SCUBA Diving and the Defining Key Principles of Usability

SCUBA Diving and the Defining Principles of Usability

Since explorer Jacques-Yves Cousteau and engineer Emile Gagnan developed a method for commercial SCUBA diving and then popularized the beauty and enjoyment of spending time underwater, SCUBA diving has grown in popularity.  In the past, learning to SCUBA dive was a long and arduous process only performed by highly trained specialists, while today there are short courses that teach the fundamentals in just a few hours followed by guided SCUBA excursions. was once dangerous and extreme is now far more pedestrian, but the experience of breathing underwater is still unique and interesting.  Taking the complex and dangerous world of SCUBA and making it both relatively simple and far safer is a triumph in the dive community.  Much in the same way, user experience professionals seek to take the complexities of technology and make them easier to use.  SCUBA diving offers a unique prism through which it is possible to better understand user experience design and user interface design.

Problem Solving

Emile Gagnan was an engineer.  Gagnan’s prime task was to solve a problem: how can a person breathe underwater for an extended period of time?  It should be noted that underwater exploration has a rich history and Gagnan was not the first to tackle such a difficult issue, but his design evolved in to the common dive gear that is recognizable today.   While Gagnan was an engineer, he was also a designer.

All designers are problem solvers.  Graphic designers sometimes feel uncomfortable at considering themselves as problem solvers, but in fact, all designers are problem solvers.  Gagnan and Cousteau solved a myriad of problems related to undersea breathing, just as their web and mobile design counterparts solve a wide spectrum of problems ranging from how to get more subscribers to a newsletter to how to rebrand a product.  Like Gagnan and Cousteau, user experience designers are tasked with the difficult job of taking complex ideas and making them both approachable and usable.

Where UX Meets UI

Through the lens of SCUBA diving, all the equipment used by divers would be the user interface and the actual feeling of breathing underwater would be the user experience.  This separates user experience design and user interface design in to two types of solutions.  User interfaces solve questions about how something works, while user experience refers to how something feels.  In SCUBA diving, the equipment influences the feeling of diving, just as in user experience design; interfaces influence the feeling of using a website or mobile application.

User experience design and user interface design can be divided in to countless job titles, sub-categories, and tasks, but they also merge in many places which is why UI and UX are often grouped together.  Usability is often the meeting point between user experience and user interface.  SCUBA equipment was originally very difficult to use, but has evolved in to equipment which is relatively easy to use.  While the equipment itself is easier to use, its technical complexity has increased with time.  This is very similar to the path of web and mobile technologies which have become far more complex, but can also be far easier to use today than in the past.

While delving in to the complexities of user interface design and user experience design is beyond the scope of this article, a few critical and key principles can help to demystify user experience and user interface design.

Hicks Law & the Rule of Sevens

Hicks Law states that the more options a user has, the longer it will take them to make a decision.  Consider that most SCUBA divers rely on several different gauges to chart their depth and to know how much air they have left in their tanks.  Additionally, most divers dive with a watch and use decompression tables to avoid getting decompression sickness.  A compass is often included in SCUBA diving equipment as well.  There are a plethora of gauges that SCUBA divers need, but if the more gauges they have, the more likely they are to be confused.  Confusion underwater could lead to death.  For this reason, the gauges are often split between those found on the diver’s wrist and those connected to the air tanks.  The two locations allow the diver to more easily break the information in to parts and to digest it.

In web and mobile design, the same concept holds.  Users who are overwhelmed with information will have a difficult time using an interface or making decisions.  If, for example, the decision is whether or not to buy a product, the effect of poor usability could have a negative impact on sales.  A good rule of thumb is to consider the Rule of Sevens.  If users are given more than seven options in a menu it can be overwhelming.  Many studies have shown that after seven options, people begin to forget the initial options.[1]  Allowing for fewer more direct options will help users to make choices and increase usability.

Fitts’s Law

Fitts’s Law is based on a math equation, but simply put: the bigger the button, the easier it is to click, and the easier it is to click the faster the user will do so.  If a diver’s mouthpiece is flooded with water, it is critical to remove the water in order to breathe.  To do so, divers have just one button to push and the button is large.  This is done on purpose.  The larger the button, the easier it is for the diver to find it and press it in times of emergency.

Few websites deal with life or death situations, but many websites and applications want their users to click on certain areas of the site.  Fitts’s Law can help to increase conversion rates.  The recent web trend to increase font sizes and to have larger icons is due in part to the effectiveness of Fitts’s Law.  One of the main tenets of usability is the ease at which a user is able to find information on a page.  The larger the information is, the easier it is to find.  This also leads to more distinct hierarchies which can also help improve usability.

Pareto Principle

The Pareto Principle is most often referred to as the 80-20 Principle.  In the user experience community it is most often used to describe how eighty percent of users will use twenty percent of a website or application, while twenty percent of users will use eighty percent of a website or application.  The application in SCUBA diving is that eighty percent of diving accidents come from twenty percent of potential problems.[2]  SCUBA instructors, knowing that this is the case, can thus focus their efforts in to improving the smaller percentage of issues that have a disproportionate effect on diver safety, rather than focusing on a wide berth of issues that lead to a smaller number of incidents.  Likewise, making small changes to help users better navigate a website can have a large effect.


Just as SCUBA diving’s popularity grew from the intersection of an engineer and an explorer, so too does the popularity and importance of usability stem from the intersection of user experience and user interface design.  Like explorers and engineers, user experience designers and user interface designers are problem solvers.  The world of technology and computing, like that of undersea exploration, is vast.  Just as Jacques-Yves Cousteau made the undersea world approachable to men and women around the world, so must user experience and user interface designers make the web and mobile worlds welcoming and easy to use for users from all over the globe.


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