My father-in-law, Canon David Kanabahita, was a visionary teacher who helped many Ugandans fulfil their potential. Among his many achievements, he is remembered as the former head teacher of Hornby High School in Kabale, Uganda, which recently celebrated its centenary.

The junior school's current head teacher, Geoffrey Beinomugisha, says the school remembers David as a principled leader who nurtured teachers and students, advancing in particular education for the visually impaired and blind, whose needs are under-served in Uganda.

Today, Hornby primary school serves 280 students including 24 blind children. Of these 75 percent are classed as "needy," meaning they are orphans or come from families with limited means. 

Thanks to a centenary fund-raising drive, the school has installed a rain water harvesting tank to reduce the cost of piped water. It also has plans to give the school a face-lift and build a computer lab to start computing classes.

To support these efforts and in memory of David, I attempted a 7.5 mile swim across Ullswater in the Lake District. This was a huge challenge: more than double any distance I have ever swum and in challenging conditions.

Winds were battering Britain and the race start was delayed due to a squall. When I got into the lake I felt the cold immediately: it was was 14 degrees Celsius – way colder than I was anticipating. I decided to at least aim for half way, but for most of that time I was thinking either:

• I’m cold
• There is no way I can finish
• What is an acceptable distance to aim for that I can get out and not feel embarrassed?
• If I don’t finish, should I return the money to all the people who have sponsored me?
• I can’t wait for dinner.

I made it to the mid-point then convinced myself to try for another kilometre which would get me to my furthest distance in training. There, I decided to carry on until 9k, which is the distance I’d intended to train for. That, I decided, would be enough of an achievement to justify not having to return the sponsorship money.

But I’d entered a different part of the lake, where it was really choppy. I kept getting hit by my tow float and getting mouthfuls of water. It was also hard work, which had the advantage of taking my mind off the cold.

At the 9k mark, I asked a kayaker if conditions were likely to improve – he answered in the negative. But I’d got so far it seemed silly to give up. That didn’t mean it was easy. To reach the finish line we had to cross the lake, and that last part was really, really choppy.

Somehow I made it in five hours and 21 minutes, which amazingly given my lack of experience and time to train meant I came third in my (admittedly small) age category. I've learnt a lot from this race, not least that you can sometimes achieve things which seem impossible. More importantly, at the time of writing I’d raised £1,797 for the students of Hornby.