Matthias Kaßner - Around Müggelberge

counter-clockwise circumnavigation

29 km (18.0 miles)

13 hours, 7 minutes on 28 August 2020

Observed and documented by Ina Kassner




  • Name: Matthias Kaßner
  • Gender: male
  • Age on swim date: 52
  • Nationality: Germany
  • Resides: Berlin

Support Personnel

  • Jörg Büttner - crew / feeder
  • Eltjan Kranzusch - boat pilot
  • Ina Kassner - observer

Escort Vessels:

  • Linda - motor boat B-1540 V 4plus2 (Richtershorn/Schmöckwitz)
  • unnamed - sport motor boat B-4033 V (Richtershorn/Schmöckwitz)

Swim Parameters

  • Category: Solo, nonstop, unassisted.
  • Rules: MSF Rules of Marathon Swimming, without exception or modification.
  • Equipment used: Speedo Endurance brief, Zoggs Predator Flex goggles, one silicone swimming hat.

Route Definition

Counter-clockwise circumnavigation around the so called ‘Müggelberge’, starting and ending on a beach close to Schmöckwitz, going up 3,8k through lake Seddin, 2,6k through the Gosener Canal, 3,8k through river Müggelspree , 3,6k through lake Müggelsee, 4k through river Spree and finally 12,5k through river Dahme down to the beach at Schmöckwitz.

  • Body of Water: Lake Seddin, Gosener Canal, River Müggelspree, Lake Müggelsee, River Spree, River Dahme
  • Route Type: circumnavigation (counter-clockwise)
  • Start and Finish Location: Little beach in Schmöckwitz (52.375722, 13.661583)
  • Minimum Route Distance: 29 km (18.0 miles) (map)


No known previous swims of this route.

Swim Data

  • Start: 28 August 2020, 05:40:50 (Europe/Berlin, UTC2).
  • Finish: 28 August 2020, 18:47:50
  • Elapsed: 13 hours, 7 minutes.

Summary of Conditions

Feature Min Max
Water Temp (C) 19 21
Air Temp (C) 13 20
Wind (m/s) 2 5

GPS Track

Trackpoint frequency: 10 minutes. Download raw data (CSV).

Click to expand map.

Speed Plot

Observer Log

Download PDF


by Matthias Kaßner

I originally had a slot for Molokai in September 2020 but like many other swimmers I had to quit my plans due to Corona. And so I thought about an alternative swim without traveling and other uncertainties, which would be much easier to realize. After some research and discussions with friends I found a 30km lap through rivers, lakes and canals in Berlin, Köpenick. This swim has never been done before.

To prepare the swim we did three tours (me swimming, my wife and a friend kayaking beside me) and within these three tours we explored almost the whole route of the swim. We found a starting point located in Schmöckwitz at a small beach and defined the direction as counterclockwise due to a strong current in the Müggelspree. We also organized a boat and a pilot via a friend of a friend.

The swim itself was beautiful but had many obstacles for me. I got sick very early in the swim and it lasted until the end. I really had to dig deep to continue. After a few hours in the swim we had to deal with a rope in the propeller of the boat and a lost feeding bottle (there was no replacement on the boat). We had to deal with much boat traffic from ferries to sailing boats and motorboats. After three quarter of the swim our boat engine broke down and we had to organize a second boat to continue the swim. With the replacement boat (the crew had to switch the boats in the water and I just continued swimming) I finished the swim at the same place where it started 13 hours 7 minutes before.


Click to enlarge.