Wakesurfing: Some Wakes are More Equal than Others

Abstract

Recreational boat usage and ownership in Australia is at an all-time high. Every vessel that moves through the water generates wake waves. Of particular interest has been the proliferation of recreational vessels designed and manufactured for the sport of wakeboarding and more recently, wakesurfing (a popular alternative activity to wakeboarding). Wakeboarding/wakesurfing vessels are designed, through the use and control of ballast and customised trim, to maintain a breaking wave at the optimal operational speed (typically 10 knots for wakesurfing and 19 knots for wakeboarding).
The Decision Support System (DSS) developed by [6] provides a standard methodology for assessing the vulnerability of a shoreline to erosion, providing management recommendations on the likely impact of recreational boat wake waves along a waterway using an evidence-based approach. The DSS is underpinned by a database incorporating extensive field measurements of boat wake waves for water skiing, wakeboarding and wakesurfing activities. To test the hypothesis that wakesurfing waves are equivalent to wakeboarding waves, a series of field measurements were undertaken on three late model wakeboarding vessels at a range of operating speeds and ballast configurations. The tests were undertaken in a controlled environment (deep water, no currents, controlled boat speeds, repeat runs etc.) using state-of-the-art measuring equipment. The results of the field tests indicate that the wave energy associated with the single maximum wave height (Energy Hmax) for the wakesurf “operating conditions”, is approximately four times that of the wakeboard “operating conditions”, and twice that of the wakeboard “maximum wave” conditions.

Full text

Australasian Coasts & Ports Conference 2015
15 - 18 September 2015, Auckland, New Zealand
Ruprecht, J. et al.
Wakesurfing: Some Wakes are More Equal than Others
1
Wakesurfing: Some Wakes are More Equal than Others
Jamie E. Ruprecht1, William C. Glamore1, Ian R. Coghlan1 and Francois Flocard1
1 Water Research Laboratory, School of Civil and Environmental Engineering,
UNSW Australia, Manly Vale, Australia; j.ruprecht@wrl.unsw.edu.au
Abstract
Recreational boat usage and ownership in Australia is at an all-time high. Every vessel that moves through
the water generates wake waves. Of particular interest has been the proliferation of recreational vessels
designed and manufactured for the sport of wakeboarding and more recently, wakesurfing (a popular
alternative activity to wakeboarding). Wakeboarding/wakesurfing vessels are designed, through the use and
control of ballast and customised trim, to maintain a breaking wave at the optimal operational speed
(typically 10 knots for wakesurfing and 19 knots for wakeboarding).
The Decision Support System (DSS) developed by [6] provides a standard methodology for assessing the
vulnerability of a shoreline to erosion, providing management recommendations on the likely impact of
recreational boat wake waves along a waterway using an evidence-based approach. The DSS is
underpinned by a database incorporating extensive field measurements of boat wake waves for water skiing,
wakeboarding and wakesurfing activities. To test the hypothesis that wakesurfing waves are equivalent to
wakeboarding waves, a series of field measurements were undertaken on three late model wakeboarding
vessels at a range of operating speeds and ballast configurations. The tests were undertaken in a controlled
environment (deep water, no currents, controlled boat speeds, repeat runs etc.) using state-of-the-art
measuring equipment. The results of the field tests indicate that the wave energy associated with the single
maximum wave height (Energy Hmax) for the wakesurf “operating conditions”, is approximately four times that
of the wakeboard “operating conditions”, and twice that of the wakeboard “maximum wave” conditions.
Keywords: wakeboard, wakesurf, waterski, riverbank erosion, waterway management.
1. Introduction
The sport/recreational activity of wakeboarding
involves being towed behind a customised towing
vessel at elevated speeds (typically about 35 km/hr
or 19 knots) in a manner similar to water skiing. As
in water skiing, wakeboarding is usually
undertaken in low energy environments such as
inland waterways, ports and harbours. However, in
contrast to water skiing, wakeboarding involves
utilising the wake waves to conduct manoeuvres,
using the wash as a launching ramp. It is important
to note that the largest possible wake wave is not
necessarily the best wave for wakeboarding.
Typically, the optimal wake wave is one that is
large enough to provide a sufficient ramp for aerial
manoeuvres but that simultaneously contains the
optimal slope (i.e. wave shape) for approach. A
wave that is too big will break and thus not provide
the adequate angle for lift.
To maximise the amount of lift without creating a
breaking wave, wakeboarding vessels began to
use wake enhancement devices (WED). The
primary purpose of the WEDs is to increase the
speed at which the vessel can maintain its critical
Froude condition, thus ensuring that a large
displacement wave is generated at speeds of
between 12 to 19 knots. WEDs are now designed
to optimise wake waves by (i) increasing the
ballast in the vessel (either through inflatable water
bags or internal ballasting); (ii) modifying the hull
design; (iii) installing wedge platforms on the stern
of the vessel which impacts vessel trim; (iv)
operating at slower speeds then water ski vessels;
and (v) installing elevated towing platforms.
More recently, with sophistication in the design of
specialised wakeboarding vessels incorporating
WEDs, the sport has seen a rise in a popular
alternative activity to wakeboarding, being that of
wakesurfing. Wakesurfing involves creating a large
wake on one side of a boat that can be surfed
without a tow rope. The creation of a large wake at
the optimal operational speed (typically about
18 km/hr or 10 knots) is assisted by placing the
majority of the ballast near the aft (i.e. stern)
corner on the side the vessel to be surfed (biased
ballasting). Consequently, the wake generated off
the opposite side of the boat is considerably
smaller. The predominant factor that has limited
the popularity and growth of wakesurfing as a sport
has been the lack of boats capable of making
optimal, surfable waves at a safe distance behind
the boat.
The impact of boat waves generated from
recreational vessels on the shoreline has become
an increasingly important field of research
[2][4][5][6][8]. A significant step in understanding
the difference between boat wake waves
generated from wakeboarding and water skiing
vessels is presented in [5]. [5] presents the work of
[7] which measured wakeboarding and water
skiing vessel generated boat waves from
controlled experiments conducted on Manly Dam,
Sydney, NSW, between 2004 and 2005. The

Australasian Coasts & Ports Conference 2015
15 - 18 September 2015, Auckland, New Zealand
Ruprecht, J. et al.
Wakesurfing: Some Wakes are More Equal than Others
2
results presented in [5] show that the wave energy
produced by wakeboarding and water skiing
vessels is not significantly different. In fact, the
results contradict previous anecdotal evidence
regarding wakeboarding wave height which have
suggested wave heights >0.5 m [1][3].
However, how do these results compare with boat
waves generated from specialised wakeboarding
vessels equipped with WEDs designed to increase
the size and enhance the shape and location of the
wake for wakesurfing activities? Ultimately, are
wakesurfing waves equivalent to wakeboarding
waves? This paper provides the methodology used
to answer these questions and addresses the
implications of wakesurfing activities on current
best practice for shoreline management.
2. Methodology
The objective of the field testing program was to
accurately measure wake waves from three
different late model wakeboarding vessels
travelling at a range of speeds, to update and
expand the existing DSS database (for
wakeboarding and wakesurfing) and improve
statistical robustness. For this experiment, the best
practice methods outlined in [5] were again applied
for measuring wake waves. These methods
emphasise full scale testing of vessels using
multiple wave probes deployed at distinct
distances from the sailing line at a location without
strong currents or wind energy, with water
sufficiently deep so that the waves are not depth
affected. Importantly, this method is repeatable
and allows for subsequent comparison of wake
waves without external impeding factors and is
enhanced by extensive quality assurance checks.
The 2014 field experiments were carried on the
Clarence River, near the Junction Hill Boat Ramp,
in Grafton, NSW. The site location was selected
from a range of possible testing locations because:
• The river was moderately deep throughout (i.e.
waves would not be depth affected but it was
shallow enough for wave probe stations to be
deployed);
• The river bed at the site was very even (i.e. the
water depth was spatially constant)
• The river width was sufficient for deploying
three wave probe stations;
• The site was partially sheltered from wind
energy and, as such, the measurements were
not greatly influenced by background noise;
• During the test program, the site was not
influenced by strong currents that would affect
the measurements;
• The sloping shoreline (composed of complex
sediments and reeds) absorbed the majority of
the wave energy, thereby eliminating wave
reflections (which would be measured by the
wave probes);
• The site was located in a straight stretch of the
river which provided an optimal sailing line for
the approaching vessels; and
• At the time of the field testing program, erosion
was observed at riverbank sections in the
vicinity of the site location.
To measure the propagation of a wave train from a
test vessel, an array of equipment was deployed
across the site. A 250 m long sailing line was set-
up using four floating buoys. At distances of 22, 35
and 75 m from the sailing line, three submersible
wave probes were deployed. Each probe was a
battery powered RBRduo TD pressure transducer
which logged data internally at 6 Hz. Each wave
probe was secured to a portable mounting rig
composed of modular pipe lengths and a weighted
base. Following deployment, GPS waymarks were
taken at each sailing line float and each wave
probe.
During the testing program, two ‘Control’ vessels
were anchored approximately 50 m downstream
and upstream of the sailing line. The downstream
‘Control’ vessel used a calibrated radar gun to
check the speed of an approaching/departing
vessel prior to it passing the line of wave probes.
Note that vessel testing was undertaken
alternatively in both directions; upstream and
downstream (except for wakesurf testing which
was only undertaken in the downstream direction).
A laser rangefinder was used to accurately
calculate distance between the wave probes over
water.
The weather conditions throughout the testing
program were considered ideal. Wind speeds at
the site varied between calm and up to 5 knots.
There was no rain during the vessel tests. The
testing program was undertaken on a falling tide;
currents were slack at commencement (on
approximately high tide) and directed weakly
downstream at its conclusion.
For this investigation, three wakeboarding vessels
were tested on 9 May 2014 (Table 1). During
testing, each boat was operated by an
independent boat captain familiar with the vessel.
Each boat was tested under a range of trim and
ballasting arrangements.
To obtain a statistically robust data set, a
comprehensive testing program was developed.
Each vessel was tested at a complete range of
speeds including 4, 8, 10, 14, 19, 24 and 30 knots.
All vessels were tested with full ballasts (except 10
and 30 knots), without towing a rider and with 1 to
4 people onboard. Biased ballasting was used at
10 knots to undertake an examination of waves
generated in association with wakesurfing. Empty
ballasting was used at 30 knots for comparison
with waves generated by waterski vessels at their

Australasian Coasts & Ports Conference 2015
15 - 18 September 2015, Auckland, New Zealand
Ruprecht, J. et al.
Wakesurfing: Some Wakes are More Equal than Others
3
operational speed. Six replicate runs were
completed for each vessel at each speed (except
at 10 and 30 knots with only 3 runs each). This
resulted in a total of 36 test runs per vessel.
Table 1: Vessels Tested
ID Make-
Model Engine
(hp)
Length-
beam
(m)
Boat
Type
Wake/Ski
Speed
(knots)
at
Critical
Froude
Fnl=0.5
1
Malibu
Wakesetter
VLX (2014)
Indmar
409 6.55/2.53 Wake 7.8
2
Tigé RZ2
Platinum
Edition
(2011)
PCM
450 6.71/2.59 Wake 7.9
3
Super Air
Nautique
G23 (2014)
PCM
409 7.01/2.59 Wake 8.1
3. Data Analysis
Following the field testing program, the pressure
sensor data from each wave probe was
downloaded. Initially, a high-pass filter (>0.25 Hz)
was applied to the raw pressure data to remove
the tidal signal. Then the raw pressure data was
converted to water surface elevation time series
using the technique of Nielsen (1989), reproduced
in Equation 1.
(1)
where = water surface elevation corresponding
to the nth central gauge pressure reading (m); =
nth central gauge pressure reading (Pa); ρ = water
density (998 kg/m3); g = acceleration due to gravity
(9.81 m/s2); δ = sampling period of the data (1/6 s
≈ 0.17 s); yp = height of the pressure transducer
above the river bed (m); D = water depth (m);
(-); (-).
Note that the water depth at each wave probe
varied between 4.2 and 3.7 m on a falling tide
during the field testing program. Similarly, the
wave probes were located between 1.0 and 0.5 m
below the water surface during this time.
The converted water surface elevation data was
normalised to a distance off centreline and
low-pass filtered (<2 Hz) to remove high energy
wind noise. A series of customised program codes
were used to analyse the data for a range of wave
parameters including maximum wave height
(Hmax), wave period of the Hmax wave (Tpeak), wave
energy of the Hmax wave (Energy Hmax), total wave
energy of the wave train (Etot), number of waves
and other variables. A total of 108 data sets
(vessel runs) were obtained from the field trials.
However, wave parameters were not able to be
derived from the 18 vessel runs at 4 knots due to
the very small wave wakes produced (i.e. it was
not possible to differentiate between boat wake
waves and small wind waves for these tests).
To remove the influence of small wind waves
present in the boat wake data, the “significant”
wave height was set to 0.04 m (consistent with [7]).
That is, the minimum value considered in boat
wake wave analysis was 0.04 m and wave heights
smaller than this were excluded from calculations.
4. Results
Time-history plots of wake waves were generated
for each vessel run. The individual plots were
stacked for each wave probe to provide a graphical
representation of the wave train evolution over
time and distance. To help illustrate the findings
from the study, an individual wave trace from
Boat 2 at 19 knots is provided in Figure 1. The top
(red) line indicates the probe closest to the sailing
line (22 m), while the middle (green) line indicates
the wave by the time it reaches the middle probe
(35 m) and the bottom (blue) line shows the wave
at 75 m from the sailing line. In general, Figure 1
shows that while wave height attenuates with
distance, wave period remains fairly unchanged.
The wave traces also indicate that the total wave
train energy remains largely constant between
measurement probes.
Figure 1: Example Boat Wake Wave Trace.
It is apparent from the field trials that, regardless of
design differences, these vessels generate a
similar wave trace for a given speed. At 22 m the
wave is typically characterised by a large Hmax,
with waves bunched in a tight wave train. As the
wave train travels and disperses, generally the
number of waves increases and the wave height
attenuates. This becomes more apparent with
increasing distance from its point of generation. By

Australasian Coasts & Ports Conference 2015
15 - 18 September 2015, Auckland, New Zealand
Ruprecht, J. et al.
Wakesurfing: Some Wakes are More Equal than Others
4
the final probe (approximately 11.0 boat lengths)
the wave train is fully developed and, while further
attenuation of the wave height is likely, the wave
period should persist in deep water. The wave
height, however, may again increase as the wave
shoals onshore.
Results for important parameters, including
maximum wave height (Hmax), wave period of the
Hmax wave (Tpeak), wave energy of the Hmax wave
(Energy Hmax) are provided for comparison with the
previous round of testing undertaken at Manly
Dam between 2004 and 2005 [5].
4.1 Maximum Wave
Maximum wave height is the height of the highest
wave in the wave train. Since maximum wave
height decreases with distance from the sailing
line, the maximum wave height is measured at the
wave probe closest to the sailing line (22 m).
Table 2 summarises the average maximum wave
height (Hmax) measured at this probe for all three
boats tested. The highest average Hmax values
were recorded at 8 knots for wakeboarding
activities and 10 knots for wakesurfing activities.
Table 2: Average Maximum Wave Height (Hmax)
Speed
(knots)
No. of Tests
per Boat
Average Maximum Wave
Height, Hmax (m) (Boats 1-3)
8
6
0.27
10
3
0.38
14
6
0.24
19
6
0.22
24
6
0.19
30
3
0.13
4.2 Peak Wave Period
Peak wave period is used in this study to describe
the wave period of the highest wave (Hmax) in the
wave train. The peak wave period remains
relatively stable throughout the spreading of the
wave train (i.e. the peak wave period at each wave
probe is very similar). Table 3 summarises the
average peak wave period (Tpeak) measured at the
wave probe closest to the sailing line (22 m) for all
three boats tested. The speeds (8 and 10 knots) at
which the largest peak wave periods were
recorded largely corresponded with the speed at
which the highest waves were generated.
Table 3: Average Peak Wave Period (Tpeak)
Speed
(knots)
No. of Tests
per Boat
Average Peak Wave
Period, Tpeak (s) (Boats 1-3)
8
6
2.02
10
3
2.02
14
6
1.85
19
6
1.75
24
6
1.61
30
3
1.57
4.3 Wave Energy
The energy of the maximum wave height
(Energy Hmax) is a measure of the energy per unit
length of the single highest wave in a wave train.
Table 4 summarises the average energy of the
maximum wave height (Energy Hmax) across all
three vessels tested measured at the wave probe
closest to the sailing line (22 m) for the three boats
tested. The highest average Energy Hmax values
were recorded at 8 knots for wakeboarding
activities and 10 knots for wakesurfing activities.
Table 4: Energy of Maximum Wave (Energy Hmax)
Speed
(knots)
No. of
Tests per
Boat
Average Energy of Maximum
Wave, Energy Hmax (kg.m/s2)
(Boats 1-3)
8
6
595
10
3
1,219
14
6
379
19
6
286
24
6
175
30
3
90
5. Discussion
5.1 Wakeboarding Activities
Prior to the 2014 field trials, the vessel generated
wave energies included in the DSS were from
controlled field tests conducted between 2004 and
2005 by the Water Research Laboratory (WRL) [5].
Two typical wave conditions in the DSS associated
with wakeboard activities are classified as
“operating” and “maximum wave” conditions.
“Operating conditions” describe the waves
generated when a vessel is towing a rider at
operational speed (typically 10 knots for
wakesurfing and 19 knots for wakeboarding).
However, “maximum wave” energy is not produced
when wakeboarding vessels travel at “operating
conditions”, but rather at the slower speed of
approximately 8 knots. These are characterised in
the DSS as “maximum wave” conditions and are
experienced when a boat is accelerating, or
slowing down from operational speed. A summary
of the characteristic boat wave parameters based
on WRL testing in 2004/05 and 2014, for both of
these typical wave conditions, are provided in
Table 5. The Hmax and Tpeak values from each of
the 2014 tests (excluding the wakesurfing runs at
10 knots) are plotted in Figure 2 with each of the
same values from wakeboard vessel field tests
conducted by WRL in 2004/05.
The key information used in a DSS assessment is
the energy of the single highest wave in a wave
train (Energy Hmax) and the total wave train energy
(Etot). For the “maximum wave” conditions, the
average wave energy values measured in the
2014 field tests are slightly lower than those values
previously included in the DSS. This appears to be
because the wave energy of Boat 1 at 8 knots was
lower than Boats 2 and 3 at the same speed. The

Australasian Coasts & Ports Conference 2015
15 - 18 September 2015, Auckland, New Zealand
Ruprecht, J. et al.
Wakesurfing: Some Wakes are More Equal than Others
5
Energy Hmax and Etot values for Boats 2 and 3 are
approximately equivalent to the values presently
included in the DSS. For the “operating
conditions”, the average wave energy values
measured in the 2014 field tests are approximately
equivalent to the values previously included in the
DSS. Note that the average Hmax values in the
2014 tests are slightly lower than the 2004/05
tests, but that the average Tpeak values are slightly
higher for both typical wave conditions.
Figure 2: Comparison of WRL 2004-05 and Clarence
River 2014 Wakeboard Field Test Results
5.2 Wakesurfing Activities
Prior to the 2014 field trials, wave energies
generated by vessels undertaking wakesurfing
were not included in the DSS, although pilot field
trials of vessels undertaking wakesurfing were
carried out on Manly Dam in 2004/05. In 2004/05,
seven wakesurfing tests were comprised of three
runs by one boat and four runs by a second
vessel. Note that vessel speed was not recorded
for the 2004/05 wakesurfing tests. In 2014, three
replicate runs at one speed (10 knots) were
undertaken for each vessel. This provided a total
of nine measured wakesurfing results. For both the
2004/05 and 2014 wakesurfing tests, biased
ballasting was configured so that the larger wake
on one side of the boat was directed towards the
wave probes. The average Hmax, Tpeak, Energy Hmax
and Etot values from both wakesurfing datasets are
provided in Table 6. The Hmax and Tpeak values
from both wakesurfing datasets are plotted in
Figure 3. Note that the same scale used in Figure
2 has been used to emphasise the difference
between the wakesurf and wakeboard test results.
While it is acknowledged that there are a limited
number of wakesurf field test results available,
comparison of these two datasets indicates that
the parameters of the large wake waves
associated with wakesurfing are reproducible. On
a preliminary basis, a new vessel activity, wakesurf
“operating conditions”, was added to the DSS
database. The characteristic wave parameters for
this wave condition are provided in Table 7.
Figure 3: Comparison of WRL 2004-05 and Clarence
River 2014 Wakesurf Field Test Results
Comparing the characteristic boat wave conditions
for wakeboarding and wakesurfing as shown in
Table 5 and Table 7 shows that the wave energy
associated with the single maximum wave height
(Energy Hmax) in the preliminary wakesurf
“operating conditions” is approximately 3.8 times
wakeboard “operating conditions” and 1.6 times
wakeboard “maximum wave” conditions.
5.3 Total Wave Train Energy
[6] present an empirical relationship fitted between
the energy of the maximum wave height and the
total energy of the wave train for wakeboard and
waterski vessels that is used in the DSS to
estimate the total energy of the wave train where
the characteristics of the maximum wave are
known. On the basis of the 2014 field trials, this
relationship was updated in the DSS and can be
calculated by Equation 2.
(2)
A new power relationship for the wakesurf activity
(independent of wakeboard and waterski results)
was also prepared for use in the DSS as shown by
Equation 3.
(3)
Using these relationships, the energy of the entire
wave train can be multiplied by the number of boat
passes over a specific time period to give the
cumulative boat wake wave energy over a specific
duration (i.e. 8 daylight hours). Comparison of the
wake wave energies with the wind-wave energy of
the site provides an indication of the likely impact
of the boat waves on the shoreline.
6. Conclusion
The aim of this study was to objectively assess the
wake waves from several recreational towing
vessels through extensive field testing at various
speeds and compare the wave characteristics of
wakeboarding and wakesurfing activities. The
measurement of waves from each boat was

Australasian Coasts & Ports Conference 2015
15 - 18 September 2015, Auckland, New Zealand
Ruprecht, J. et al.
Wakesurfing: Some Wakes are More Equal than Others
6
undertaken using a standardised methodology
proposed in [7].
On the basis of the 2014 field measurements with
three additional late model wakeboarding vessels
equipped with WEDs, four major outcomes have
been developed, which may have implications for
waterway management. These include:
• The characteristic “maximum wave” conditions
for wakeboard vessels remain unchanged;
• The characteristic “operating conditions” for
wakeboard vessels remain unchanged;
• The test results for the three additional vessels
were added to the DSS vessel database which
slightly improved the correlation of the
empirical relationship fitted between the
energy of the maximum wave height and the
total energy of the wave train; and
• The wave energy associated with the single
maximum wave height (Energy Hmax) in the
preliminary wakesurf “operating conditions” is
approximately 3.8 times wakeboard “operating
conditions” and 1.6 times wakeboard
“maximum wave” conditions.
Operational wakesurfing has been shown to
produce significantly different waves to
wakeboarding and waterskiing. It is recommended
that these three activities be assessed and
managed separately. A common feasible
management option is to restrict those activities to
wide parts of the river to allow for natural wave
height attenuation. In certain situations, where
maximum wave height is a concern, and
insufficient distance is available to allow for natural
attenuation, management of the sport may result in
restricting activities or the implementation of
artificial shoreline enhancements (i.e. bank
armouring, rip-rap, rock fillets etc.).
7. Acknowledgements
The authors wish to thank the NSW Maritime
Authority and Clarence Valley Council, NSW for
their financial and technical support.
8. References
[1] Cameron, T. and Hill, P. (2009). Assessing the
Impact of Wakeboarding in the Williams Estuary, NSW
Australia- challenges for estuarine health. Proceedings
of 2008 River Symposium, Australia.
[2] Davey, E.K. and Glamore, W.C. (2013). A Tale of
Two Rivers. Proceeding of the 21st Australasian Coastal
and Ocean Engineering Conference and the 14th
Australasian Port and Harbour Conference, Sydney,
Australia.
[3] GHD (2006). Williams Riverbank Erosion Study. Final
Report, Port Stephens Council, NSW.
[4] Glamore, W. (2008). A Decision Support Tool for
Assessing the Impact of Boat Wake Waves on Inland
Waterways. On-Course, PIANC. October 2008 pp 5 –
18.
[5] Glamore, W.C. (2011). The Myth of Wakeboarding
Vessels and Riverbank Erosion. Proceeding of the 20th
Australasian Coastal and Ocean Engineering
Conference and the 13th Australasian Port and Harbour
Conference, Perth, Australia.
[6] Glamore, W.C. and Badenhop, A.M. (2007), Boat
Wake Wash Decision Support Tool User’s Manual, WRL
Technical Report 2007/22.
[7] Glamore, W. C. and R. Hudson (2005). Field
Investigation and Comparative Analysis of Boat Wash
Waves, WRL Technical Report 2005/10.
[8] Stumbo S, Fox K, Dvorak F, Elliot L (1999). The
prediction, measurement, and analysis of wake wash
from marine vessels. Marine Technology and News. 36
(4): 148-260.
Table 5: Characteristic Boat Wake Wave Conditions for Testing on Manly Dam and on the Clarence River
Location Boat/Activity Conditions
Speed
(knots)
Hmax (m) Tpeak (s)
Energy H
max
(kg.m/s
2
)
E
tot
(kg.m/s
2
)
Manly Dam
Wakeboard
Maximum Wave
8
0.35
1.86
700
2,325
Wakeboard Operating 19 0.25 1.57 293 1,138
Clarence
River Wakeboard Maximum Wave 8 0.27 2.02 595 1,874
Wakeboard Operating 19 0.22 1.75 286 1,075
Table 6: Average Wakesurf Boat Wake Wave Conditions
Testing Dataset Year
Speed
(knots)
No. of
Tests
H
max
(m)
T
peak
(s)
Energy H
max
(kg.m/s
2
)
E
tot
(kg.m/s
2
)
Manly Dam 2004-05 Unknown 7 0.34 2.04 950 2,278
Clarence River 2014 10 9 0.38 2.02 1,219 2,908
Table 7: Characteristic Wakesurf Boat Wake Wave Conditions used in the DSS
Boat/Activity Conditions
Speed
(knots)
Hmax (m)
T
peak
(s)
Energy Hmax (kg.m/s2)
E
tot
(kg.m/s
2
)
Wakesurf Operating 10 0.36 2.03 1,102 2,575