Poseidon DPS
by
GILBERT E. LANHAM
Submitted to the MECHANICAL ENGINEERING TECHNOLOGY DEPARTMENT
In Partial Fulfillment of the Requirements for the
Degree of
Bachelor of Science In
MECHANICAL ENGINEERING TECHNOLOGY
at the
OMI College of Applied Science University of Cincinnati
June 2005
© ...... Gilbert E. Lanham
The author hereby grants to the Mechanical Engineering Technology Department permission to reproduce and distribute copies of the thesis document in whole or in part.
Signature of Author
Certified by
Accepted by
Janak Dave, PhD, Thesis Advisor
, l'~w(f,l£~~
ii
Abstract
Diving Propulsion Systems are a useful tool for a broad range of SCUBA divers
since they allow divers to cover a larger area during a dive and conserve air through less
exertion. The typical hand-held DPS can be cumbersome for divers that participate in
two-handed activities like photography, underwater welding and spearfishing. Only one
diving propulsion system, the Aquanaut SPU, satisfies the needs of divers who must have
their hands free. The Poseidon DPS will improve upon current designs while being a
hands-free diving propulsion system.
From research, a slim profile, one hour battery life, variable control, and
manufacturing cost under $950 are all product features that are required by divers. The
characteristics were kept in mind when designing the Poseidon DPS. A “torpedo” style
housing was designed that attaches to the bottom of the air tank. The DPS was fabricated
from standard materials and components using standard machine tools.
The Poseidon DPS was initially tested for functionality in a swimming pool. The
circuitry for the variable speed control was not completed, but the speed, maneuverability
and functionality of the DPS was outstanding. The battery life lasted 67 minutes which is
well above the average dive duration. The Poseidon DPS was a success and with
refinements could potentially sell well in the marketplace.
iii
Table of Contents Introduction ………………………………..……..……………………………..... 1 Need for a Superior DPS ………….…..………..………………………. 1 Diver’s Requirements ………..….………………………………..……. 2
Desired Requirements …........................................................................ 4 Relative Importance of Engineering Characteristics …………………… 5 Measurable Product Features ………… ……………………………….. 6
Design Solution .….……………………………………...……………………… 7 DPS Configuration Selection ...….………………………………………. 7 Horsepower Requirements ………………………………………………. 9 Propeller Calculations …………………………………………………… 9 Shaft Calculations. …………………………..………………………….. 10 Housing Calculations …..………………………………………………. 10 Electrical Design ………………………………………………………… 11
Miscellaneous Design …………………………………………………… 12 Assembly Design ………………………………………………………... 12
DPS Fabrication ….. ………. …………………………………………………… 14 Housing Fabrication …………………………………………….……….. 14 Miscellaneous Fabrication ………………………………………………. 14 Electronic Fabrication …………………………………………………... 15 DPS Assembly ………………………………………………………….. 15 DPS Testing ……………………………………………………………………. 17
iv
Conclusion and Recommendations ..…………………….……………………… 19 References …………………………………………………………….………… 20 Appendix A Survey ………………….............……………………………………………….. 21 Appendix B Survey Responses …………………………………………….…………….…. 23 Appendix C Quality Functional Deployment …………..……………………………………. 24 Appendix D Calculations …………………………………………………………………….. 25 Appendix E Wiring Diagrams ……………………………………………………………….. 28 Appendix F Part Drawings …………………………………………………………………. 30 Appendix G Purchased Components ……………………………………………..…………… 46 Appendix H Proof of Design ………………………………………………………….………. 54 Appendix I Bill of Material …………………………………………………………………. 55
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List of Figures Figure 1 Aquanaut SPU…..……………………………………………………………… 2 Figure 2 DPS Configurations..…………………………………………………………… 7 Figure 3 Weighting Tree .………………………………………………………………… 8 Figure 4 Weighted Decision Matrix ...………………………………………………….... 8 Figure 5 Hull Characteristics………………..…………………………………………… 9 Figure 6 Assembly View……………………………………………..…………………… 13 Figure 7 Exploded View.………………………………………….……………………… 13 Figure 8 Poseidon DPS...………………………………………………………………… 16
1
Introduction Need for a superior DPS
Diving Propulsion Systems are a useful tool for a broad range of SCUBA divers.
Diving Propulsion Systems allow divers to cover a larger area during a dive and conserve
air through less exertion. However, the typical hand-held DPS can be cumbersome for
divers that participate in two-handed activities like photography, underwater welding and
spearfishing. A limited number of diving propulsion systems satisfy the needs of divers
who must have their hands free. The Poseidon DPS will allow a diver’s hands to be free
while providing propulsion needs.
The current design for a hands-free DPS, the Aquanaut SPU manufactured by
Aquadyn Underwater Technologies, has a top speed of three mph with a battery life of
thirty minutes [1,2]. The battery life is not long enough to last for the typical dive of 62
minutes [Appendix B, Survey Responses] and needs to be recharged in-between each
dive. This is extremely impractical when multiple dives are made throughout the day,
which is common. The current design only has two speed settings. Ideally, a control
device would have either a variable control, or several speed settings. A slim profile is
important to many divers and is essential to some. Cave divers in particular must move
through tight spaces. The Aquanaut SPU is bulky and does not satisfy this need.
Increasing the battery life, adding flexibility in speed control, streamlining the profile,
and reducing the cost will make a more desirable diving propulsion device.
2
Figure 1 – Aquanaut SPU
In general, the people most interested in a diving propulsion system are
experienced divers, with an emphasis on “technical divers.” A hands-free DPS is
particularly appealing to divers with disabilities and divers that have a specific task to
complete. This product would be very helpful to underwater photographers, underwater
welders, salvagers, spear fishermen, and divers paralyzed from below the waist.
With my experience, the most frequent buyers of diving propulsion systems are
cave divers. Cave divers tend to dive deeper and stay down for a longer time. It is
important for them to conserve air. The less energy a cave diver has to exert, the more air
the diver can conserve and the longer he or she can stay down. It is essential for cave
divers to maintain a slim profile. There are many times that they must squeeze through
tight spots and a slim profile is critical. A slim profile, hands-free DPS will also appeal
to cave divers when a diver is actually in a cave because he or she will not have to drag a
hand held DPS along.
Diver’s Requirements The design of the Poseidon DPS addresses the deficiencies of the Aquanaut SPU
as well as other diving propulsion systems. All diving propulsion systems except for one
3
require to be held by both hands. The most common configuration resembles a torpedo
and drags the diver through the water. This makes photography, welding, spear-fishing,
salvaging, and cave diving more difficult since the diver has to contend with the DPS in
order to complete the other tasks. Fourteen responses were received from the survey in
Appendix A. A hands-free DPS will eliminate the time and frustration involved with
juggling devices and is the second most important factor according to the survey
responses located in Appendix B. The Poseidon DPV will attach to the air tank and be
controlled by a device attached to the belt or forearm. This will make the Poseidon DPV
completely hands-free except when adjusting the speed of the DPV.
The Aquanaut SPU’s battery life is thirty minutes when operating at the
maximum speed. Proper battery and motor selection will enable the Poseidon DPS to
operate for over one hour at the top speed. In order to accomplish this, the DPS may
require more than one battery, but according to the survey responses in Appendix B,
battery life is the most important factor in a DPS.
A slim profile is one of the most important factors for cave divers according to a
personal correspondence with Jeff Lanman at Scuba Unlimited [2]. Respondents agreed
that this was important. A slim profile was the third most important factor reflected in the
survey responses in Appendix B. The Aquanaut SPU’s motor and propeller assembly
extends above the air tank creating a poorly streamlined profile. Jeff Lanman said that
being a cave diver, he would not purchase the Aquanaut SPU due to the exteme
protrusion and he guessed that many other cave divers would do the same. Therefore it is
important for the Poseidon DPS to have as streamlined of a profile as possible. There are
several possibilities of accomplishing this. The more likely configurations for the
4
Poseidon DPS include motor and propeller assemblies located concentrically with the air
tank or adjacent to the air tank on the lower back.
The Auquanaut SPU has only two speed controls. This doesn’t offer many options
on how fast a diver can travel when using the DPS. Some hand-held diving propulsion
vehicles, like the Oceanic Mako, offer a variable speed control and I believe this will be
an excellent nice feature for the Poseidon DPS. According to the survey responses in
Appendix B, this feature is not as important as others, but I believe that it is a nice selling
point.
Since cost is always an issue, the Poseidon DPV is projected to cost less than
$900 to manufacture. The aquanaut SPU’s retail price is $1399. Many hand-held diving
propulsion systems cost more than $2500. Submerge Inc.’s most inexpensive model, the
UV-18,has a cost of $3600. One person listed on his survey that he paid $4000 for the
DPS that he currently owns! Many people did list cost as an important factor. The quality
and function of equipment is extremely important to cave divers and cost is really not an
issue to them. Therefore the final design will have to be a compromise between the best
possible product and keeping the manufacturing cost below $950.
Desired Requirements
Fourteen survey respondantaranked product features in order of importance (see
Appendix B, Survey Responses). Battery life was the most important feature according
since they reported an average time spent underwater was 62 minutes. This seems on the
high end, but by designing the Poseidon DPS to last one hour, the customer should be
satisfied. A hands-free design was ranked as the second most important feature. This is
5
especially useful since seven cave divers, six photographers and two salvagers responded
to the survey. The survey responses make a direct correlation between the importance of
a hands-free design and divers that participate in these activities. Maximum depth was
identified as the third most important concern, and according to the survey responses, the
average depth of a typical dive is 86 feet. Therefore, the customer should be happy with a
maximum depth rating of 170 feet, since it is more than twice the average depth of 86
feet. Responses show that the customers are willing to pay $1375 for the Poseidon DPS.
If the DPS can be manufactured for under $950, there will be more than a thirty percent
markup making the product profitable. The top speed and speed control were rated
approximately the same. Eleven out of fourteen surveys listed a variable control as the
preferred means of speed control. The Poseidon DPS will incorporate a pulse-width
modulation circuit to allow the motor to have a variable control.
Relative Importance of Engineering Characteristics
The quality functional deployment shows relationships between product features
and engineering characteristics. The product features used in the QFD were battery life,
speed, depth rating, cost, slim profile and hands-free design. The engineering
characteristics that affect the product features are battery selection, propeller selection,
motor selection, housing design, seal design, electronic design and overall configuration.
As the QFD Shows, the overall configuration is the most important engineering
characteristic, followed by electronic design, housing design, motor selection, battery
selection, seal design and propeller selection [see Appendix C, Quality Functional
Deployment].
6
Measurable Product Features
In order to measure the effectiveness of the Poseidon DPS, benchmarks were
established to quantitatively measure the performance of the product. During testing the
Poseidon DPS should meet the following objectives:
1. The battery life of the device must last at least one hour operating at its top speed.
2. The variable speed control must move the motor speed through a full range of rpms. It must begin at zero rpm, or a specified minimum value, and move without hesitation to a maximum operating speed specified by the designer. 3. The device must have minimal protrusions around the bird’s-eye view profile of the diver or equipment not exceeding 8 inches. 4. The total manufacturing cost must be less than $950.
7
Design Solution
DPS Configuration Selection
A weighted decision matrix was used to choose between three different
configurations for the Poseidon DPS. The three configurations considered are the single
parallel battery, single concentric and the double parallel shown in Figure 1. The smaller
squares represent batteries and the larger squares represent the motor/propeller assembly.
Manufacturing and feature characteristics were broken down into a “weighting tree”,
Figure 2, to assign numerical values to the importance of material cost, manufacturing
cost, labor cost, weight, configuration and slim profile. These factors are then used in a
matrix format, shown in Figure 3, to determine which design alternative is best.
Figure 2 – DPS Configurations
Single Parallel Battery
Single Concentric
Double Parallel
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Figure 3 – Weighting Tree
Figure 4 – Weighted Decision Matrix
The weighted decision matrix shows that the single concentric configuration is
best. It has the best balance between cost and features. The double concentric
configuration would be ideal, but impractical due to the scope of this project and fact that
the number of components would be double. The single parallel baterry configuration is
not a good as the single concentric configuration because material costs would be higher
and there would have to be separate housings for the batteries. Therefore the single
concentric configuration is the best.
9
Hull Draft
Waterline
Horsepower Requirements
The Propeller Handbook [4] was used for the horsepower calculations. The
equations took into account the desired speed, weight of the diver and the waterline
length. Waterline length is the two dimensional length of where the hull sits in the water,
see Figure 4. I made an assumption that the overall length of the average diver is the
waterline length required for the DPS. The calculations shown in Appendix D require that
the DPS must have ¼ horsepower to make the dive travel at 2.75 mph. A Leeson 108045
¼ HP electric motor will be used, Appendix G.
Figure 5 – Hull Characteristics
Propeller Calculations
The propeller calculations take into account several factors including the
waterline length, beam length, hull draft, maximum speed, weight of the diver and the
power of the motor. Several ratios and factors were calculated in Appendix D. The
10
important calculated characteristics are minimum diameter, seven inches, and optimum
revolutions per minute, 1146. The pitch of the propeller, length of advance every turn,
was calculated. This is only a ballpark figure since the Propeller handbook didn’t have
Bp
The rated depth of the DPS will be 170 feet. The water pressure at this depth is 6
atmospheres or 88 psi. Using the equation found in Mechanics of Materials [5], the hoop
stress was calculated for the round housing that will contain the DPS’s components. 6061
-δ graphs for the size of propeller the DPS will require. A seven inch propeller is
nearly impossible to find and the only company that seems to make them is the Michigan
Wheel Company. Since it is a custom order, the propeller would cost upwards of $400.
Delta Propeller located in Cleves Ohio had a polymer propeller and the charged a grand
total of ten dollars. It is a seven inch by four pitch propeller, which will suit the needs of
the DPS.
Shaft Calculations
An equation used from the Propeller Handbook [4] was used to calculate the
minimum diameter of the propeller shaft. The electric motor has a maximum speed of
1800 revolutions per minute and as a worst case scenario, I used this for the revolutions
per minute in the equation. Horsepower, safety factor and shear strength was also used.
The shaft will be made from 6061 aluminum and the shear strength is 24,000 psi. The
calculations show that the minimum diameter of the shaft is .177 inches, Appendix D.
Since the propeller must sit on a ½ inch shaft, failure of the shaft should not be an issue.
Housing Calculations
11
aluminum will be used to for the housing and the equation calculates the minimum wall
thickness of a cylinder. A series of three round housings will be used and the largest
minimum thickness is .0189 inches, Appendix D. Since the wall thickness of the housings
will be ½ inch, the housing should not fail.
Electrical Design
The Leeson 108045 electric motor draws a maximum of 21 amps. Therefore the
amp-hour capacity of the batteries must be equivalent to 21 amps. Two EP17-12 batteries
manufactured by B & B Battery will be used. The product specifications do not call out a
one hour amp-hour capacity, but from a consultation with an engineer at B & B battery
[6], two EP17-12 batteries will work.
In order for the electric motor to have a variable control, a technique called pulse
width modulation will be employed. When using PWM, the motor is not run on a
constant voltage. The PWM controller sends pulses to the motor and when the duration of
the pulses is varied, the speed of the motor change. The design that will be used will have
a dial potentiometer that will control the PWM signal generator. By turning the dial, the
speed of the motor will change. I sought the help of Mr. Andrew Boniface [7] to help
design the electronics. The circuit in Appendix E consists of two 555 Integrated chips and
a IRF 1302 integrated chip. A 555 chip is essentially a timer and in order for it to operate,
it must be triggered with voltage. The first 555 circuit is a trigger for the second. Since
pin number to is connected directly to the voltage source, it is constantly being triggered.
The second 555 circuit is what sends the pulse width modulation signal to the switching
circuit. The modulation input is a 1 kilo ohm potentiometer and the output is sent the
12
switching circuit. The switching circuit consists of an IRF 1302 switching circuit which
can handle very high currents. It also has the battery as a power source, an induction coil
and capacitor to store voltage while the pulses are “off”. This circuit enables the user to
control the device’s speed through a full range without hesitation.
Miscellaneous Design
The shaft seal is manufactured by Chicago Rawhide. The part number is CR4991
and it is a small bore long life fluroelastomer seal. It fits onto a ½ inch shaft and has an
outside diameter of .999 inch. The seal has a maximum pressure rating of 90 psi. This
will be the limiting factor on the depth of the DPS. This component will be press fitted
into the “front Plate” of the assembly.
The gasket for the assembly will be manufactured by quick cut. IT will be a
neoprene gasket 1/16 in. thick. It will be sealed with a polymer based plyobond contact
cement. The gasket will have 8 3/16 holes for bolts to fasten the back plate to the battery
housing. According to a correspondence with an engineer at Quick Cut [8], this gasket
will definitely work at 90 psi.
Assembly Design
The final assembly is shown in Figure 5. It consists of three round housings, with
four plates. The front three plates are welded to the housing and the backplate is bolted
onto the battery housing. The electric motor is bolted onto the middle plate and sealed
with the polymer based contact sealer. The propeller shaft will be press fitted onto the
motor shaft. The propeller will sit on a pin inserted through the propeller shaft and be
13
tightened by a nut on the end of the propeller shaft. The exploded view of the assembly is
in Figure 6.
Figure 6 – Assembly View
Figure 7 – Exploded View
14
DPS Fabrication
Housing Fabrication
The housing material consisted of 6061 aluminum tubing and sheet metal
listed in the bill of materials located in Appendix I. For the round end plates of the
housing, the sheet metal was roughly cut with a plasma cutter followed by a closer cut
with a table band saw. The final diameters of the end plates were turned on a lathe. The
counterbore in the front plate was turned on the lathe. The tubing was cut to length with
an automatic band saw. All plates and tubing were TIG welded to produce the housing.
The front plate, front housing and middle plate were welded together first so that the
motor could be fitted and the motor’s bolt holes could be drilled with a drill press. Then
the front assembly was welded to the middle housing, center plate and the battery
housing respectively. Eight bolt holes were drilled and tapped on the battery housing, and
eight bolt holes were drilled on the back plate using a drill press and hand tap. Two 3/8
NPT pipe threaded holes were drilled into the battery housing for battery recharging and
the potentiometer hose. Lastly the tank boot and two strap supports were welded to the
back plate
Miscellaneous Fabrication
The propeller shaft was turned on a lathe. All outside and inside diameters of
the housing plates were turned from 6061 aluminum bar stock. The keyway on the inside
diameter was shaved on the lathe with a sharpened piece of square tool steel. The cross
hole and setscrew hole were drilled on a drill press.
15
The potentiometer housing and potentiometer cap were turned on a lathe.
The 3//8 NPT pipe thread and bolt holes were drilled on a drill press and tapped with a
hand tap.
Electronic Fabrication
The electronics were initially assembled into a breadboard according to the
wiring diagram. This was to test for the functionality of the circuit on an oscilloscope.
The pulse width modulation waveform was confirmed on the oscilloscope, but there was
a small voltage spike at the top of each waveform, which did not seem to be an issue at
the time. The circuit was then soldered together on a circuit board. When the circuit was
connected to the electric motor and batteries, the circuit ran properly for about 15
seconds. Then IRF 1302 chip began to smoke and the batteries were disconnected. The
small voltage spike was enough to burn out the chip which was only rated for 12V. The
IRF 1302 was replaced with an On Semiconductor NTP45N06 chip. When the new
circuit was tested, the NTP45N06 chip failed. This could be due to static electricity or a
short that was created on the timing circuit somewhere in between the original test and
when the circuit was updated. Due to time constraints, a relay was wired into the circuit,
which meant that the motor would only turn on and off.
DPS Assembly
The shat seals were press-fitted into the front plate and Potentiometer cap.
The propeller shaft was placed onto the motor shaft, and the set screw was tightened. The
motor was then placed into the housing, and bolts were inserted to hold the motor to the
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housing. The electronic relay control was connected and placed into the housing. The
potentiometer was placed in the potentiometer housing and its wires were run through the
potentiometer hose to the main housing. Once the electronics were fully assembled, the
batteries were attached to each other with two nylon straps and placed in the housing. To
finish assembly, gasket sealer was used to attach the gasket to the housing. Finally the
back plate was bolted on. The final product is pictured in Figure 8.
Figure 8 – Poseidon DPS
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DPS Testing
In order to test the Poseidon DPS a trail run in a swimming pool was
required. The functionality and variable speed control can be tested in a swimming pool.
To test the battery life, the DPS was put into a bathtub, held stationary and was tuned on
until the battery power was depleted. The protrusions were measured with a tape
measurer and the total cost was added up after expenditures.
The trial run in the pool went great, except for the fact that the variable speed
control was not functioning. The DPS was operated for about 15 minutes and ran very
well. The electric motor provided more than enough power for propulsion needs. The
actual speed was not measured, but the DPS propelled the diver significantly faster than
the swimmers in the pool. Maneuverability was easily managed by angling the body/DPS
in the direction desired. Although the DPS is heavy out of water, it was only slightly
negatively buoyant when in the water and could be held with one hand.
The battery life test went better than expected. The battery life lasted over 67
minutes at the highest speed setting. This is above the average dive duration. In most
situations a DPS would not be used continuously at the maximum speed and if the battery
power was used conservatively, the Poseidon DPS could definitely last for two dives.
The maximum protrusion from the diver’s equipment was measured to be 1.5
inches with respect to a bird’s eye view. This will meet the cave diver’s expectations.
The production cost including 15 hours of labor, went over budget by
$345.30 or 36%. It was very difficult to find the aluminum material required and when it
was finally located, the price was very unreasonable. This was due to the fact that it was a
one time order and that it was being sold to a student and not a company. If the Poseidon
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DPS went into production, a 30% material discount over retail pricing is reasonable. If a
30% discount is applied to material costs, the total Production cost of the DPS is $974.21
or 2.5% over the $950 originally budgeted. If the Poseidon DPS was sold at $1300, $100
less than the Aquanaut SPU, the profit margin would be 25%. At first glance this project
did go over budget, but this is also a prototype. The costs of prototypes are always higher
than the costs of production products. If the Poseidon DPS were to go into production,
the material costs would be significantly lower meeting the projected budget.
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Conclusion and Recommendations The Poseidon DPS would definitely see improvements if it went into
production. Custom batteries would be very helpful. If a battery could be produced with a
smaller profile and longer length, the diameter of the housing could be reduced.
Producing a casting for the main housing would nearly eliminate the labor costs
associated with manufacturing the housing from sheet metal and tube stock. A large
percentage of labor was attributed to producing the main housing and if the housing was
one solid casting labor costs would be greatly reduced. Fluid dynamic curves could be
incorporated into the design if a casting was produced. The casting would be curved to
promote water flow over the housing. A curved housing would increase the speed and
efficiency of the Poseidon DPS. With respect to producing this prototype, the design and
fabrication of the electronics should have been outsourced to a company. This would
have saved many hours of work and assured the variable speed control’s functionality.
Aside from these improvements, the Poseidon DPS is a great propulsion
system. It functioned very well and was a pleasure to operate. I am very proud if this
accomplishment. The Poseidon DPS is definitely a product worth going into production.
It offers a unique solution to SCUBA diving propulsion needs. From the interest
displayed in survey responses and the excitement observed during personal
correspondences with SCUBA divers, there is undoubtedly market for a hands-free DPS.
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References
1. “The Ultimate Underwater Propulsion System Aquanaut SPU” Aquadyn Underwater
Technologies, Oct. 2004, http://www.aquadyn.com.
2. H2Odyssey 2005 catalog.
3. Jeff Lanman, Manager, Scuba Unlimited, Personal Correspondence, October –
November 2004.
4. Gerr, David. The Propeller Handbook. Camden: International Marine. 1989.
5. Beer, Fersinand et al. Mechanics of Materials
. New York: McGraw-Hill. 2001.
6. Tony Chein, Engineer, B & B battery, Personal Correspondence, February 23, 2005.
7. Andrew Boniface, Lab Technician, Electrical Engineering Technology Department,
College of Applied Science, University of Cincinnati, Personal Correspondence,
February – June 2005.
8. Engineer, Quick Cut, Personal Correspondence, February 2005.
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Appendix A – Survey
My name is Gilbert Lanham and I am a mechanical engineering student at the University of Cincinnati. I am proposing a hands-free diving propulsion system for my senior design project. I have written this survey in order to aid the product development process and I would appreciate if you would fill it out. Please circle the appropriate answer. For questions with ratings, 5 is the best and 1 is the worst. 1. On average, how long is a typical dive for you? a) 20 min. b) 30 min. c) 40 min. d) 50 min. e) 60 min. f) 70 min. g) 80+ min. 2. How many dives per day do you make? a) 1 b) 2 c) 3 d) 4+ 3. How deep are your typical dives? a) 50 b) 60 c) 70 d) 80 e) 90 f) 100 g) 110 h) 120 i) 130 j)140 k)150 l) 160+ 4. What is the deepest depth that you have gone? ________________ 5. What type of diving do you do? a) recreational b) commercial c) other _______________ 6. If commercial, what industry? __________________________ 7. What are your diving interests? a) photography/video b) wreck diving c) night diving d) search/salvage e) hunting f) nature/biology g) ice diving h) welding/fabrication i) deep diving j) cave/cavern diving l) other ______________ 8. Have you used a diving propulsion system before? a) yes b) no 9. Would owning a DPS interest you? a) yes b) no 10. How important is it for a DPS’s battery to last more than one dive?
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1 2 3 4 5 11. How important is a hands-free DPS to you? 1 2 3 4 5 12. How important is a slim profile? 1 2 3 4 5 13. Are you involved in activities that a hands-free DPS would benefit? a) photography b) welding/fabricating c) salvage/recovery d) hunting e) cave diving f) other ________________ 14. How many speed control settings would you like? a) 1 b) 2 c) 3 d) 4 e) 5 f) 6 g) 7 h) variable speed control 15. What top speed would you consider a high performance DPS to have? a) 1 mph b) 2 mph c) 3 mph d) 4 mph e) 5 mph f) 6 mph 16. What would you be willing to realistically pay for a hand-free DPS? a) $500-$750 b) $750-$1000 c) $1000-$1250 d) $1250-$1500 e) $1500-$2000 17. Please rank in order of importance: (6 = highest 1 = lowest) ___ Battery Life ___ Speed ___Depth Rating ___Speed Settings ___ Cost ___ Slim Profile Additional Comments: (Profile, weight, buoyancy, or features you would like to see) Thank you for filling out this survey. It means a lot to me and it will aid my decision making process. Please send the completed survey and contact information to: [email protected] or Gilbert Lanham 625 Lindemann Lane Mason OH 45040
23
Appendix B – Survey Responses
24
Appendix C – Quality Functional Deployment
25
Appendix D – Calculations
Housing Calculations 6061-T4 Aluminum Yield Strength = 21,000 170 ft. depth = 6 atmospheres = 88 psi
TRP *
=σ
Large Housing: Radius = 4.5 in.
tin5.4*88000,21 = Min. Thickness = .0189 in.
Medium Housing Radius = 3.5 in.
tin5.3*88000,21 = Min. Thickness = .0146 in.
Small Housing Radius = 1.75 in.
tin75.1*88000,21 = Min. Thickness = .0073 in.
Shaft Calculations 6061-T4 Aluminum Shear Strength = 24,000 psi Safety Factor = 3 Shaft Hp = .25 RPM = 1800
3*
**000,321RPMS
SFSHPDt
=
26
31800*000,24
3*25.*000,321=d Minimum Diameter = .177 in.
Horsepower Requirements Speed = 2.4 Knots = 2.77 mph Waterline Length = 6.5 ft. Weight of Diver and Equipment = 350 lb
WLKtsRatioSL =_
5.64.2_ =RatioSL SL Ratio = .94136
3 /665.10_SHPlb
RatioSL = 3 /
665.1094136.SHPlb
= lb/SHP = 1454.16
SHPlblb/1454
350 HP = .2407
Propeller Calculations Speed = 2.4 Knots = 2.77 mph Waterline Length = 6.5 ft. Waterline Beam Length = 2 ft. Hull Draft = 1.5 ft. Weight of Diver and Equipment = 350 lb Motor Power = .25 HP
3/64*** ftlbsHdBWLWLDispCb =
64*5.1*2*5.6350lbsCb = Blocking Ratio = .280
)*6(.11.1 bf CW −= )280.*6(.11.1 −=fW Wake Factor = .942
5.
min )*(*07.4 HdBWLD = 5.min )5.1*2(*07.4=D Minimum Diameter = 7.049 in.
6.
2.*7.632RPM
SHPD = 6.
2.25.*7.6327RPM
= Revolutions Per Minute = 1146 RPM
fa WKtsV *= 942.*4.2=aV Speed of Advance Through Wake = 2.26 Knots
27
5.2
5. *
ap V
RPMSHPB = 5.2
5.
26.21500*25.
=pB Bp
aVDRPM
*12*
=δ
= 97.67
26.2*127*1500
=δ δ = 387.17
From Graph 6.4: Pitch Ratio = 5 7 in. * .5 = 3.5 pitch ή = 43.5
aVSHPT η**326
= 26.2
5.43*25.*326=T Thrust = 15.68 lbs
28
Appendix E – Wiring Diagrams
555 Trigger
555 Pulse Width Modulation
Vcc
Vcc
29
IRF 1302 Switching Circuit
30
Appendix F – Part Drawings
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
Appendix G – Purchased Components
47
48
49
50
51
52
53
54
55
Appendix I - Bill of Materials
Leeson 108045 Motor 258.90 B&B Battery EP17-12 Battery (2) 100.00 Polymer Propeller 10.00 Quick Cut Neoprene Gasket 15.45 Chicago Rawhide 4991 Seal 8.77 1/2-20 nut .50 1/4-20 Bolt (8) 1.50 3/8-16 Bolt (4) 1.00 555 Chip 2.00 IRF 1302 Chip 2.00 .01 μF Capacitor (2) 2.00 .1 μF Capacitor 1.00 .9 kΩ Resistor .50 .1 kΩ Resistor .50 9.1 kΩ Resistor .50 1mH induction Coil 3.00 1 kΩ Potentiometer 2.00 Circuit Board 2.00 Wiring 2.00 Gasket Sealer 5.00 6061-T6 Aluminum: 8” OD .5” Thick 10” OD .5” Thick (2) 4.5” OD .5” Thick 10” OD 9” ID 8” Long 8” OD 7” ID 11” Long 4.5” OD 3.5” OD 1.875 Long 1.125” OD 5” Long .15” OD .9” Long Aluminum Cost: 651.68 Labor Cost (15 hrs. @ $15): 225.00 Total Cost: $1295.30 Cost Difference: $345.30 or 36% With 30% discount on materials: $974.21 or 2.5% over