From Stykkishólmur (Snaefellsnes) to Brjanslaekur (Westfjords) there is a ferry service. If you want to skip a part over land and want to see Iceland from the ocean, this is the perfect way to do it.
There is a stop at Flatey as well, so you can also stay there for the night. Check out the hotel I recommend there.
It is a really nice sail and you might even see some whales from the boat.