Submarine racing has been an international competitive sport for over
two decades. The first race, involving 17 submarines, that was run by
the US based International Submarine Race (ISR) organization
), took place in the sea just north of West Palm
Beach Florida in 1989. Last year I attended their 12th ISR meeting where
21 subs from 19 teams competed in the giant freshwater David Taylor
Model Basin, part of the NAVAL Surface Warface Center, Carderock
Maryland. This kilometre long testing tank is used by the US Navy for
the testing of ship models. In the late 1940s the model basin was used
to investigate efficient shapes for a proposed new generation of fast
submarines. This culminated in the development of the United States
first post war fast sub, the USS Albacore.
The human powered racing subs are wet-subs with no pressure hull, and the crew breathe air using scuba equipment. The subs fall into four categories: one or two crew with propeller or non-propeller drive. I was a guest member of a team from the Rhine Waal University, Germany, led by Prof. William Megill. Their boat, the Rivershark was a single occupant sub with a non-propeller drive, consisting of two large lunate shaped fins moving counter to each other as the driver peddles; a swimming stroke that might be adopted by mating whales.
The ISR race is an underwater drag strip for one sub at a time. Top speed and average speed, along the 100 metre course, are measured using synchronized video cameras. Each sub is allowed up to five trials a day. This is ambitious given the breakages that occur on racing machines. Crisp and clear instruction to start pedalling the sub (Rivershark, Rivershark, Rivershark, bail, bail, bail) were delivered to our ears from the start line officials using hydrophones. A surface inflatable occupied by Navy divers followed close behind the sub. At the end of the subs run, the Navy guys came down to retrieve the driver and sub.
The best speed, a world record of 7.28 knots (3.8 m/s), was achieved by a single occupant propeller driven sub from Montreal (École de Technologie Supérieure). The team I was with was much slower but, importantly, finished the course! Our first success was greeted with cheers from
A take-home message for me was that speed is not a primary concern. Buoyancy and steering are more important. Without good attitude and yaw control a sub could crash into the bottom or surface prematurely. Also pitching up and down or drifting from side to side substantially increases the drag on the vessel, slowing it down.
Our Taniwha that is currently under construction is scheduled to take part in the very next international competititon: the 2nd European International Submarine Race (
), 7-11 July 2014, to be held in the largest swimming pool in Europe, the 120m long by 60m wide QINETIQ Ocean Basin testing facility near Portsmouth; a football field underwater. The race will involve 11 other submarines from around the world: (
). This race is different to the US one for it includes a slalom course. For this we will need good
The Taniwha will provide our lab with a new platform for student projects that will research underwater human propulsion, navigation and surface communication, leading to improved underwater craft. Last year two of our Engineering project students (Susan Sun and Kelly George) produced a proof of concept electronic buoyancy and attitude control system. Our aim is to fit this to the sub. There will be many other things to do.
But this year our goal is simple: to produce an internationally competitive racing machine!
In Maori mythology, taniwha are beings that live
in deep pools in rivers, dark caves, or in the sea, especially in places
with dangerous currents or deceptive ocean waves.
Acknowledgements: Team Taniwha gratefully acknowledge the help provided by our sponsors that include Jackson Electrical (Onehunga), The Department of Engineering Science (University of Auckland), The Auckland Bioengineering Institute, The Centre for Advanced Composite Materials (University of Auckland), Stretchsense Ltd, and Dive New Zealand magazine.