Martyn Webster - Length of the Bodensee

Bregenz (AT) to Bodman (DE)

63.4 km (39.4 miles)

25 hours, 40 minutes on 15-16 September 2023

Observed and documented by Alex Nikitenko, Flurin Cavizel, Patrick Boche

Oldest to swim length of Bodensee.



  • Name: Martyn Webster
  • Gender: male
  • Age on swim date: 56
  • Nationality: United Kingdom
  • Resides: Rapperswil, Switzerland

Support Personnel


Alex Nikitenko
Support crew for Sri Chinmoy Zurich Marathon Swim
Pilot for Zurichsee swims in 2021 and 2022

Flurin Cavizel
Open water swimmer. Obersee in 2023. First-aid certified, lifeguard certified.

Patrick Boche
Race director, Bodensee Open Water.

Escort Vessel

Swim Parameters

  • Category: Solo, nonstop, unassisted.
  • Rules: MSF Rules of Marathon Swimming, without exception or modification.
  • Equipment used: Textile swimsuit (Funky trunks briefs), silicone cap, goggles (Swans SRX tinted and clear prescription), Timex watch.

Route Definition

  • Body of Water: Bodensee (Lake Constance)
  • Route Type: one-way
  • Start Location: Bregenz Harbour Beach (47.508126, 9.749987)
  • Finish Location: Bodman Strandbad (47.805281, 9.030521)
  • Minimum Route Distance: 63.4 km (39.4 miles) (map)


Three previous swims of this route, by Christof Wandratsch (2013), Bruno Baumgartner (2013), and Hamza Bakircioglu (2016).

Swim Data

  • Start: 15 September 2023, 19:25:00 (Central European Time, Europe/Berlin, UTC2).
  • Finish: 16 September 2023, 21:05:01
  • Elapsed: 25 hours, 40 minutes, 1 seconds.

Summary of Conditions

Feature Min Max
Water Temp (C) 21.2 23.3
Air Temp (C) 16.4 29.0
Wind (Beaufort) 0 2

GPS Track

Trackpoint frequency: 30 minutes. Download raw data (CSV).

Click to expand map.

Speed Plot

Nutrition: See observer log.

Observer Log

Download PDF

Swimmer Statement

by Martyn Webster

What inspired you to do this swim?

Lake Constance/Bodensee is a local lake for me. As the crow flies it is around 85km away. I love this lake and go with my wife to Konstanz and Meersburg regularly.

Over the last few years, I have seen a lot of 14km swim and 35km swims completed with Bodenseequerung organisation, but not many longitudinal swims. There have been few attempts, but all have been unsuccessful for the last 7 years.

The attraction for me was 3-fold:

  1. to do a difficult swim to push my boundaries
  2. to be the first British swimmer to complete a swim
  3. to be the first to do complete the swim in the opposite direction to those done before

Describe how you planned for the swim.

I have been thinking about completing a big swim for a few years. I have completed many 30-35km swims in the last year and seem to have energy left at the end of these swims – always. However, what I have learned in preparation for such swims is that to be successful on these longer swims you need a big window to be able to get the right conditions. So, at minimum a 2 days good weather within a 2-week window.

This year I decided to look for a swim 1) I could organize myself 2) something I could do from home that didn’t involve me committing money I might lose and 3) a swim I could have flexibility of dates on towards the end of the swim season.

I saw an advertisement on Facebook from Bodensee Open Water Company stating they were offering longer supported swims. So, I decided to contact them and see if they were interested in maybe supporting me with my flexible demands.

I met Patrick Boche, who runs this company back in January this year and we immediately hit it off and agreed we would look at September as the month and sometime around week 38/39.

Over the year we kept in touch and shared thoughts and met once more when I swam one of Patrick’s organized 10km events in June.

My plan for 2023 was to have 3 step-up swims. Starting with Lake Lugano (30km) in June, Flathead Lake (45km) in Montana in July, Jersey (54km) in August and finish all being well with Lake Constance/Bodensee (64km) in September.

Things didn’t go to plan though. I went to Lugano in June and was hit by thunder and lightning storms and didn’t get in the water. So, with some trepidation I went to the US to swim Flathead in July…not feeling prepared. However, we picked the best day in the week, and it all went perfectly. I came away from the US with renewed confidence. Two weeks later I was to go to Jersey. Then my mum got sick the week before and then passed away the week I had planned to swim. My world was rocked, my motivation was at an all-time low and I did not know what to do. Things got worse - I came back home and immediately got COVID. This was the second time. First time I had absolutely no symptoms, this time it completely knocked me out for a week and then I had a further week of feeling urgh!

However, I badly wanted to finish this year on a high. I firmly believe that this game is 80% mental. I had done all the training early on. Even if August was a complete disaster! I started back in the water mid-August just swimming 3km then 5km then 12km over the 3 weeks. By the time I got into September I was feeling back to my normal self, so decided to go for it! One for my mum!

I contacted Patrick. He had been watching the lake for months looking at the currents. This lake is very complex with the centre of the lake sometimes having swirling vortexes that need to be navigated and with the current directions in parts changing all the time.

We agreed on 2 potential windows - a shorter window in wk. 38 and longer window in wk. 39, when I had fewer work commitments.

At the start of wk38 Patrick contacted me and asked if I could come now. The weather and current flows looked perfect. Unfortunately, I couldn’t go earlier due to work commitments, but could 2 days later. We agreed to go for it rather than wait for another week and potentially have much worse weather. Then Patrick confirmed the boats and his crew, and I scrambled around to arrange my support group for additional helpers.

I worked the day of the swim until about 3pm and picked up 2 of the team on the way to the start @ 7pm.

How did the swim go, generally? Did you face any unanticipated challenges?

The swim went well. Normally I worry about the wind, but the wind was pretty much Bft 1 all the way and the temperature perfect at 21/22degC. What I didn’t realize was the significant effect the changing currents would have.

I started swimming at 7:25pm and by 8pm we were in the dark. The sun went down, and it was beautiful, the stars lit the sky. I could see Landau ahead @ 5km lit up like a Christmas tree. So, I just settled into my routine and focused on my stroke and breathing. Normally this is where I need to settle my mind and lock away those negative thoughts in the back of my head. This happened quickly, and I was swimming well for 20km or so.

Feeding went according to plan – all good, and I seemed to be averaging around 3.2km/hr.

Then when we got to 2 vortices around 20km, and my pace slowed to around 2.5 km/hr as the current pushed me back and from side to side. Once I got to 40km the current got even stronger and my pace dropped to about 2.2km for the remainder of the swim

My team were calling out and writing on a white board showing every 1km achieved and at one point I did ask ‘What is my stroke rate’ and they confirmed my stroke rate was constant 53/54 spm, so I knew there was a current pushing me back. I think after 45km I just accepted that this was going to be a grind to the end.

On top of this, the sun didn’t really raise its head until midday. Although it was light at 7am, we had fog so I really didn’t get that lift you get when you see the sun rise.

Based on my Flathead Lake pace and normal ‘all day’ pace I would finish in around 22-23hr, but once I got to 50 km, I knew it was going to be a 25-26 hr. swim. Ok I thought …. At least another landmark swim in passing 24hrs! . Adding an extra 2 or 3 hr. meant I was going to finish in the dark, not in my plan. Fortunately, it was only an hour or so and I had the lights of Bodman to guide me. As I approached the Strandbad I kept thinking I was going to swim into a post or a pontoon. Fortunately, my team were able to guide me safely from the motorboat and my wife and reporter Rainer were on the shore with flashlights showing the way.

The water was shallow at the end, and I had to get on hands and knees to get out. Once I had cleared the water I stood. I felt so much relief to have finished this. But I felt dizzy and sick and although I tried to pose for photos and questions I couldn’t for more than a minute. I needed to lie down with my feet up before I passed out. I have never felt so sick after a swim but then never swam for more than 14 hr. before. So, new territory!

30 mins later, with warm clothes on, warm drink inside I was starting to feel semi ok. I just wanted to go home and go to bed. Fortunately, that was a 2hr drive and I could crash in the back of my wife’s car.


Click to enlarge.