The Undaunted. 16 foot, 750 pound
1. Building a Wet Sub: Lessons Learned the Hard Way Doug Farrow
2. The Undaunted 16 foot, 750 pound “two-man” wet sub
Fiber-glassed one-inch marine plywood
Two rear-mounted trolling motors
Two rudders and one hydroplane operated by levers and pulleys
Double keels for grounding
Two bilge pumps
Standard scuba tank with regulator
3. Why the “Undaunted?” I asked for suggestions from friends and family
My sister suggested “Undaunted”. Other suggestions included:
The Blue Canoe
The Blue-Boat U-Boat
The Plywood Coffin
4. Reference Library Photocopies from various encyclopedias
WW II submarine books
Articles from Popular Mechanics and Popular Science
The plans from the Markham Boat
Two man wet sub featured in Popular Mechanics and built from drop tank
5. Why 1971? I was in the Air Force 1969-1973
I had just returned from Vietnam
I had time on my hands
I was single
I was in Florida near water
I had wanted to build a submarine since seeing Walt Disney’s 20,000 Leagues in 1954
6. Design Philosophy Make it sturdy
Stay above 33 feet
Use existing skill-sets
Use commercial components
Two person crew
Comfortable on the surface
7. Construction Venues Drawings and scale model in barracks
Initial construction in buddy’s front yard
Continued construction in woman’s back yard (backs to a lake)
Component assembly in friend’s garage
Testing in St. Petersburg
Operations in Tampa Bay
8. My Biggest Mistake I envisioned cruising out and back from the dive site sitting atop the conning tower, using the sub as a boat.
Because of the instability caused by the flat bottom, I had to seal the hatch and flood down at the dock. It was very stable under water.
9. Because of the Flat Bottom I could not use the anchor, the paddle or the jump seat on the conning tower
I did not need the hydroplane, because the huge flat bottom acted as a hydroplane when I trimmed backward
10. I Failed to Account For System Interactions The rudder and hydroplane levers worked great
Adjusting trim by rolling my seat forwards and backwards worked great
But when I went to push forward on the levers, my seat went backwards, and my nose pitched up
Solution: Installed a handle to hang onto
11. Electrical System Knowing nothing about electricity, I simply copied the Markham parts list
Grossly underpowered: 3 times as heavy
Markham said nothing about out-gassing during battery charging or discharging
Mounted controls on upper surface of conning tower, prevented diver egress
12. Steering System Dual rudder system controlled by pulleys worked surprisingly well
Between the rudders and hydroplanes: 30 pulley wheels
Steering was fine, but navigation was not. I was so low in the water I could barely see.
13. Ballast System Moved from bricks to re-bar
My conning tower was my ballast tank, and the hatch seal leaked constantly. I could not maintain depth
14. Two Person Crew No one would dive with me, so it became a one man boat
Very scary all alone in the middle of Tampa Bay
In the end, the range of motion required by my “trim system” would have prevented a second crewmember anyway
15. What I Did Right I actually built a PSUB
It may have been clumsy, but it sure was fun
I learned more about submarine building from that than from all the books I read
I never dived in water deeper than 30 feet
16. What I Learned A PSUB is an integrated system. One major design flaw (e.g. flat bottom) ripples throughout the rest of the design.
Solicit advice from people who know more, not less, than you do.
Re-read the books you read when you were first learning the business.
17. What I Learned Get a workshop.
A submarine is a boat.
Do not implement systems you do not understand.
Negotiate your submersible activities with your significant other.
Be sure you assistants do the same.
18. Think Trough The Entire Lifecycle During Planning Analysis
Paper, Computer, Mockup
Hull, Components Testing
19. Questions? “There are no stupid questions, only stupid people” (joke).