Today we did some CTD runs and built a dredge. The CTD runs were a little more complicated than previously, because they had to be done in many different locations. To do that in a kosher way, the CTD has to be pulled on board and redeployed at every stop. Since the process of capturing and relaunching these devices takes well over an hour, this would not be time efficient, so we didn't do it. We left the CTD 400 meters below the ocean, and dragged it around.  We didn't move very fast, only about half of a knot, but the concept is still sort of mind boggling.

We also put together a dredge. Dredging is the simplest way of collecting bottom samples. Basically, dredging involves dragging a metal bucket along the bottom of the ocean, in an attempt to get rocks into it. There's much more to it than that, but the basics are that it should be kept in reasonable condition.  The cable that we use to pull it can withstand around 20,000 pounds of pressure, and the cable is expensive, so we don't want to exceed that. The problem is that the dredge will get caught on things, because the rocks we are trying to pick up may jut up, get in the way or have deep fracture trapping the dredge.

Anyway, the dredge consists of a metal, bottomless box that picks up rocks, which are then deposited into a chain bag that hangs from the box. We had to make the chain bag. This is as hard as it sounds, and it is a lot of work. From the pictures you can see that it looks like interlinked and crisscrossing chains, which is pretty accurate. You start with chains dangling from the box, and then you mesh them together with repair links, chain links that have not been put together fully.

In total, we spent about 4 hours, with 6 people working nonstop making the chain bag alone. To get the chains attached to the box was another story all together. Today was pretty hot, and working outside in the sun left us wanting nothing more than to dive off of the fantail and go swimming for a few hours. The water was clear, and everything pointed directly to swimming, except for the rules.

Daniel Staudigel onboard the R/V Kilo Moana.