If you ask a leisure boater, the Finnish summer has been great. The weather in July-August has been phenomenal - though perhaps too hot or non-windy to some taste- but very welcome for most. Our longest trip was some two and a half weeks in the Turku archipelago which was the first trip with our daughter, and it went great (some photos can be found at: http://salamamatkat.tumblr.com/archive with comments in Finnish).
But an unpleasant phenomenon glooms the idyllic Baltic Sea: there has never been this much blue-green algae in the Finnish coast http://www.finlandtimes.fi/national/2014/07/22/8547/Decade’s-biggest-blue-green-algae-spread-in-Finnish-coast). This has practically nothing to do with my posting, which is about boats and their environmental impact, but anyhow made me again think the state of the much loved sea.
Blue green algae at the Baltic Sea (source: The Finnish Border Guard)
Should I have a bad conscience because I boat and, thus, pollute the Baltic Sea? It is quite evident that societies and industrial players are the biggest reason for the bad condition of the sea, but we should all do our share, right? But what is the environmental burden of my boating hobby?
I’ll simplify my assessment by leaving out the boat manufacturing impact (it’s already 40-years old, and will last another 40), dissolution of anti-fouling paint or other poisonous material, and possible disturbance we cause to sea animals. I’ll focus on energy and waste.
First, the boat burns a lot of diesel fuel, around 5 liters per hour. This summer we drove approximately 60 hours = 300 liters of diesel, which accounts for roughly 800kg of CO2. This is a lot, but it is pretty much all that is needed: the other primary energy source we use is propane (for gas stove and fridge), but the amount used during summer is around 4kg. We also consume electricity, but it is generated while running the diesel engine.
As for waste, we naturally produce household waste which is dumped to waste sorting stations from where, to my best understanding, they enter the national waste management system. Also waste that is produced by “biological means” is sorted: our boat has a septic tank and many guest harbors have a waste pumping station for emptying it. Most of this infrastructure is maintained by association called “Keep the Archipelago Tidy” . So, compared to me doing other things, the amount or disposal of waste remains the same.
Based on this (non-comprehensive, I admit) analysis, I consider the ecological footprint of our boating hobby quite moderate. The 800kg of CO2 compares to two people flying from Helsinki to Barcelona and back (1100kg), which would be a reasonable alternative for summer vacation activity. But for domestic traveling with a car, driving 1000km would produce significantly less: 150kg of CO2. So, it is all relative what can be considered as ecologically reasonable. This also applies for boating: I know some sailboats can drive less than 10 hours with the engine during summer (=negligible CO2), and I know boats that consume 50 liters of diesel per hour (=8000kg CO2 if driven 60 hours).