Reconciling a passage planned on paper with one made on a tablet can be a challenging but useful exercise for a rusty skipper
Back then, we’d used GPS and paper charts so I was thrilled at the prospect of using my brand new Raymarine plotter with AIS, and Navionics on my tablet.
However, before I contemplated getting to grips with electronic plotting, I wanted to be sure I could still adequately read a paper chart!
I ordered a brand new set of Imray charts. Oh, the smell of new charts… it’s worth having them for that alone!
Speaking to the harbourmaster, marina staff or other boat owners is a great way to start planning a trip. Local knowledge is priceless, and after a few chats with Chichester boaters, it became clear that Lymington or Yarmouth would both be nice places to overnight, but the biggest challenge would be getting the west-going tide through the Solent.
“That will make or break your voyage,” said Matthew Leigh, deputy manager at Premier’s Chichester Marina. “Fighting the tide on a small boat can cost you hours; heading out of the Needles to Poole, that’s the element I’d look at, as well as the bar.”
Matt also reminded me to check the winter opening hours for Poole bridge.
“It can be an awful frustration at the end of a long voyage to arrive and find you have to wait an hour or more,” he warned.
Checking the pilot book
The next thing I did was read the chapter on The Solent and Approaches in Tom Cunliffe’s Shell Channel Pilot. Wry nuggets such as ‘The Bramble [bank] has been placed by a deity with a sense of humour smack in the middle of the Solent’ and ‘Best to stay north of [Gurnard Ledge] green lit buoy as though you were a tanker,’ certainly stick in your mind!
Tom also advised to be wary of Chichester harbour entrance. ‘While tranquil on a reasonable day, Chichester Bar takes a toll nearly every year from amongst those foolish enough to chance their luck at the wrong time.’ The ‘wrong time’ being after half-ebb in a strong onshore wind.
Now for the detailed planning. The first thing I did was work out the total distance, our average boat speed, and a rough time. Using Imray’s Isle of Wight chart, and a pair of dividers, I measured 2 miles to get out of Chichester harbour (though local knowledge suggested allowing an hour to account for the speed limits, and marina lock), 29 miles roughly from Chichester Bar to Christchurch Bay (opposite Barton on Sea), I then switched to C4, Needles Channel to Bill of Portland, and measured a further 12 miles to Poole Harbour entrance, and from there 4 miles to Cobbs Quay marina – 47 miles in all.
I checked this against the distance tables in the Almanac. Chichester Bar to Poole Harbour entrance was 42 miles – I was just a mile out on that section. So, 48 miles altogether.
Assuming an average cruising speed of 5 knots (maximum speed for a Maxi 84 is stated as 7 knots), and tides either cancelling each other out, or – if we plan right – adding speed over the ground (SOG), this would take 11 hours.
With maximum daylight hours in November being 9.4, and this being my first voyage in a long time, I didn’t want to do it all in one go. My options for an overnight stay were Lymington or Yarmouth, Isle of Wight. Both were approximately half-way, and lovely villages full of old pubs. I
n fact, I’d stayed at Yarmouth a few times before when crewing for other skippers – including my dad on our GK24 Gallant Knight – and very much liked the idea of going back.
The voyage therefore would be 26 miles on Day 1 (Chichester Marina to Yarmouth) and 29 miles on Day 2 (Yarmouth to Cobbs Quay, Poole Harbour). Allowing five to six hours’ sailing each day seemed feasible.
Finding the window
Originally, we’d planned to do the voyage on 27 October. However, the rewire wasn’t finished, and there was just no way we could leave without a working engine or nav lights.
We wanted to get the west-going tide through the Solent for as long as possible. Though I ordered a set of Admiralty Tidal Stream Atlases, I didn’t really need them as everything was already in the PBO Small Craft Almanac 2022. However, it was nice to have them in a quick-reference A4 book.
The tides were favourable from 1 hour before HW Portsmouth to (once past Calshot) 4 hours after HW. Wednesday 10 November was the earliest we could do but HW was either 0323 or 1539, which was either too early or too late to be leaving Chichester.
The following week looked better so we opted for 15 and 16 November, with high tide at Chichester being 0919 (4.4m corrected to chart datum).
Assuming it would take an hour to get to the bar, and then another hour to reach the East Solent, I aimed to leave as close to 7am as possible. It would be nice to catch the west-going tide by 9am (HW-1), but not essential as we were on neap tides, and this would only give us an additional half a knot at most, peaking at 1.9 knots in the Solent.
A more realistic time to depart seemed 8am, especially given our 2-hour drive from Bournemouth, and the sun would be up then. All being well, we’d be in Yarmouth just after lunch.
Planning for the following day was more straightforward, and the favourable tides would allow us a leisurely breakfast before departure from Yarmouth to Poole.
Though arriving in Poole at low water, there’d be sufficient water if we stuck to the channel, the mitigating factor being that the bridge winter opening times were every two hours, so we couldn’t miss our slot!
We also had to drop off my husband on Poole Quay by 2pm to do the school-run, but I had after-school childcare on standby.
Downloading electronic charts
Having plotted the route on paper charts and sketched some pilotage charts in my notebook, I decided to compare my route to one automatically calculated on my electronic charts.
Unfortunately, I couldn’t do this on Raymarine’s Lighthouse charts, as you need to insert the SD card into the chartplotter itself (which was obviously installed on the boat).
Inside my Imray chart pack was a foil scratch-card type bar, offering a ‘free mobile download’ and a QR code taking me to the app I could download on my phone.
Unfortunately, though, this wasn’t intuitive. The app instructions were not well organised. Try as I might, I couldn’t find out how to mark a route. As I was short on time, I gave up and instead turned to Navionics, which was brilliant. I aim to give the Imray app a try another time.
I downloaded Navionics (for which there are constant updates) to my tablet and found it very easy to plot a course both manually and automatically. You simply enter your boat’s draught, circle your start and finish waypoints by pressing down your finger, and bingo, it does it all for you, correctly following the buoyage.
I also requested tidal data, and it gave me actual tidal heights (as opposed to chart datum) at any given time of the day, which I scrolled through with a swipe of the finger. Wow; several hours’ work on paper condensed to 5 minutes on chartplotting software!
Note, though, that the route Navionics gave us was over-cautious. In reality, had we followed this course, we’d have added hours to the voyage by taking unnecessarily long routes around lateral marks, when there was actually sufficient water to sail the rhumb line. So having sufficient navigation skills (albeit rusty) to plot on paper, or manually programme an electronic chart, was still very useful.
Transferring from wifi device to plotter
The problem with tablets is that they’re not daylight viewable, waterproof, rugged or have enough battery power for prolonged cruising, so while it was useful to plan a route on a tablet, once actually aboard we could hardly see it! Instead we re-programmed the route on Raymarine Lighthouse charts, which were excellent.
That said, the good news is that Navionics actually produce an SD card you can use in Raymarine’s plotters, meaning you can still plan a route on a tablet or a phone, and then sync it to your onboard plotter via the Navionics Boating app. For any lengthy passages, transferring saved routes from a tablet to an onboard plotter seems like a far better idea than having to do it all when you get to the boat.
Activating the SD card for the Raymarine plotter
While it was easy to operate Raymarine’s Lighthouse charts on board, what I didn’t anticipate was the faff required to actually get the micro SD card working for the very first time. I was given a blank SD card with a voucher code to download charts from the Charts Manager app.
You can download them either straight to the chartplotter (but being in Chichester on the boat this wasn’t possible) or your tablet or computer. The computer option wouldn’t work, so I had to steal back my tablet from the kids.
By the time I charged the tablet, unpinned all the football scores, saved and deleted the videos of the fox, changed the parental settings and downloaded the app, I’d already wasted an hour. Then there wasn’t enough memory to download the charts. Then an error message ‘database disk image is malformed’.
Then, a warning that my account expires in a month, even though I’d only just opened it… and after all that, no digital charts. Eventually, after a call to Raymarine, I got the SD card working, but I’m glad I didn’t leave it until I got to the boat, where I’d be reliant on marina wifi. Two hours spent downloading charts would not be a great way to start a voyage!
Ready to go
I checked my safety equipment – items such as fire extinguishers, throwing lines and buoys – and checked my lifejackets. I decided to get rid of my manual-only inflation lifejacket; the last thing I want to be doing if I fall overboard is scrabbling around for a toggle.
I still had out-of-date flares to replace but as I was yet undecided as to whether to replace these with pyrotechnics or lasers, my crew Gilbert suggested he bring his grab-bag, complete with EPIRB and laser flares, as well as a liferaft.
This sounded like a good option because I wanted to do some more research before spending more money. We had the right equipment for the voyage, and that was fine for now.
At last, the provisional date was set, the boat ready, the passage planned, and the crew booked. I was happy I’d ticked off everything except for the weather… and for that, I was just going to have to cross my fingers and hope!
My passage planning checklist
- Circle potential dates for the trip and check crew availability
- Decide on overnight destination and check availability of berth
- Read pilot book and/or almanac for passage advice
- Check favourable tides, currents and weather forecast in relation to intended passage
- Set out waypoints on the chart (electronic or paper)
- Add landmarks, bearings and course-to-steer
- Note VHF channels for ports and bridge control
- Estimate duration of passage
- Look at daylight hours – am I happy to arrive in the dark?
- Look at tidal gates and restrictions (ie harbour bar, headlands, bridges and locks
- Enter desired time to complete tidal gates and work backwards to find departure time
- Choose ports of refuge/Plan B if conditions deteriorate
- Sketch a series of pilotage charts in notebook
- Check tablet is charged, routes downloaded, charts are updated and chartplotter SD card working
Thanks to our Project Boat Supporters
Dell Quay Marine, Osculati, Raymarine, Shakespeare Marine, TruDesign, Screwfix, Coleman Marine Insurance, MDL Marinas, Premier Marinas, seajet, Marine & Industrial, Clean to Gleam, West System, Farécla, Navigators Marine, RYA, Aqua Marine, Ecobat, Victron Energy, Scanstrut, T Sails and XP Rigging.