INDEPENDENT SURF SYSTEM STUDY

by Jim Dowd and Dr. Steve Zalek

Mastercraft Gen 2 vs Malibu Surf Gate

An expert, independent study comparing the performance of two of the most popular wake surf systems

August 2014

Introduction

Independent Surf System Study - Mastercraft Gen 2 vs Malibu Surf GateAugust 2014

Study Conducted By:

Jim DowdJim is a senior consulting, product development and R&D professional with more than 30 years of experience in the transportation industry in Europe and the US. Jim has served on Technical Advisory Boards and his skills in new product creation have been recognized with the award of more than 20 US patents.

Dr. Steve ZalekSteve is the President of SeaSystems Research LLC and also the Associate Director of the University of Michigan Marine Hydrodynamics Laboratory.

Background

The subject of this comparative consumer study is a watersport known as wake surfing which is performed behind powered towboats. With wake surfing the surfer trails behind a wakeboard boat, surfing the boat’s wake without being attached to the boat by a tow rope. In particular the study compares the performance of 2 of the most popular surf systems on the market, that is the Mastercraft Gen 2 system and the Malibu Surf Gate system.

Wake surfing is an exciting sport for the general population, not just because it brings the experience of surfing on the ocean right to your local lake, but because it is so easy for riders of all ages to have fun behind the boat. The popularity of wake surfing has been increasing over recent years and in response to this, the different boat makers are coming up with innovative solutions in wake surf systems. As these companies vie for a leadership position, they have depended on consumers and athletes to provide valuable user feedback but some of the talk has created a lot of misunderstanding among consumers. With this unbiased and independent study, we are bringing science and objectivity to the comparison of surf systems.

Mastercraft and Malibu were chosen as the 2 benchmark boat companies because between them, their surf system equipped boats represent by far the largest share of the market. Boats from each of the following size categories: 20/22 foot, 23 foot and 24 foot were compared for performance.

Summary of Tests Performed

Boats:In the 20/22 foot boat category, the surf system on the Axis A22 from Malibu was com-pared to the surf system on the Mastercraft NXT. The 23 foot comparison was between the Malibu 23 LSV vs Mastercraft X30 and finally the Malibu 24 MXZ was matched up against the Mastercraft X46.

Mastercraft Gen 2Photo credit: Mastercraft.com

Malibu Surf GatePhoto credit: Malibuboats.com

Mapping the wave:The boats were loaded with factory ballast according to the manufacturers recommend-ed settings and adjusted for surfing on port and starboard sides. Using a combination of cameras, floating markers and sensors we were able to collect data points on the wake size and length. The markers rode the surface of the wave and the cameras, using special software were able to pick up the marker points and triangulate the distance to those points. Then by passing a mesh through those points we were able to map the sur-face of that wave. As can be seen from the images, the wake moves forward and side-ways creating an arc as the wake spreads backwards getting smaller the further away from the boat.

Mapping the wave continued:

Measuring PushThe phrase ‘push’ of the wake is a generally accepted term that describes the sensation that the surfer feels propelling him or her along behind the boat. There are lots of forc-es contributing to ‘push’ but the greatest force is gravity that comes from a high wake. The further away from the boat the wake gets, the smaller the height of the wake as it interacts with other water that isn’t moving. Eventually there is no ‘push’ and the surfer sinks. Techniques such as pumping can be used to bring a surfer back into the surf zone.

Using a young amateur surfer we were able to determine the area of push by using a rope that was instrumented to measure force. Where he was propelled by the wake without any strain in the rope, there was enough ‘push’. And when he had to hang onto the rope in order to stay up with the boat then there was not enough ‘push’.

Measuring how long it took to switch from one rider to another:It’s very convenient for everyone in the boat if it is easy to switch from a rider who surfs on the starboard side to one that surfs on the port side and vice versa. So we mea-sured in time how long it took to switch each boat from surfing on one side to the other. Most surfers when they are learning can only surf on one side of the boat wake with their toes pointing to the wake.

User interface:The user interface was also evaluated to determine how easy it was to set up the boat for wake surfing. Each boat comes with its own unique set-up procedure and control system that lets the consumer set the boat up for wake surfing. The easier those controls are to comprehend and the fewer clicks or steps that are required to operate the system, the better the system is for control. We looked for visibility of system status, easy-to-access exits and an easy-to-see home button. We also looked for persistence of wording and comprehensibility/intuitiveness. Finally we counted the physical number of steps needed to begin surfing.

Steering handling when using surf system: The steering handling of each boat was also evaluated while surfing. When you are driving a boat at surf speed and switch from creating a surf on one side to the other, the boat will change direction. The amount of steering wheel correction needed to keep the boat on course

was measured. The amount of force that needed to be applied to the steering wheel to make this correction was also measured.

Other performance metrics:Several other performance attributes that are important to consumers when considering overall wake system value proposition were measured and these include:

• Fuel efficiency when surfing.• Degree of drag caused by the system resulting in increased RPM.• Air quality and specifically determining levels of carbon monoxide exposure.• Noise level at surf speed measured inside and behind each boat.• How much each boat pitches and rolls as a result of deployment of the surf system.

SUMMARY OF SURF SYSTEM TESTRESULTS COMPARING

AXIS 22 vs MASTERCRAFT NXT

MALIBU 23 LSV vs MASTERCRAFT X30

MALIBU 24 MXZ vs MASTERCRAFT X46

WAKE DIMENSIONS

Test PerformedThe surfable wake size was analyzed using the test setup described by Dr. Zalek. The results were verified by ‘push’ measurements from the instrumented rope and by 2D analysis in various positions within the surf zone. The combination of data from these

analyses allowed determination of the dimensions of each wake in terms of length, height and width. These mea-surements were then used to calculate the total wave energy produced by each boat and the total surfable area.

ObservationsIn all 3 boat classes, the Gen 2 equipped boats produced more substantial wakes than that those with Surf Gate. The X46 generated 24% more wave energy than the 24MXZ, the X30 wave energy was 2% more than the 23LSV and the NXT wave energy was 3% more than the Axis 22.

Consumer ConclusionAll 6 boats tested produced long wakes allowing amateur surfers to surf as much as 18 feet back from the boat. The results show that wake length is not a big differentiator between Surf Gate and Gen 2 since all boats product surfable length within 2 feet of one another. On the other hand the push coming from the height and width of

the wakes gave the advantage to Gen 2 in all 3 boat size classes.

FUEL EFFICIENCY

Objective of test In the fuel consumption series of test we wanted to know which of the 2 systems, the Surf Gate system from Malibu or the Gen 2 system from Mastercraft was the more fuel efficient.

Test PerformedFuel flow rate was measured real time using a Diacom PC based diagnostic system. The fuel consumption rates shown were recorded at surf speed with the surf system deployed and with the manufacturers recommended ballast. All tests were conducted multiple times to ensure accuracy and repeatability.

ObservationsThe impact on fuel consumption resulting from deployment of the surf systems was quite different when comparing the 2 systems. The MasterCraft Gen 2 system actually caused fuel consumption to decrease by approximately 10% when the system was deployed at surf speed. In contrast the Surf Gate system deployment (tabs and wedge) resulted in an increase to fuel consumption.

Consumer ConclusionBased on the results above and assuming 100 hours of surfing per year and gas price of $3.50 per gallon the comparison looks as follows:

• The Axis 22 consumes 7% more fuel than the Mastercraft NXT i.e. $236 more annually

• The Malibu 23 LSV consumes 67% more fuel than the Mastercraft X30 i.e. $2625 more annually

• The Malibu 24 MXZ consumes 66% more fuel than the Mastercraft X46 i.e. $2117 more annually

ENGINE RPM

Objective of testEngine speed contributes to fuel consumption, noise level and wear and tear on the engine. Therefore, this series of tests was designed to determine engine speed of each boat when surfing.

Test PerformedThe number of revolutions per minute (RPM) at which the engine crankshaft turns was measured using a Diacom PC based diagnostic system. The engine speeds shown were recorded at surf speed with the surf system deployed and with the manufacturers recommended ballast. All tests were conducted multiple times to ensure accuracy and repeatability.

ObservationsThe engine speeds followed the same pattern as the fuel consumption. That is, the boats equipped with the Surf Gate all needed higher crankshaft rotation speeds to maintain surf speed compared to the Gen 2 equipped benchmark boats.

Consumer ConclusionWithin each size class, the boats with higher engine speeds were less fuel efficient and noisier inside than their comparators.

• Mastercraft NXT operated at 6% lower engine speed than the Axis 22

• Mastercraft X30 operated at 15% lower engine speed than the Malibu 23 LSV

• Mastercraft X46 operated at 15% lower engine speed that the Malibu 24 MXZ

AIR QUALITY – CARBON MONOXIDE LEVELS

Objective of testTo determine carbon monoxide levels in and behind the boat while in surfing mode.

Test PerformedCarbon monoxide gas was monitored using a VRAE Model PGM-7800 Series providing real time ex-posure levels at the 3 sampling locations. Measure-ments were taken at the driver’s seat, aft seat and 3 feet aft of the transom. Also, the boats travelled at surf speed with the surf system deployed and the manufacturers recommended ballast. Test runs were made into and away from the pre-vailing wind direction and averaged.

Observations All boats measured 0 parts per million (PPM) at the driver’s seat and so these readings are not tabulated. In the rear seat location there was no measured accumulation of CO in the Mastercraft boats. The Malibu boats however had measured accumulations averaging more than 50 PPM. Measurements taken 3 feet aft of the transom produced the high-est readings for all boats with the Malibu boats averaging 343 PPM and the Mastercraft boats averaging 42 PPM.

Consumer ConclusionWith surf systems deployed and averaging measurements from the 3 sampling zones:

• Mastercraft NXT operated at an average of 6 PPM compared to an average of 140 on Axis 22• Mastercraft X30 operated at an average of 70 PPM compared to an average of 285 on Malibu 23LSV• Mastercraft X46 operated at an average of 33 PPM comparted to an average of 221 on the Malibu 24 MXZ

NOISE LEVEL IN AND BEHIND THE BOATS

Objective of testTo determine sound levels in and behind the boat during surfing.

Test PerformedSound measurements were taken at the 3 chart-ed locations using an Extech SDL600 sound level meter at surf speed with the surf system deployed and with the manufacturers recom-mended ballast. All tests were conducted mul-tiple times, into and with the prevailing wind and results averaged for each boat.

ObservationsAll boats had comfortably low sound levels at the driver and rear seat zones. In these locations the measurements for the Gen 2 equipped Mastercraft boats were between 1 to 3 dB lower than the Surf Gate equipped boats. As expected, all boats had higher noise reading immediately behind the boats with the NXT quieter that the Axis 22 and the Malibu 23LSV and 24MXZ quieter than their respective Gen 2 equipped Mastercraft boats.

Consumer ConclusionThe Mastercraft NXT was quieter than the Axis 22 in all 3 sound measurement zones. The other 2 Mastercraft boats were quieter inside and noisier outside than their respective Malibu benchmarks.

• Mastercraft NXT operated at an average of 3Db lower noise level that the Axis 22

• Mastercraft X30 operated at an average of 1.33 Db lower noise level than the Malibu 23 LSV

• Mastercraft X46 operated at an average of 1.33 Db lower noise level than the Malibu 24 MXZ

STEERING HANDLING WHEN USINGSURF SYSTEM

Objective of testTo measure which surf system performs best with respect to steering handling.

Test PerformedThis test was to determine how much steering wheel correction (angle and force) was needed to keep the boat heading straight ahead as the surf system was deployed. With the boat trav-elling at surf speed with recommended ballast, the steering wheel was marked for the straight ahead position. The surf system was then deployed causing each boat to veer off course. The amount of steering wheel rotation needed to correct this heading change was mea-sured using an adjustable protractor and the amount of steering wheel force needed to make this correction was also recorded. Force was measured tangentially at the steering wheel spokes using Shimpo FGV-500HX force gauge. All tests were conducted for surf left and surf right and multiple times to ensure accuracy and repeatability.

Observations The boats with Surf Gate required greater steering wheel angle rotation in all 3 boat size classes. In 5 of the 6 boats tested, the steering wheel effort needed to correct the heading change was relatively effortless 3lbs or less. The outlier in the force testing was the Malibu 23LSV that required 14lbs to bring the boat back on course.

Consumer ConclusionIn terms of perceived effort the wheel rotation force is judged to be more important than the actual angle of wheel rotation. Consequently the force required to counteract the Surf Gate deployment on the Malibu 23LSV is a negative, particularly for ≤ 50 percentile adults.

Consumer ConclusionAll 6 boats were in an accept-able range. The NXT had the highest reading (6.2 degrees) but the roll was not noticed by the riders and did not adversely affect handling of the boats.

Test Performed The amount that each boat rolled as a result of surf system deployment was measured using a microprocessor driven data acquisition system utilizing a 12 Bit 3-axis acceler-ometer and a 16 Bit 3-axis gyroscope with a resolution of 0.1 degrees. Redundant measurements were also taken using a Pro 360 digital inclinometer. All tests were conducted multiple times to ensure accuracy and repeatability.

ROLL WHEN USING THE SURF SYSTEM

Objective of testTo measure the amount each boat rotates about its longitudinal axis as a result of surf system deployment.

Observations All 6 boats rolled less when surfing left than surfing right. Surfing left, the 2 surf sys-tems were comparable with maximum recorded roll of 2.4 degrees. Surfing right the Surf Gate equipped Malibu’s rolled less in each boat class averaging 3.2 degrees com-pared to average 5.4 degrees for the Gen 2 systems.

PITCH WHEN USING SURF SYSTEM

Objective of testTo determine how much the bow rises in relation to the stern as a result of surf system deployment.

Test PerformedA zero datum was established with the boat not moving but bal-lasted for surfing. Then the amount that each boat pitched bow up as a result of accelerating to surf speed was measured using a mi-croprocessor driven data acquisition system utilizing a 12 Bit 3-axis accelerometer and a 16 Bit 3-axis gyroscope with a resolution of 0.1 degrees. Redundant measurements were also taken using a Pro 360 digital inclinometer. All tests were conducted multiple times and holding steady at surf speed to ensure accuracy and repeatability.

ObservationsBoth 20 foot boats exhibited more bow rise than the longer boats with the Axis pitching 11.8 degrees compared to 11.6 for the Mas-tercraft NXT. The 23 foot boats exhibited identical pitch at 10.2 de-grees and the Mastercraft X46 had the lowest reading of 7.7 degrees.

Consumer ConclusionThe bow rise that resulted from acceleration to surf speed was within 2 degrees on 5 out of 6 of the boats. The Mastercraft X46 rode considerably flatter at 7.7 degrees of pitch. Forward vision was accommodated with the use of bolster seats on 5 out 6 of the boats. The Axis 22 test boat however did not have a bolster seat and so the driver had to stand in order to get a clear view forward.

TIME TO SWITCH SURF SIDE

Objective of testThis test procedure determined how long it took to switch the surf from one side to the other.

Test PerformedUsing the yaw pitch and roll traces previously recorded by the data acquisition system, we were able to see the time it took to move from a stable roll left to stable roll right condition and vice versa. Since judgment of the precise point of stable roll is somewhat subjective these reading were averaged with times taken from analysis of the video footage.

ObservationsTime to switch does not appear to be a differentiator when comparing Surf Gate and Gen 2 performance since both systems can reposition the wake for opposite side surfing in between 4.4 and 6.3 seconds.

Consumer ConclusionThe ability to be able to switch both these surf systems in 6.3 seconds or less is very convenient when switch-ing riders. The fast switching on all the boats tested means that for ad-vanced surfers, it is feasible to trans-fer from one side of the wave to the other as the switch takes place.

COMPARING USER INTERFACE

The 23 and 24 foot class comparison resulted in very similar number of steps. The surf control systems for all 4 of these boats were easy to comprehend and operate. The major difference in ease of use was in the 20 foot comparison between the Axis 22 and the Mastercraft NXT with the list steps and issues noted below.

STEPS REQUIRED TO SURF• Fill ballast tanks using toggle

switches. Note switches are clearly labeled but have no back lighting. Also, these controls are partly obscured by the right side of the steering wheel and so head and torso movement is required to see them.

• Move away from dock.• Stop engine• Move onto swim platform and open

access door• Reach through access door to release

the wedge spring loaded pins. Note that this is a blind operation.

• Close access door• Restart engine• Set speed using the display and hard

buttons (cruise on)• Use horizontal 3 position toggle

switch to surf side left or right. Note switch is clearly marked but not backlit

• To switch surf side operated surf toggle switch in the opposite direction

• Remember to stow the wedge after use again with the engine off.

STEPS REQUIRED TO SURF• Fill ballast tanks using rocker

switches. • From the home screen press

button under cruise and this displays set speed, wake shaping position and center plate position.

• Select preset profile.• Start surfing• If manual setting are desired then

set speed can be adjusted on cruise screen and trim adjustments on trim screen.

AXIS A22 Surf Gate Mastercraft NXT Gen 2

Comparing Surfing User Interfaces

Mastercraft surf display screens

Slide finger up to adjust

setting

Slide finger down to adjust setting

Malibu surf display screens

SUMMARY OF RESULTS

Benchmark Study Comparing Performance of Wake Surf Systems

This chart summarizes how the Mastercraft Gen 2 and the Malibu Surf Gate systems stack up relative to one another in each of the boat size categories. The comprehensiveness of the study and the range of performance measurements accumulated over several days of testing should be sufficient to answer all questions consumers may have relative to the performance of these systems.

Axis A22

Mastercr

aft NXT

Malibu 23 LS

V

Mastercr

aft X30

Malibu 24 M

XZ

Mastercr

aft X46

₌ ₌ ₌ ₌ ₌ ₌ ₌ ₌1 11 3 8 3 9

AT S

URF

SPEE

D AN

D W

ITH

SURF

SY

STEM

DEP

LOYE

D

SURFABLE AREATOTAL WAVE ENERGY

TIME TO TRANSFER SURF SIDEFUEL CONSUMPTION

ENGINE RPM CARBON MONOXIDE

NOISE LEVEL INSIDE BOATNOISE LEVEL BEHIND BOAT

STEERING HANDLINGROLL ( surf right)

ROLL ( surf left)

20 FOOT 23 FOOT 24 F00T

PITCHHUMAN FACTORS

TOTAL SCORE

This chart summarizes how the Mastercraft Gen 2 and the Malibu Surf Gate systems stack up relative to one another in each of the boat size categories. The comprehensive-ness of the study and the range of performance measurements accumulated over several days of testing should be sufficient to answer all questions consumers may have rela-tive to the performance of these systems.

1 Footnote: Refer to ABYC TH-23 for dangers associated with extended exposure in excess of 125 PPM.

ADDENDUM: TEST DATA

1