Logo of the Physikalisch-Technische Bundesanstalt
Symbolbild "News"


1 May 2023


Position, 1.5.2023Current position while writing (diamond shape). The circles are the positions at previous blog posts, the black line is roughly the route we took (base map from Opens external link in new windowggplot2).

Initially, I wanted to write about something different today but then this topic just stuck into my head. So, you’ll have to wait a bit o learn about what I packed for this cruise and today I’ll tell you about rhythms that govern life on board.

My safety boots (and many other shoes) squeak when walking on the plastic floors here. Somehow you actually get used to that and it has its advantages. Since the corridors are quite narrow it is helpful to hear when someone else is coming around a corner.

Waves are probably the first thing that comes to mind when thinking about ships and the sea. Up to now we are really lucky, and the ship is only gently rolling. Kind of gently rocking us to sleep..

I had my phone measure our tilt to the side. You can nicely see the waves and that our movement is not completely regular. (Credit: Rieke Schäfer)

Interestingly, there are often times when you feel the waves just slightly and then one wave is much more pronounced. Most of the time it is a rolling movement from to the sides less to front or back.

Food is, of course, very important, otherwise we couldn’t do anything. We are cared for very well here and the mealtimes structure the day.

  • 7 to 8: breakfast
  • 10 to 10.15: coffee break
  • 11.30 to 12.30: lunch
  • 15 to 15.15: coffee break with cake
  • 17.30 to 18.30 Uhr: dinner


coffee break
Coffee break (in my case tea break) with a view (photo: Rieke Schäfer)

These set times allow for a daily rhythm into which other things can be integrated. For example, I take one discrete sample before breakfast and the other one after dinner. For others who take discrete samples more often, some sample times get nicknamed as, e.g., “after cake sample” when they plan who is taking samples when.

CTD stations
Not as regular as the mealtimes but at least as much governing timings are the times at which the CTD stations are. At station we stay at the same spot several hours and both CTDs are moved through the water column (more details about this in the future). Now, we usually have about 20 hours sailing time between stations which is much easier to manage than the shorter times at the beginning. This is especially true for those who have to spend hours in the lab directly after sampling to fixate their samples. However, 20 hours sailing time and several hours on station also mean that the station times change every day. We are all trying to get enough sleep in between, the timing depending on our jobs related to the CTD.

The CTD stations we already did
The CTD stations we already did (orange dots). As you can see, the stations were much closer at the beginning and are now equally spaced directly on the equator. (idea, installation and picture: Andreas Schürmann)

The food does not only provide daily but also weekly repeating patterns. While the CTDs are the same every day (at different times and with somewhat changing samples), there are weekly repeating themes for the food. For example, Friday is, very traditional, fish day. Saturdays there is a soup or stew and on Sunday morning we get white worst and brezeln.

These themes give at least some structure and feeling for the week going by. For all other things, the days tend to blend into each other and it’s not easy to tell which day it is.

For all that join cruises regularly, these structure the year into different parts. Of course, this is especially true for the crew but also some of the scientists go on several cruises per year. This cruise with 50 days on sea is, however, unusually long. Most cruises are shorter.

With every cruise the composition of people on board and the research focus changes. If the ship could tell us what’s happening in its life it surely would have many tales to tell of cruises with completely different research questions which then in turn governed the life on board.

Die Gruppe
Most of the scientific team on the observer’s deck (Picture: Till Müller)


PTB doctoral student Opens local program for sending emailRieke Schäfer is blogging here directly from the RV "Sonne" on her way west from South America across the Pacific Ocean.