Poseidon DPS

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

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 Janak Dave, PhD, Thesis Advisor Accepted by , l'~w(f,l£~~ 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.

ii 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

iii 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

iv 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

v 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.

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.

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.

Single Double Single Parallel Parallel Battery Concentric

Figure 2 – DPS Configurations

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.

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.

Waterline Hull Draft

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-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

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 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

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 16

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

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 18

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.

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.

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.

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?

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]

Gilbert Lanham 625 Lindemann Lane Mason OH 45040 23

Appendix B – Survey Responses

Appendix C – Quality Functional Deployment

Appendix D – Calculations

Housing Calculations

6061-T4 Aluminum Yield Strength = 21,000 170 ft. depth = 6 atmospheres = 88 psi

P * R σ = T

Large Housing:

Radius = 4.5 in.

88* 4.5in 21,000 = Min. Thickness = .0189 in. t

Medium Housing

Radius = 3.5 in.

88*3.5in 21,000 = Min. Thickness = .0146 in. t

Small Housing

Radius = 1.75 in.

88*1.75in 21,000 = Min. Thickness = .0073 in. t

Shaft Calculations

6061-T4 Aluminum Shear Strength = 24,000 psi Safety Factor = 3 Shaft Hp = .25 RPM = 1800

321,000* SHP * SF D = 3 St * RPM 26

321,000*.25*3 d = 3 Minimum Diameter = .177 in. 24,000*1800

Horsepower Requirements

Speed = 2.4 Knots = 2.77 mph Waterline Length = 6.5 ft. Weight of Diver and Equipment = 350 lb

Kts 2.4 SL _ Ratio = SL _ Ratio = SL Ratio = .94136 WL 6.5

10.665 10.665 SL _ Ratio = .94136 = lb/SHP = 1454.16 3 lb / SHP 3 lb / SHP

350lb HP = .2407 1454lb / SHP

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

Disp 350lbs C = C = Blocking Ratio = .280 b WL * BWL * Hd *64lbs / ft 3 b 6.5* 2*1.5*64

W f = 1.11− (.6*Cb ) W f = 1.11− (.6*.280) Wake Factor = .942

.5 .5 Dmin = 4.07 *(BWL * Hd) Dmin = 4.07 *(2*1.5) Minimum Diameter = 7.049 in.

632.7 * SHP.2 632.7 *.25.2 D = 7 = Revolutions Per Minute = 1146 RPM RPM .6 RPM .6

Va = Kts *W f Va = 2.4*.942 Speed of Advance Through Wake = 2.26 Knots

SHP.5 * RPM .25.5 *1500 = = B p 2.5 B p 2.5 Bp = 97.67 Va 2.26

RPM * D 1500*7 δ = δ = δ = 387.17 12*Va 12* 2.26

From Graph 6.4:

Pitch Ratio = 5

7 in. * .5 = 3.5 pitch

ή = 43.5

326* SHP *η 326*.25* 43.5 T = T = Thrust = 15.68 lbs Va 2.26

Appendix E – Wiring Diagrams

555 Trigger Vcc

555 Pulse Width Modulation

Vcc

IRF 1302 Switching Circuit

Appendix F – Part Drawings

Appendix G – Purchased Components

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