Edward Leibolt is an ocean engineer at the Naval Surface Warfare Center, Carderock Division. He is a 1981 graduate of Florida Institute of Technology and has worked in the submarine acoustics department at NSWC Carderock Division for 18 years.

He assembled a volunteer team of NSWC Carderock Division engineers/scientists to develop the human powered submarine "TURTLE" which was entered in the first International Submarine Race held in 1989. Since that time, he has been the leader in the development of human powered submarines at NSWC Carderock Division, "TURTLE II", "BULLDOG" and "SCUBA-DOO". BULLDOG and SCUBA-DOO are submarines that were designed and built by local high school students under his mentorship.

In preparations for the Sixth International Submarine Race, he served as the NSWC Carderock Division facilitator for the testing of BULLDOG, SCUBA-DOO, and University of Maryland's entree TERPEDO. In addition, he served on the International Submarine Race Committee preparation team.

Vincent asks:
I am a 15-year-old kid who wants to build something new. Where could I get the basic design for a man operated sub? I do not plan to race or anything, but I need something to work on.

Leibolt's response:
There are no books on this subject, but designs have been submitted to the ISR Organization and they may have some information for you.
Their address is :
ISR Organization
P.O. Box 563
Allentown, NJ 08501

Adwait asks:
I wanted to know if you have ever thought of using a gear system to propel your subs faster. The rider could switch gears while pedaling after reaching a critical speed to increase the revolutions of the propeller. This could also be done automatically by a computer when the propeller has reached a certain RPM.

Leibolt's response:
This idea has been tried in the past races with poor results. The gear switching mechanism has typically been a bicycle derailler which seems to always cause the chain to fall off during the gear changing process. What we have found is that the propeller obtains design speed in about 4 revolutions on the pedal crank, so changing gears would not really help past the first 10 feet or so.

Jules asks:
What materials was the sub made of? How did you construct the sub? How much money did the sub cost?

Leibolt's response:
Most of the submarines are constructed of fiberglass. In past races, teams have used drop tanks from planes, plexiglas, and polycarbonate for the hulls There are numerous construction techniques that are used for the submarine hulls.

In past races, teams have been judged on their innovation in constructing the subs while reducing the cost. Some subs have been built using a female mold, others have used a foam male mold to form the hull around and still others have blow molded plastic (plexiglas or polycarbonate) to form the hull. We constructed our submarines using foam rings that were cut out individually and glued together. Fiberglass was applied to both the out side and inside to form a sandwich construction which is both strong and light.

The cost of the submarines are based on the design effort that goes into each one and the labor costs to fabricate. Hence, some submarines are very expensive to produce. I can only speak for the ones we have fabricated. Our subs cost about $3000 for materials and equipment. Our time was all volunteer, but I would estimate the cost for labor would be about $10,000.

Ellen asks:
Have any innovations from the student sub contests crossed over into the real sub or ship building industries?

Leibolt's response:
To date, I know of none. But I would expect that both the knowledge and experience that the students have gained designing and testing their subs will show up in future real world work.