The Naiad Voyages

Mark Austen

2021.10.12 - When to Depart from Home and Arrive Back Home

One of the problems I'm going to encounter. once Naiad is ensconced in a mud-berth at Brightlingsea (I know, I don't have one yet but I'm being optimistic for a change) is when to leave home on a Friday afternoon to get to Naiad when she is afloat and when to depart from the berth on a Sunday. It's not an easy task as it can get quite complex.

For example, The drive from home takes around 2 hours. The boat is accessible 3 hours before High Water (HW) to 3 hours after HW. So, if I leave how on a Friday at 16:00, as soon as I finish work, at what time should HW be in order for me to be able to get aboard?

The 2 hour drive means that I'd arrive at 18:00 and that needs to be within 3 hours of HW so the time of HW needs to be between 15:00 and 21:00. I can use this information and a set of tide tables to find all the Fridays that have a HW between these two times also taking into account the availability of the water taxi.

Now, the return journey. I can't get ashore before 08:00 as the water taxi doesn't start before then, so the earliest that HW needs to be to account for this is 05:00. Likewise, the water taxi stops running around 21:00 during the season, 18:00 during November and 16:00 for December through to the end of March. Given that the drive home takes 2 hours and I really do not want to be arriving how later that 21:00, I'll take the time to leave to be 19:00 at the very latest. That means that the earliest HW needs to be to account for this is 16:00. So, I need to identify Sundays with HW times between 05:00 and 16:00.

Looking at the two sets of result, I can see the weekends when HW on Friday and HW on Sunday are suitable.

Well, that's not too difficult, but what if I now want to leave home on Friday earlier? Or perhaps I want a list of the Fridays that are not a match but the Sundays are and what time leaving home would make the Fridays a match.

I have to do the calculations over and over again and I'm not really interested in doing this repeatedly. I need a better way.

Stay tuned.