Passage planning is a pretty individual thing, so I'm not sure how interesting my way of doing it will be to anyone.
I do sometimes "just go" -- if settled weather
, non-tidal waters, and familiar route
, little is needed. Calling ahead for a berth, or maybe not even that, might be the extent of planning in these limited circumstances.
In tidal waters, however, my passage planning might take hours -- for a complicated Channel crossing, for example.
For a cross-Channel to the Channel Islands, for example, I would do the following:
1. Tidal streams out of the Solent -- what's the window? When is the optimal time (to take advantage of strong favorable streams)?
2. Is there an optimal crossing time? Neptune+ will calculate this based on various scenarios of average boat
speed -- the differences can be profound even though most of the streams are perpendicular to your path.
3. Is there a tidal gate at the other end? The Alderney Race
, for example? Can you be sure of making it before the tide turns? If somethings happens and you can't, can you bug out to Cherbourg, or some other place? Is there a tidal height limitation at the other end -- a port you can't get into at low tide? Locks maybe? What do you do if you miss your window -- is there someplace to anchor
-- what is the risk of stronger weather than you are willing to be out in? Is there risk of strong weather against tide at the other end? Is there a bar to get across? What are your contingency plans if the weather turns out worse than predicted? Ports
of refuge along the way? I make a thorough catalogue of these with all their characteristics. My personal limits for planning are F8 as long as the wind
is not ahead of the beam and subject to wind
over tide situations. I try hard to avoid anything over F6 if I have to go upwind. If the wind is predicted to be above these levels, I will usually not go if that is an option. If it gets over these levels while underway, I will consider aborting to a port of refuge if one is available, unless I'm having a great downhill run in something stronger, and the sea state is manageable. I really don't care about rain and usually don't even check this. I might have a look at visibility.
5. Calculation of a course to steer across tidal waters. I used to do this by hand; nowadays I use Neptune+. Usually in three variants for various scenarios of boat
speed -- 7, 8, and 9 knots if there's a nice sailing wind and my bottom is clean. Having this worked out thoroughly in advance makes it easy to adjust your CTS as you go along.
6. Hazards, headlands, etc. A close analysis, using paper charts
, of the predicted course and all hazards along the way. I make notes of these, try to memorize them, and often put waypoints into my plotter with a skull & crossbones icon, to remind me at the helm
where hazards are. At the same time, I mark on the chart where I expect to be hour by hour, which makes it much easier to be oriented as to my progress, and much easier to figure out how to deal with deviations from plan. These marks also make it easy to check how well your CTS is working out compared to plan -- also you can compare XTE from your instruments to your distance from the rhumb line, hour by hour. I do rely on my plotter for avoiding hazards, and no longer calculate clearing bearings in advance, just for the really freak chance that all my plotters go out -- waste of time IMHO. I always have paper charts
, and if every electronic device on the boat were to be taken out by lightning
, for example, I would just heave to and work
out clearing bearings.
7. Watches and assigned roles for the crew.
8. Plan meals
9. Harbor pilotage at destination
. I study the charts and try to memorize the layout, channels, landmarks and main features of the destination
harbor -- especially if its a new harbor for me, and doubly especially if entering at night. Experience has taught me that this is extremely important. If you don't do your homework you run a great risk of being disoriented when you arrive, which can be very dangerous.
10. And, obviously -- plan the route
, with waypoints to get you past headlands and through hazards, etc. Put the waypoints in the plotter. Sometimes I construct a route out of them on the plotter, but often not. Calculate the distances for planning time.
That's mostly it on my boat. Most of the effort, in tidal waters, goes to getting the timing right.
On a coastwise passage in tidal waters, it is somewhat simpler. If the passage can be done in one tide (typically 50 or 60 miles), then the main thing is to work
out the optimum departure time, to make sure you don't run out of tide. And to be sure that your arrival time is ok for crossing entrance bars and getting into harbors.
I guess the main difference between my approach and Jackdale's is I do little or nothing which is solved
with the plotter -- I don't calculate bearings to landmarks, lights, etc., since I get this information at a glance from the plotter. I think these exercises can be useful, and certainly the skills are, but I prefer not to spend too much time on such things since they are a distraction from doing the things which the plotter can't do. I have two different fully independent backups to my main plotter and consider electronic plotting to be mission-critical. If everything electronic goes up in smoke and I lose all my backups, then I will heave to and do all of the chartwork and manual calculations, but otherwise I will not spend time on this.