Practical advice for all sailors. Tom Cunliffe has sailed tens of thousands of miles all over the world and has been a Yachtmaster Examiner since 1978

I am writing these tips on board on the River Dart waiting for a break in bad weather to sail east. I must arrive at Portland Bill at the right time and by Sod’s Law this comes either soon after dark (not nice) or around lunchtime (better, but not popular as it means leaving at 0500).

I’ve been stuck for a while so I’ve been expecting the tide to advance at the usual 40-45 minutes per day. Not a bit of it. It’s crawling ahead at 30 minutes only. Why? Because I’m on spring tides. So far as I know, the rule is not set in stone, but springs often advance more slowly than the average, leaving friendly old neaps to take up the slack. Looks like an early start tomorrow!