing so on a hull you're familiar with, especially
if you are a new boater. When everything is new, there are to many variables that could make a
disaster of a grand occasion. If you can't use a different hull, follow your engine manufacturer's
directions. Make a note of the speed/handling changes as the needle goes leaner.

-When you get to the water and before you start your engine, go over every screw, bolt and
cable connection to insure they are tight and true. Yes, I put that in twice intentionally for
emphasis. Take the hint, these are not toys! Once you're sure the boat is ready, start the engine
and set it in the water. A tunnel does not need to be launched or tossed! Run the boat at 1/2
throttle until you get a feel as to how it's going to run. If it feels smooth, increase the speed as
your setup is going to show any problems as speed gets faster.
Here's the solution to a common problem. If at a fast speed, around 40+ mph, the boat starts
porpoising when running straight, the propellor is to high. What is happening is the prop is
"blowing out" of the surface tension of the water and the weight of the hull is pulling the boat back
down to the surface. Lower the height in 1/16 inch or 1.5 mm increments until the porpoising no
longer occurs at high speed. What you are shooting for is maximum engine revolutions with good
stability.

When making turns, many boaters think it's cool to see how sharp they can turn their boat at a
fast speed. This is usually where the boater would complain about the boat hooking or spinning.
While cool, it's not how you turn in a race. Many newer hulls like Grimracer's Villain or JD's WOF
series boats were designed to race. Be easy on the steering and your setup will be good to you.
Steer the boat to make turns with a radius of about 30 feet or 9 meters, you will be impressed.

Grimracer recommends that after the boat is trimmed and running well, don't just drive around but
rather drive around something. He also commented that one should "Drive Drive and Drive the
boat some more". More stick time gives you a better understanding of the boat in different
conditions.


Another member recommends when running a new boat, start with a prop that is one size smaller
than what you will race with. He says it allows him to get on and off the throttle easily and know
what the boat will do under acceleration. Typically on a .21 he uses an X438 to start off with then
go up to an X440 later. The other thing he tries hard to do is just make 1 change at a time - then
run it to see what effect the change made. A different member echoes this comment for any
newcomer (and experienced) that comes into the hobby. He recommends against going home,
making 6 changes hoping for a record setup. "Not gonna happen." He goes on further to say that
you don't have to run an entire tank of fuel after every change, only run it long enough to see if it
worked or not. Then bring it in and make another change....doing so makes it less likely that
something bad will happen to the boat before you find the sweet spot. This thought is taken a
step further by a recommendation that you should only run the tank 1/2 full when testing. He
strongly feels that running a full tank everytime you change something is a waste of fuel. Take
two or three laps, try another adjustment, and repeat. After a while the adjustments become
second nature and you will have developed a knowledge of what effect it has on your boat.
Another point is that a boat with a full tank does not accelerate as fast or steer as quickly as one
that's almost empty.

Here is one that has to do with the driver of a new hull:
it's real easy when your splashing your hull for the first time to "White Knuckle it all the way
around" Relax, do a couple laps slow and build heat in the engine, then nail it on the straight, back
off a smidge as you enter the corner to set the sponsons and see how the hull's gonna react.
Try to take a few mental notes of how the hull is gonna react in race conditions.


We have looked at suggestions for making changes for setting up and tuning your boat but how
do you keep track of those changes?

Keeping a log is recommended. Nothing fancy...a little notebook will do fine. Write down what you
change or modify, and what effect it has. Keep track of things like nitro content, prop, plugs, pipes,
trim settings, etc. It can be very simple or very elaborate (to include engine mods, prop mods,
weather and water conditions, etc.) At the end of a day of testing, you can look back over your
notes and get an idea of what's working, what's not, and what to try next. It's also a lot less
frustrating than trying to remember what you changed between outings. Once you find that sweet
spot for your setup you need to document your setup. One suggestion is that you "drill a small
hole large enough to put a piece of wire through." This way, if you do some adjustments later or
have to remove the motor for some reason, you can go right back to the previous setting.
In closing, Grimracer has a few words:

First, this is fun and that is the bottom line. If I were speaking to a newcomer, I would ask them if
they think that there is a chance that they might race their boat in the future (most of the time its
no). To give a reason why a new boater is reluctant to race is because they are intimidated.
Snowdog says; "I was asked way back when I was in Dayton, Ohio in '88-'89 if I was going to race
my Prather Fast Cat/K&B 3.5 boat and I answered "no" because I was intimidated. If they had a
mentor, someone to describe and coach them in an event, they would be more willing! That's
what JD did with me and I've been hooked ever since!"

Next Grimracer would make sure that their setup is sound. That is to say that the darn thing is
going to go around the pond lap after lap with out something falling apart.

So, fellow racers, be friendly to newcomers, coach and guide them. Take them to a race and
introduce them to the club members and hook them up. You'll not only give the hobby's next
superstar a chance, you'll also give yourself competition in getting to the finish line first.




Slideblues

Great Idea!!!
One: Make your radio box movable, I run mine in a tray and run industrial strength velcro to hold
it, that way its easy to adjust for CG etc. I dont add any weight unless there is no other way to do
it, move the stuff already there around till it comes in where ya like it.
Gene


Snowdog

Two: Since we're on the subject of radio boxes. I'll share an idea I learned from JD.
Make it so the radio box is removable...even better, make them all the same so you can switch
one with another if you run into problems at a race or where time is of the essence.




GTR

Hi Guy's

I second what SD has said. The only thing I like to see in set-up with the steering is work out the
amount of lock you need to turn on the bouys (you don't really need anymore). set that to be the
maximum steering on your boat and you shouldn't get into the hooking on bouys - this is mostly
through overdriving the boat, or design flaws which I'm not knowledgable enough to comment on.

I think JD summed it up pretty well on one post - just run, run, run the boat. There is no substitute
for being totally familiar with your boat. When it starts to do something strange you will recognise
it.
TimD

OK now the thread is taking the direction I intended!
One thing I always try to do with a new boat is start with a prop that is maybe 1 size smaller than
what I'd eventually want to race with. This allows me to get on and off the throttle easily and know
what the boat will do under acceleration. typically on a 21 I'd use an X438 to start off with then go
up to an X440 later (1440's are a different story - won't go there for purposes of keeping the article
simple and to the point).
The other thing I try hard to do is just make 1 change at a time - then run it to see what effect the
change made.
Now it's someone else's turn.


Topfuel443

Thats a VERY KEY point for any newcomer (and experienced) that comes into the hobby, Its very
easy to get frusterated and go home to work on the boat, only to change 6 different things hoping
for a record setting boat on the next trip out. Not gonna happen.

Take it ONE step at a time.

You dont have to run an entire tank of fuel after evry change, only run it long enough to see if it
worked or not. then bring it in and make another change....also less likely that the boat will break
before you find the sweet spot youare looking for.


GTR

One other thing that I like to do is when trimming the boat I like to use the tank half full.
Depending on where you have your tank (I like mine on the CoG) it can have a huge effect on
handling. The half full tank is a good compromise point to do the trimming against. I also totally
agree that running a full tank everytime you change something is a waste of fuel - hence the half
tank approach. Two or three laps, try another adjustment, same again. After a while the
adjustments become second nature and you will have developed a knowledge of what effect it
has on your boat.

Other obvious point a bioat with a full tank does not accelerate as fast or steer as quickly as one
that's almost empty. Mind you it's also not as flighty on the water either.


Shane2 (guest)

Wow this is all great info. I cant wait to try some of these tricks out when I get to the pond this
weekend. I have already done some slight hull tweaking but the wind kicked up a bit too much to
asses the differences. Basically it sounds like anything else. When I raced off-road 1/10th scale,
we tweaked, ran a timed lap, tweaked again ran again etc. One thing I noticed is that when
tweaking a certain aspect (such as rear sway bar stiffness) go all the way to the opposite end of
the spectrum and then adjust back towards your starting point so you have a good idea of the
effects, and range of adjustment. Plus with this method, you go beyond the JND (just noticeable
difference) and you can decide right away if you are adjusting in the right direction.

Keep it coming! Us noobs are absorbing it all!
TimD

Shane,
Thanks for your comments! I'm glad you like the concept of the thread.

I'm hoping we can keep this thread going for a while and get as much information as possible -
will make for a great tech. article for the site that we can refer people to.

I'm surprised that we haven't heard from JD yet - he's probably setup more new hulls than all the
rest of us combined! And all the other tunnel guru's out there - have anything to contribute? I
don't want to name name's to offend anyone I forget to mention but most of the regulars here
know who I mean and want to hear your tips!
Tim.


Snowdog

Yes JD has setup many a hull and I'm sure JD would love to contribute to this thread. The only
problem is he's forgotten everything he would want to write.


PropJockey

Keep a log. Nothing fancy...a little notebook will do fine.

Write down what you change or modify, and what effect it has. Keep track of things like nitro
content, prop, plugs, pipes, trim settings, etc.

It can be very simple or very elaborate (to include engine mods, prop mods, weather and water
conditions, etc.). At the end of a day of testing, you can look back over your notes and get an idea
of what's working, what's not, and what to try next.

It's also a lot less frustrating than trying to remember what you changed between outings.


Eric Perez

 like the one change at a time approach also -sometimes I don't get to follow the "golden" rule all
the time because of lack of time. In the long run it all works out.

What do you guys use to measure strut height and angle on your boats? Any pictures would be
great!


Ron Olson

One thing that I've heard of but have yet to use is once you find that sweet spot on your outboards
angle is to drill a small hole large enough to put a piece of wire through. This way, if you do some
adjustments later or have to remove the motor for some reason, you can go right back to the
previous setting. I'd wished that done that on my tunnels. My DPI 7.5 was one of the first good
hulls pulled from the mold and the plans were not the final ones. I spent a lot of time and money to
find the right setup.


Slideblues
Here is one that has to do with the driver of a new hull:
Me and Grim were just talkin bout this the other day, its real easy when your splashin your hull for
the first time to "White Knuckle it all the way around" Relax, Do a couple laps slow and build heat
in the engine, then nail it on the straight, back off a smidge as you enter the corner to set the
sponsons and see how the hull's gonna react.
Try to take a few mental notes of how the hull is gonna react in race conditions.


Grimracer
Here is my take on this:

First this is fun and that is the bottom line.

If i were speaking to a new comer i would ask them if thy think that there is any chance that they
might race there boat in the years ahead. (most of the time its no).

Next i would make sure that there setup is sound. That is to say that the darn thing is going to go
around the pond lap after lap with out something falling apart.

As for as set up go im thinking that Snow has it right...Rock On snowdog.

At the pond my advice would be to not just drive around but rather drive around something.

And like Gener said.. Easy up freinds the race is not won on the first corner. Take it easy and
learn the boat.

Drive Drive and Drive the boat somemore..

Grimracer


Snowdog

Grimracer...thanks for the compliment. To give a reason why a new boater wouldn't race is
because they are intimidated. I was asked way back when I was in Dayton, Ohio in '88-'89 if I was
going to race my Fast Cat/K&B 3.5 boat and I answered "no" because I was intimidated. Perhaps
that's why new boaters are reluctant! If they had a mentor, someone to describe and coach them
in an event, they would be more willing! That's what JD did with me and I've been hooked ever
since!

				
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