Feature Interview: Brett Hood, Member of Odyssey's Elite Side-Scan Sonar Search Team
What is side-scan sonar imaging and why is it essential to deep-ocean shipwreck exploration and recovery?
In simple terms, side-scan sonar imaging is the process of acquiring images of the ocean floor using sound waves. There are several types of sonars but because side-scan sonars are towed behind the ship on a cable it allows the sonar to be "flown" at shallow altitudes that provide detailed images of shipwrecks. The reflected acoustic returns, also known as sound echoes, create an image similar to an aerial photograph. It is important that the side-scan technician consistently monitor the height of the towfish above the ocean floor. If the towfish gets too close to the seafloor or if an unexpected undersea mountain appears, the fish may crash and can be lost or damaged.
What kind of things does side-scan sonar imaging detect, and what are the most fascinating objects or sites you’ve discovered and surveyed?
Side-scan sonar can detect any number of things and while we use it for looking for shipwrecks, it can also be used to investigate pipelines, underwater cables and has even been used to locate underwater mines for the military. I would have to say the most interesting sites we've discovered are the older shipwrecks. It's fascinating to see the many historic objects and other relics including armament such as cannon that were used aboard ship so many centuries ago.
Why do side-scan sonar specialists sometimes call scanning work "mowing the lawn"?
When conducting side-scan survey operations a search "block" is set up. These blocks contain many lines and when searching in these blocks the ship will pass over one line then turn around and pass over another line in the opposite direction, much like someone "mowing the lawn". During this initial survey, the side-scan sonar towfish is towed behind the research vessel about 60-200 feet above the seabed. Depending on the depth of the water, the towfish may trail a mile or more behind the research vessel.
Once you find something of interest in your search, do you get to be a part of the ROV inspection?
Typically I'm not involved in the Remotely Operated Vehicle (ROV) inspection although I have been on several occasions and it's always exciting to see what our "targets" end up being. Even though the target may not be what we're specifically looking for, we never know until we put the ROV in the water. When I am involved in the ROV inspection process, I generally help out with the launch and recovery and the navigational aspect of the ROV dives.
What type of things do you do aboard the ship when you're not on duty?
I've been playing guitar for a long time and I always bring one with me. I also read a lot and watch plenty of movies. We also have gyms on the ships so I try to spend some time working out several times a week.
When you're not busy offshore searching for shipwrecks, how do you spend your time?
I've recently bought a motorcycle and I can't seem to stay off of it when the weather cooperates. I also spend time rebuilding an antique Steinway piano that I've been working on for far too long and which should finally be finished this year. I've been playing guitar for over 20 years and I play a lot when I'm home as well as offshore. Other than that I try to visit my family and see my friends as much as possible when I'm home.
Have you always been a side-scan sonar technician?
I've been fortunate to have had a few interesting jobs before working for Odyssey. When I was 24 I decided to join the circus for a summer. I'm still not quite sure how it happened but I became the ringmaster for the show and my summer job ended up lasting five years. After I decided to "retire" from my circus career, I started playing around on the piano which led me to become interested in the tuning aspects of the instrument. I learned piano tuning and repair from a local piano technician and ended up doing that for several years prior to working for Odyssey.
What was the most exciting experience you've had while working for Odyssey?
Everyday on the boat is an adventure. Because of what we do, we never really can anticipate what the day will hold or what we will find! We've discovered so many cool shipwrecks, including the 1744 wreck of HMS Victory. Knowing that I was a part of the team that found this historic shipwreck is an especially thrilling experience for me. It's a great feeling to be involved in a discovery that finally solved this centuries-old mystery.
One of the most interesting experiences for me was watching a fellow technician get airlifted off the ship because of his appendix. It wasn't necessarily a "fun" experience given the condition of my colleague but it was fascinating to observe the entire airlift event. I also especially enjoy the traveling that comes with working offshore and having the opportunity to see other parts of the world.