by Michael Walther, Fiber Technician | 22 Jan 2026
In the middle of winter, we got an emergency call.
A fiber cable that had been damaged in the fall was still working, but barely. Once the temperatures dropped and the ground froze, the signal quality started to deteriorate fast. We had planned to deal with it in spring – but this time, waiting was no longer an option.
The challenge was simple and brutal:
Only one duct available. And inside it – the damaged cable.
So the decision was made: replace the existing 192-fiber micro cable with a new one of the same type, using water and double floating over a distance of approximately 4 km.
The main reason I chose water this time was the distance.
From experience, the probability of reaching long distances increases significantly when floating with water – and even more so when double floating. In cold conditions, friction is higher, materials are stiffer, and margins are smaller. Water simply gives you more control and more range.
We rigged the equipment and carefully positioned the existing cable in the Y-block before tightening the lid. Once everything was aligned and checked, we started the installation.
Because we were double floating, we ran at a slightly higher pressure than usual.
The first 2,000 meters went smoothly.
After that, the movement became uneven and jerky – a classic sign that something isn’t perfect, often pointing to small leakages somewhere in the system.
At 3,000 meters, the water was gone. All 8,000 liters.
We had to stop.
In winter conditions, standing water inside a duct is a serious risk. Leave it too long and it will freeze – fast. So we connected our 5 m³ compressor and ran it at low pressure, just enough to keep the water moving.
After about 1.5 hours, the flushing truck returned.
By then, we had pushed out some of the water using air, which meant it took a while to refill the duct and stabilize the pressure again. But eventually, the system balanced out – and the cable started moving.
Again.
At 3,900 meters, the cable reached its destination. Job done.
Splicing of the new cable started immediately. The damaged cable will be removed later – that part can wait until spring 😉
If you plan to float cable in winter, a few things really matter:
Winter installations are never comfortable. But with the right setup, the right method, and a bit of patience – they are absolutely doable.
And sometimes, they simply have to be.
