Came across a lovely little app a week on so ago called 'Blue Boat Log'. I had tried it over a year ago but it didn't fit our need or provide any additional features to the main Kevayling log book.
Now the author has been busy and produced an upgraded version of the app which is really good.
In essence it provides a track of your trip with date, distance and time data as well as an ability to add a story of your trip with photos. Embedding this into the Kevayling log it now means we can record all trips on the water in our boat or crewing someone else's.
Blue Boat Log - worth a look.