Day 7 - 5 miles - 86 to go

Cookham to Marlow

A perfect Solar Day and this should have put fresh life in the main batteries. By proceeding on one engine I have been able to rest one battery completely and this may be the best way to proceed. Ian Rutter was able to lend me a very simple device (the 'clip on' ammeter) for measuring the current (aka amps) being used by the electric motors. So more tests today when I have two engines available.

Wonderful secure mooring at Temple Lock courtesy of Andrew and Cereze Gay, which has enabled me to have my first proper bed for a week; such joy in simple pleasures!

I may have to run the gauntlet of Henley this afternoon, with the press office being ready to announce my mission. I am hoping to sneak a mooring for the night - optimistic?

Technical Notes - propeller heads only!

Here is a picture of the batteries! The key to successful electric boating is have decent 'deep-cycle' batteries of the type used in fork-lift trucks; these are different from a car battery, which is designed for high starting loads and then to be kept at full charge most of the time. The basic measure of the capacity of a battery is the ampere-hour, which is the number of amps it will provide per hour from full until empty. My batteries are rated at 225 ampere hours which means approximately 20 amps for 10 hours as you can never get the last bit out! At the speed I am trying to maintain - a humble 2 miles per hour actual speed across the ground against wind and current - I could only guarantee 15 hours continuous running. The charging rate from the solar panels is on average about 7 amps on a decent day. The maths is not friendly! But of course the panels are charging all the time, even when cruising.