April Fool's Day could not have been a more appropriate day to set a World Record. Throughout the entire project, completing but one run through the course without vessel damage or personal injury was the overriding goal. This goal was accomplished. Sub-Lime will be listed as having successfully participated in the 1996 World Submarine Invitational, an honor attempted by many and achieved by few. It was beyond my wildest imagination to even consider Sub-Lime as competitive, least of all of record setting caliber. But much to everyone's surprise, Sub-Lime not only was competitive, but set a IHPVA World Record in the process, on this First day of April 1996.

I - Personal Background

II - Project Development
          A - Initial Design Constraints
                    (a) - Technology Availability
                    (b) - Budgeting
          B - Initial Material Handling - Design Modification (#1)
          C - Construction
                    (a) - Pattern Making
                    (b) - Model Testing
                    (c) - Construction

III - Pool Testing
          A - Buoyancy Configuration
          B - Propulsion Testing & a Death Defying Experience
                    (a) - Design Modification (#2)
                    (b) - Hull Repair
          C - Performance Envelope Development (Learning how to Drive)
                    (a) - Design Modification (#3)
                    (b) - Design Modification (#4)

IV - The Race (World Submarine Invitational 1996)
          A. - Five Successful Runs
          B. - Two Unsuccessful Runs

V - Lessons Learned

VI - Thanks

___________________________________________________________________

I - Personal Background

Born         - New York
Education - Primary          - NYC Public Schools
                - College          - Florida Institute of Technology (Under Graduate & Graduate School)
                - Professional   - Marquette University School Of Dentistry
                - Residency      - VA Hospital, Loma Linda, CA
Military    - USMC           - Naval Flight Officer/Electronic Warfare Officer/VMAQ-2
Diving       -Scuba             - Pre-Certification since 1966, Certified 1973
                                          (Scuba Instructor: LA County, NAUI, YMCA)

II - Project Development

     I was inspired while attending the 1994 West Coast Invitational, I went to see my alma mater, Florida Institute of Technology, participate. My wife Jane and I observed the excitement and challenges of Human Powered Submarine Racing in person. What was the most striking observation was how much FUN all the participants were having. Each Submarine team observed had some difficulty, such as crashes or other setbacks, and some didn't even complete the course. But it became intuitively clear to even the most casual observer that just being there as participants was all the reward they needed. For all the time and effort they put into the making of their submarines, their overall results in the competition were irrelevant, as they were having FUN. (And what more can you ask for from submarine races.)

A - Initial Design Constraints

     Having received the Design Guidelines and reading: "... a submarine is a free- flooding (liquid filled) marine vehicle that fully encapsulates the occupants and operates entirely beneath the surface of the water..." I said: "HEY. I CAN MAKE THAT." My wife said in a tone of sarcasm, "Sure honey, go right ahead. (I could tell that she didn't believe me, but I considered her remark a go-ahead.) I love challenges.

(a) - Technology Availability

     Being not only the designer and fabricator, I had the choice from all of the latest technology that money can buy at my disposal...

(b) - Budgeting

     ...Of course I only had 2 Grand at my disposal. It was agreed that the budget allocated to this project will not exceed $2,000.00 (two thousand dollars) to include all Fees, Materials, Tools and Equipment. This project was after all, a form of adult entertainment, and not an obsession.

B - Initial Material Handling

     The original design called for a compound curved acrylic skin over a rigid frame. Initial experiments to establish expertise and proficiency in materials handling resulted in a number of art deco "fruit bowls", though adequate to hold art deco fruit, completely inadequate to be used as a Nose Cone or any other submarine part. This lead to: Design Modification (#1).

     Design Modification (#1), the First major design modification was the elimination of all COMPOUND CURVES from the "computer modeling program". After extensive reprogramming the "computer" finally produced ...Sub-Lime as you see it in its present form. By the way... it was the "computers" wife who named the sub: "Sub-Lime". (As an aside, the original name offered was Sub-A-Dub-Dub. This name was rejected because it was decided that if by some fluke we did excel in this undertaking, a more Dignified name should be recorded for posterity, and I had already purchased lime green hats for the Team. Since little, (read no) research on existing names was conducted, the similarity of this name Sub-Lime, to other "sublime's" is purely coincidental, and should not be considered an endorsement, though plagiarism is completely within my ethics.)

C - Construction

     All construction was conducted on the porch of our house, as at this time I am without garage.

(a) - Pattern Making

     Full scale patterns and mock-up of the entire vessel was fabricated in wood and particle board. This stage of development was know as the "coffin" stage for obvious reasons.

(b) - Model Making / Testing

     An Acrylic model of the hull was made in a 1 inch to 1 foot scale. (This model also served to test the bonding characteristics of the welded acrylic joint.) The Model was Pool Tested and proved to exhibit excellent longitudinal stability. (Which was just fine, as the event was set up as a timed straight line course.)

(c) - Construction

     Sub-Lime was constructed in three sections, A Nose and Tail Cone segment, and the Main Body.

     The Nose/Tail Cone assembly was constructed over a wood frame (which was later removed), the pre-cut acrylic sides were screwed to an inner frame, a solid nosepiece was welded (acrylic cement) then contoured, then the upper and lower acrylic sheets (not shaped) were fastened and welded. After welding a router was used to shape the top/bottom acrylic sheets to conform to the port/starboard side pieces. The wooden frame was removed, and an acrylic partition fitted to provide a watertight compartment open on the bottom and the entire Nose/Tail assembly was fitted to a Marine Plywood Bulkhead frame, this Bulkhead frame connects to a conforming mate on the main hull. This provided a rigid attachment and a viewing port to forward. The Nose/Tail Cones provided three functions (a) streamlining, (b) forward visibility, and (c) a buoyancy chamber with capability to add and vent air.

     The main hull was constructed around and plywood deck over a keel and attached to a fore and aft bulkhead (mate for the nose/tail segments). Pre-cut sides were affixed to the permanent deck, and a matching jig parallel to and superior to the deck. Acrylic blocks were welded to the inside edges of the hull sides, and the top/bottom acrylic sheets were fastened using stainless steel screws to these blocks. A router was again used to contour the top/bottom sheets to the sides. Hatches and ports were cut from the separated top acrylic sheet and subsequent ports were drilled as needed.

     All control surfaces and control surface fittings was constructed from acrylic and or wood. Linkages were made of plastic weed-wacker line.

     The propulsion system consisted of a pair of oak Oars, with a hinged curved acrylic blade on the end of each. The blade was able to fold back during the recovery stroke, and extend to a fully open position via the use of rubber bands, for the power stroke. The oar shafts fit in a block within the hull to keep them on a horizontal plane, and they pivoted around a single pin. The oars are of a foot powered design. The propulsor lies on his back feet to front, with forward vision provided by looking forward through the open bulkhead at the nose. Control surfaces are operated with the hands.

III - Pool Testing

     Three pool sessions were planned, and used. The first was to determine and set the Buoyancy Characteristics, the second was to determine the effectiveness of the Propulsion System, and the Third was to learn the Performance Characteristics of the vessel. In short: Does it Float, Does it Move, How do you Drive this thing.

A - Pool Test #1 : Buoyancy Configuration (Does it Float)

     The purposes of the first pool test included: (a) to determine the buoyancy characteristics of the sub and fix it as needed; (b) a test the functioning of the bow and stern ballast (flotation) tanks; and (c) examine the longitudinal stability of the design.

     The intended buoyancy characteristics desired of the vessel is such that the Center of Buoyancy (CB ) was above the Center of Gravity (CG), and the overall submerged buoyancy of the vessel was Neutral in the water column (it did not float or sink).

     Having the CB above the CG insured a static stability in its operational orientation of "top side up, and bottom side down". (I did not want the sub to have a tendency to flip over).

     Having the sub Neutral in the water column allowed for neutral placement of all control surfaces while the sub was moving through the course. This ment that no forces from the control surfaces were to be acted on the sub while it was moving, thus no additional drag would be induced during motion.

     Initial calculations estimated the vessel to be about 30 pounds negative (heavy). Approx. 1/2 cubic foot of Closed Cell Foam was placed below the floor to counter this calculated effect. When the sub was placed in pool for the first time, it immediately flipped over and assumed a floating position. The 1/2 cubic foot of foam was removed, and an additional 30 pounds of lead was affixed to the keel. Sub-Lime was now neutrally buoyant, and had a desirable orientation in the water column. It turns out that I underestimated the buoyancy of the wooden members of the vessel (floor, keel, bulkheads, bulkhead support, oar box, and oar). The Nose and Tail Cones are the Bow and Stern 'Ballast' (actually floatation) Tanks. The compartments are open on the bottom, with a vent valve (dump) on the upper aspect. An air line (from a low pressure side of a scuba regulator) with selectable valves to each tank is fitted. These tanks were designed to provide a means of keeping the sub on the Surface without additional external apparatus, and also to compensate the vessels buoyancy changes while in operation as future demands may place on it. (It was planned to convert Sub-Lime to an electric powered diver propulsion vehicle for my wife and I after the race. That would mean adding batteries and electric trolling motors, i.e. more weight. I decided that now was the time to build in these buoyancy chambers.)

B - Pool Test #2 : Propulsion Testing (Does it move)

     This was the test to see if all the theoretical design work and the many hours in construction had any merit. Would Sub-Lime Move or not.

     I must recount a potentially life threatening incident. It happened just prior to the first test of the propulsion system while I was strapped into Sub-Lime. My feet were tied to the oars with a copious amount of one-inch webbing, as the elastic foot bungee attachments had not been constructed yet, and what do you think happened? The mouth- piece of my regulator separated from the body of the regulator. I did not have an alternate air source at this time either, though in all subsequent in-water activities a Spare-Air bottle was close at hand, (in a pocket in the leg of my wetsuit). A precarious situation presented itself, and do I need to mention that even though there were three other divers around me, no one immediately recognized what was happening. I do not think that I could have removed the waist belt holding me to the sub and untied the restraints on each foot in time to prevent an accident. The only reason a near drowning did not occur was because I was in the shallow end of the pool, in about 2 feet of water, I simply sat up and my head was above the surface. Definitely got my attention. (Submarine racing is a death defying experience.)

     Sub-Lime had to be propped off the pool bottom with a dive mask box (provided by Ron Edmundson) in order to take the stress off the oar blades, as they extended below the plane of the keel. It was with much excitement to the team seeing Sub-Lime move under its own power, with the first thrust given by the oars. The length of the pool was made in short order. Divers recovered the vessel, and returned her to the shallow end.

     Ron noticed that the Blades over-rotated during some power strokes. A fix was instituted where a screw was placed on the oar shaft which prevented the blade from over- rotating.

     A second run was made. At its completion, while floating on the surface, the starboard hull was damaged when too much pressure was applied to the gunwale. I broke it, thus ending pool testing for this day. A successful day it was. Sub-Lime was returned for repair and modifications.

(a) - Design Modification (#2)

     A major performance flaw was evident in this initial dynamic test. The control surfaces were slow in affecting the vessel. Most notable in a nose up/down attitude. The design characteristic of the control surfaces are as those in a "tail dragger" aircraft. The need for a Bow "dive plane" was evident, and fabricated prior to the next pool test.

(b) - Hull Repair

     Hull repair was uneventful, acrylic is a very easy material to work with as far a welding patches is concerned.

C - Pool Test #3 (Final Test) : Performance Envelope Development (Learning how to Drive)

     This final pool test was to learn how to drive this beast, and determine just what the overall performance characteristics are. A bow plane was fabricated that was controlled by a line/pulley-under-tension arrangement as with the other control surfaces.

(a) - Design Modification (#3)

     The addition of the bow plane produced marked improvement in control over what was experienced without it, though larger control surfaces would have been an advantage. (The boat goes too slow for the size of the control surfaces). The main problem was in controlling the bow plane. As the moving surfaces became wetted the wood axle swelled resulting in increased friction which prevented smooth movement of the bow planes. A modification was undertaken where a direct rigid linkage was substituted for the pulley arrangement, and tolerances of fit were enlarged to take account for expansion of wooden parts as they became wetted. (Increased the slop.)

(b) - Design Modification (#4)

     Probably the most significant design modification was to substitute rigid closed cell foam to trim the sub neutral in buoyancy in the water, instead of using air the bow and stern tanks for fine tuning of the sub underwater. The large volume of the tanks allowed too much movement of the 'air bubble' within them. This movement made it all but impossible to stabilize the vehicle underwater as the air bubble, and its movement arm kept on moving,. The completely air filled ballast tanks work perfectly to allow the sub to float easily on the surface between runs.

IV - The Race (World Submarine Invitational 1996)

     Final modifications are completed; race day has arrived. Delivery to the basin, assembly, pre dive briefs and launch proceeded smoothly. It was a very handsome team with their lime green hats and margarita in hand, (OOPS, that comes later) that presented themselves at the Offshore Model Basin.

A. - Five Successful Runs

     In the four hours of pool time allocated, a total of seven runs were attempted, five were successful, two were incomplete. The cycle consisted of keeping the sub on the surface until our time was called. Then two safety divers would swim the sub to just in front of the first timing trap. The sub would then blow ballast tanks allowing it to submerge with the help of the safety divers. The safety divers would settle into a position of standing on the bottom of the basin in 15 feet and hold the nose and tail in an orientation parallel to the basin floor. When "Sub-Lime got the Green", the signal to start a run was received, the divers would let go, and the propulsor would commence his run. I rowed through the course, and after passing the end of the speed trap, I would fill the bow and stern ballast tank and breech to the surface. (The event sponsors allowed a 150 foot run up area, which I choose not to use for two reasons, (1) pool testing indicated that Sub-Lime would not go much faster with a longer acceleration run due to the inherent design of the propulsion system, (the faster the speed through the water the shorter the power stroke), and (2) the marginal maneuverability of the vessel would allow a greater amount of time to go out of control. (The last thing that I wanted to do was "Crash and Burn" before the starting line.)

B. - Two Unsuccessful Runs

     The first unsuccessful run resulted in exiting the course to the port side. I had been applying power to each oar equally and simultaneously at this time, and was experiencing a greater force pushing the nose to port. The curve of the blades were not symmetrical. The starboard blade deployed prior to the port, thus a greater (sooner applied) force on the starboard oar pushed the nose to port. The fix became to alternate oar strokes, where alternate strokes of varying intensity could be applied to keep the nose on the centerline of the course. (I was unable to power the oars at the same time but with a different amount of force on each one. It was much easier to alternate strokes).

     The second unsuccessful run was due to a failure of the port foot-bungee-to-oar cable tie(s). I experienced a port foot-oar separation and not being a centerline thrust propulsion system, the vessel took an violent jog to port. (And at the terrific speed I was traveling at, the induced G-forces almost caused her to "Break Up" as Scotty would say. Sub-Lime was only designed for a G-force loading of 9 positive and 3 negative, but she held together nevertheless.)

V - Lessons Learned

     At no time was stress placed on the vessel or the propulsor as Participating In The Event was the objective, (i.e. I did not try to use maximum strength in the event as I was trying to avoid breakage of the propulsion mechanism, or anything else. I did try to increase the force applied to the oars after each run through the course, as I was getting a feel on the vehicles ability to withstand each subsequent greater force applied to it.) The object only was to Successfully Participate in this event, and only after experience gained in this race would further participation concentrating on Speed be attempted at other races.

     It turns out that the design of my propulsion system makes Sub-Lime’s speed self- limiting. I do not feel that a stronger propulsor would have any significant effect on the speed of the vessel. The fact that thrust applied to the sub from the oar is of a short duty cycle, and as the vessel increases in speed the amount of time the blade is fully open to provide thrust decreases. Thus the faster the boat moves, the shorter the thrust vector is operating. (What is happening is that at the end of the recovery stroke/beginning of the power stroke the blade is folded. When the boat is in still water, the elastic band pulls the blade to the full open position, and a power stroke can begin. When there is water moving over the hull the elastic band cannot totally overcome the force of water over the blade, thus the blade is not fully open at the beginning of the stroke...and part of the power stroke is used to first open the blade, and then continue to provide new thrust. The faster the boat goes through the water, the greater amount of "stroke" is used in just opening the blade, thus less and less of the stroke is devoted to new thrust. (It is obvious that a propulsion system which produces a constant thrust (propeller/pump/paddle wheel/etc.) has an advantage over a propulsion system which has a short "duty cycle".) It was to my benefit that the other four competitors were unable to successfully overcome the many obstacles and challenges which is presented in this Underwater Human Powered Submarine Event.

     Having completed the course not only once, but five times proved a successful accomplishment of all project objectives. Being able to recover from malfunctions, and changing scuba cylinders in under four minutes while in the water showed an above average ability in team coordination. Most important all members of the "Dream Team" had more fun than they expected, and having set a World Record in the event was, what can I say Sub-Lime.

VI - Thanks

     Thanks to Kevin Hardy and Jim Richardson and all those who helped put on the 1996 World Submarine Invitational for creating a truly world class event.

     I thank all members of Sub-Lime’s Dream Team for all the help they provided in making Sub-Lime a success. (I am glad everyone had fun playing with my pool toy.) I especially thank my wife Jane for allowing the completion of Sub-Lime’s construction in our living room, as an unforeseen snowfall prevented any further construction on the porch. (She now takes note when I say "Honey, I think I can...)