NOAA Teacher at Sea
Onboard NOAA Ship Delaware II
May 14 – May 25, 2012
Mission: Northern Right Whale Survey
Geographical are of the cruise: Atlantic Ocean out of Provincetown. MA
Date: May 17, 2012
Weather Data from the Bridge:
Winds out of the Northwest, 5 to 10 knots. Mid-level clouds.Ocean swells 1 to 3 meters
Science and Technology Log:
We pulled up anchor and set sail out of Provincetown, Cape Cod at 6AM. We followed the Cape Coastline for several miles and then headed out to Georges Bank again. Unfortunately, today was windy so the ocean had a lot of whitecaps. In addition, the swells were between 1 to 3 meters throughout the day. This made it hard to spot whales. The wind also disperses their spout very quickly so they are hard to see. Around 3PM the wind lessened such that there were far fewer whitecaps. We started to see more whales but not a lot.
One right whale came close to the ship and we were able to slow the boat down and get several pictures. Other than that we saw fin and sei whales and one minke whale. A bit of excitement for me, though, is that several pods of common Atlantic white sided dolphins swam past the ship. One pod had about 15 dolphins!
The last time we were out at sea we took the little gray boat out to get closer to the right whales. One of the whales was entangled. Entanglement is when a gillnet, lobster trap or crab pot or any other marine debris gets caught on a whales fin, head or flippers. It is the second leading cause of human-related right whale deaths. In fact, nearly three out of four whales bear scars from these types of interactions.
NOAA created a central response network on the East Coast through its National Marine Fisheries Service, developed by the Provincetown Center for Coastal Studies. When a whale that is entangled is spotted, they send out a crew to remove the fishing gear from the whale. Now this is no easy task. Remember whales can weigh up to 70 tons and won’t just sit still for you to remove the nets. Responders will typically try and slow the whale down and keep it on the surface. In order to do this they attach buoys to a trailing line in order to cause drag on the animal. Fin, sei and humpbacks react well to this because they are lunge feeders so they actively chase after their prey, and because of this they experience this periodic drag. Once this happens and the whale has slowed down, the responders get close in a small inflatable boat and try to remove the nets with strategically placed cuts, working to remove the net as quickly as possible. They use tools that are on the end of long poles to do this.
However, this method does not work well with right whales. They are grazers and therefore oftentimes don’t react to additional drag. Jamison Smith, biologist for NOAA, said that they even attached a large boat to the drag line but the whale just kept swimming and eventually broke the line! So they have been trying something new with them. Recently they have administered tranquilizers to the whales to slow them down. They found that this changed the right whales behavior, and they were able to get closer. They have even administered antibiotics to those whales that had severe damage from the fishing gear. View this video to see a whale getting darted. NOAA Biologist Darts Right Whale (courtesy NOAA)
Researchers continue to work on more efficient and better ways to deal with this threat to our whale populations. One method that has worked well is to work with fisherman to design fishing gear, which have weak links so that they break easier when whales swim through them. It is a controversial issue between many parties, but hopefully we will see a decline in whale entanglements in the future.
You might think it’s easy to navigate a ship. Just point and drive, right? No. Navigation of a ship is a complex endeavor which requires skill and the use of many different technologies. Think about it. You need to consider wind, tides, currents, depth of water and other ships in the area. Luckily the Delaware II has a great deal of equipment and skilled operators to get our ship from point A to B.
So let’s dive into the art of navigation. First off you need to know where you are.
The Delaware II has a global positioning system, which is a satellite-based navigation system. It works something like this. The US government launched satellites up into orbit around our Earth. They constantly send out light wave signals with a time the message was sent, and the location of the signal at that time. A receiver on the ground needs to receive at least 4 of these signals, sometimes three will work, to get an accurate reading on where that receiver (you) is located. But you just don’t want to rely on one system, so the Delaware II has 2 back-up systems. The crew also utilizes a magnetic compass, and a Gyrocompass. As you know the magnetic compass points toward magnetic north (considering the declination of your area). However the Gyrocompass is an instrument that is mounted in a device so that it spins freely. When the device is moved in a different direction, such as ocean swells or turns, the gyroscope will always point to true North. A gyroscope spins about three axes of angular freedom due to its inherent properties and its being acted upon by the earth’s rotation and gravity. Control devices are applied to balance the forces so that the gyro seeks and continually aligns itself with the meridian and points to true north.
You also need to know what is going on down in the water. If the ocean floor gets shallow or the currents change this is going to affect the ship’s safety and or progress. The Delaware II gets this information through two navigation depth sounders. They emit sound waves out of the bottom of the boat and time how long it takes for the waves to get back. Remember our formulas during our energy units? Speed equals distance divided by time. Well we know the speed of sound in water at various temperatures (remember the speed changes with different mediums and the temperature), so you multiply the time (divided by 2) by the speed and you get the distance. Luckily the navigation depth sounder does all this math for you automatically and you get a picture on the screen showing the depth of the water below the ship.
The Delaware II has a large computer which uses software called Nobeltec. This displays the most recent charts, or as we call them maps, on the screen. These charts indicate all land and the depths of the water. Before leaving the navigators plot the course on the chart and this is what they use to steer the ship. Of course, safety is incredibly important so this course is also drawn out on paper charts in case the on-line computer goes down. I watched Ensign Junie Casson transferring this information and it isn’t easy. Knowing latitude and longitude are key as well as determining the degrees in which you want to travel. See that! Math and social studies really do come in handy! Junie is also responsible for keeping the ships charts up to date as information is constantly being acquired on the topography of the ocean floor.
You also need to know how the currents are moving in the water you are traveling through. Especially should the ship release equipment, such as nets or instruments. This is done with the Doppler speed log. It emits 3 sonic beams and the information is used to determine the speed and direction of the water in three different layers. Speed and direction of the water is affected by winds, rotation of the Earth (remember the Coriolis Effect – it affects the direction of the water as well as the air) and tides. Deeper layers tend to move more slowly because there is less energy transfer between layers as you go down.
Lastly we want to make sure that no other ships are getting too close, that we aren’t getting too close to certain objects or to fix ourselves upon a certain point. For this the ship has two different kinds of radar. One radar called x-band, has a higher frequency and shorter wavelength. The second radar is called s-band, and has a lower frequency and longer wavelength. Both are used to get the best accuracy with identifying objects.To avoid collision, The Delaware II uses an integrated ARPA (Automated Radar Plotting Aid) to quickly analyze trial maneuvers. Different courses and/or speeds are assessed and the calculated outcome in terms of a CPA (closest point of approach) is determined. Whenever possible at sea, one nautical mile CPA from all other traffic should be kept.
On my first blog I asked which of the following whales is the longest; sei, fin, humpback, right and minke. While most of you picked the humpback the fin whale is actually the longest.
Questions of the Day:
When you determine the time in our equation to determine the water’s depth you would need to divide it by two. Why?
In ancient times, ships didn’t have the equipment I just described to you. How did they navigate the ship?