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Fine
Tuning For The Future
An
Evaluation of Aeromarine Research's Tunnel Boat Design Program
Article and Test by Greg Terzian and Helmut Freitag
Photos by Greg Terzian
We started with a
lightweight 1998 STV Euro, equipped with a factory stock Mercury 2.5 liter
EFI powerhead rated at 260 horsepower. We elected to use a stock powerhead
to better reflect the average hull/power combination this software might
face. Also, stock power is more consistent in performance, and will yield
greater accuracy for our purposes.
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Left:
Measuring
the outer sponson width.
Middle:
Measuring
the skeg width.
Right:
After
careful measurements are complete, it's time to hit the water. |
The first step was to accurately measure the
hull, as per the requirements of the Tunnel Boat Design Program. Although
some boat owners will already know their boat’s
details intimately, the measurement
process also became a learning process for me, as it no doubt will for
others. During this process, the user will become very familiar with the
components of a tunnel boat, as well as all facets of its
setup.
This process really helps you understand what features
make your tunnel boat perform as it does.
The measurements start off with basic hull attributes – sponson width,
deadrise angle, center pod properties, and so on. As on all the data input
screens, a diagram is supplied that shows the proper measurement points to
ensure accuracy. I found it most helpful to print the illustration, and
have it handy while making my measurements.
As you progress through the measurements, the
data input requirements become more involved, requiring weights, engine and
lower unit locations, lower unit measurements, maximum horsepower output,
propeller slip, and much more. One feature I found very helpful is the
preset lower unit measurements. Most lower unit configurations are covered,
and it saves the user the time of those measurements. Of course, if you
have a lower unit that is customized or unusual, you can manually input your
specifications
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Left and
Middle:
Helmut runs
the STV Euro to establish performance figures.
Right:
The Tunnel
Boat Design Provides us with its maximum velocity estimate - 115.1
mph. |
It is important to be accurate with your
measurements – which may require the help of others during the process.
As the Tunnel Boat software shows, it’s amazing how small dimensional
differences can really affect the performance of the boat.
The entire process of measuring the boat, cockpit, and setup characteristics
should take no more than an hour for the experienced tunnel boat
enthusiast. The software’s online help system and detailed diagrams go a
long way for those of us that are not very familiar with tunnel boats.
It’s then very easy to enter your boat’s design
dimensions and setup into the software.
When all of the measurements are completed and
entered into the Tunnel Boat Design Software, the real fun begins. This is
where the computer, predicting results on acceleration, velocity, and
stability, analyzes our virtual model of the STV. Before we tell you what
our computer told us, let’s run the boat first.
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Left:
Detailed
performance output data.
Middle:
Performance
Data Graph.
Right:
Stability
Data Graph. |
With Helmut Freitag operating the STV
Euro/Mercury 260 in optimum water and weather conditions, he was able to
achieve a top speed of 115.1 mph on the first run, and 115.4 mph on the
second run – all while noting the performance nuances and idiosyncrasies of
this rig. We had our top speed numbers, with our optimum setup. Let’s see
what the Tunnel Boat Design Software predicted:
With the data already saved in the software, a
simple mouse click on the “Calc Perform” button provided us with the output
of the software’s analysis. The result? Astonishingly, the Tunnel Boat
Design Program predicted that our setup would achieve a maximum velocity of
115.1 mph! Taking this even further, the TBDP
also accurately predicted our acceleration model – a big plus for drag
racers. The software noted that our rig would accelerate at a constant rate
up to about 103 mph, and that from 103 to 115 mph the climb would be much
slower. This prediction was within 5 mph of our performance with the STV,
as we noted that our STV began to “crawl” to 115 mph at about 108 mph.
Impressive accuracy, to say the least.
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Article Information |
| Aeromarine
Research presents the tunnel boat enthusiast, designer, and
racer with a software package designed to allow never before
possible design analysis of tunnel boat hulls. |
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Created: |
| September 23,
2001 |
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By: |
| Greg Terzian |
| Helmut Freitag |
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Category: |
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Product Evaluations |
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Manufacturer Website |
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aeromarineresearch.com |
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