The story of the underwater viewing vessels.
The idea to study marine mammals underwater seems very obvious, but how do you do it? You can see them when diving or snorkeling, but that will only last for a few seconds in the wild, unless they decide to stay near you. And even if you could keep up with them in the water while snorkeling or scuba diving (I spent years trying to figure this out), they will likely react to you as another animal, affecting their behavior, so your observations will be biased. So, the way to do it would be to use a vessel from which you can view the dolphins underwater. This can also affect the dolphins’ behaviors, depending on how the vessel is handled, but you are no longer treated as another animal.
The first version of this type of underwater viewing vessel came together in the mid-1960’s as a result of discussions between Dr. Ken Norris and his friend Jimmie Okudara on Oʻahu. Ken wanted to study dolphins underwater and Jimmie owned a machine shop in Honolulu. Jimmie put together an airplane fuel tank and an “aluminum hatch” or viewing chamber, a tube with plexiglass windows sticking down from, and permanently attached to the bottom of the fuel tank. This craft was formally named the MOC (Mobile Observation Chamber), but later became known as the SSSM (Semi-submersible seas-sick machine).
The SSSM was initially towed behind another vessel, but was later modified and powered by an outboard engine. It became the first in a series of underwater viewing vessels that Ken Norris and his students and colleagues used to study Hawaiian spinner dolphins in Kealakekua bay on the Kona Coast of the Big Island of Hawaiʻi. The SSSM allowed for great underwater observation opportunities of dolphins. However, in addition to being very slow moving, it had other drawbacks as the nick-name implies and was mostly used in the protective waters of Kealakekua Bay.
The next underwater viewing vessel designed by Ken and his group “was built from the discarded fiberglass hull of a Boston Whaler cathedral hull sport craft. In essence, construction consisted of replacing the bottom of the vessel with an elongate viewing box in which an observer lay prone” (Ken Norris and Randall Wells, Observing Dolphins Underwater, p. 59 in Chapter 3 of the book ‘The Hawaiian spinner dolphin’). In this vessel, the viewing window was angled down, allowing the viewer to look down at the dolphins below the vessel. It was initially built to be used in the Eastern Tropical Pacific, to find “solutions to the massive kill of dolphins in the seine fishery” (p. 59 in Chapter 3 of The Hawaiian spinner dolphin) for yellowfin tuna. However, it was also used extensively in Kealakekua Bay to study the spinner dolphins in this protected bay. And just as the SSSM, it was very useful as long as sea conditions were favorable.
One drawback with this vessel was that you could not look up underneath the dolphins in front of the vessel. This is important since it is the only way to definitively determine the gender, or sex of dolphins, more about that in a future blog. Another drawback, shared with the SSSM, was that both these vessels always had their viewing windows permanently in the water, which meant that each research day had to begin by jumping in the water to clean away the algae growth on the windows.
This last problem was solved in the third underwater viewing vessel, designed by Ken and one of his graduate students, Dr. Randy Wells. I spent a few years of my doctoral program completing the construction and sea testing of this vessel under Randy’s supervision. I was also given the honor of naming it and named it Smygtittar’n (the literal translation from Swedish is: “the Tip-toeing looker”; aka: peeping tom). It quickly got the nickname the Smyg.
This vessel had a viewing chamber hanging in an A-frame in the middle of the vessel, with the viewing windows located just below the hull. However, when it was not in use and pulled up, the viewing windows were out of the water, thereby never having a problem with algae growth. In addition, since the chamber was out of the water while looking for dolphins, the vessel was considerably faster than its predecessors, reaching speeds of up to some 16 knots. As a result we could cover a lot of coastline looking for dolphins.
The Smyg also had a substantial drawback, that only showed up in very special situations, but I will address that, as well as, its benefits, and all that we were able to accomplish in the next blog.
Books where Ken and his team describe the various underwater viewing vessels.
Norris, K.S. (1974) The Porpoise Watcher: a naturalist’s experiences with porpoises and whales. New York: Norton.
Norris, K.S. (1991) Dolphin Days: The life and times of the spinner dolphin. New York: Norton.
Norris, K.S. and Wells, R.S. (1994) Observing Dolphins Underwater. Pages 54-64 in: Norris, K.S., Würsig, B., Wells, R.S., Würsig, M. with Brownlee, S.M., Johnson, C., Solow, J. (1994) The Hawaiian Spinner Dolphin. Berkeley: University of California Press.