So you’ve made your pilotage plan – now I’m going to explain some skills and drills which will help you to execute your plan and hopefully keep you out of trouble, writes Sticky Stapylton.

The essentials of pilotage are keeping your plan simple, making the best use of all crew on board and, wherever possible, using transits, clearing bearings and soundings to help you know where you are and perhaps, more importantly, know where you are not!

Your GPS is a useful tool of course, but bear in mind that electronics are not failsafe.

1. Making use of depths and contours

Pilotage tip: Two approaches: the red course for good visibility and the green for fog

The wise navigator will always assign a member of the crew to keep an eye on the echo sounder, and if you are not sure how your echo sounder is set up you must make a simple check.

Find out where the transducer is on the boat, and drop the lead line at a point from the deck that lines up with the transducer position.

Note your lead line reading and compare it to that of the echo sounder.

If there is a serious discrepancy I would reset the echo sounder to show the depth of water at the waterline – and it’ll be helpful to know how far below the waterline the transducer is fixed.

If you do this there is no need to calculate from your tidal graph workings, because you will have a figure which is the rise of tide above chart datum: all you have to do is add this figure to the depth indicated on the chart.

Have a look at the chart. The skipper has planned a simple approach (red course) in good visibility by shaping a course for the fairway marker from which he would pilot his boat up West Reach to an anchorage.

If there is fog, and assuming that Haire Sound is not a busy channel with large vessels transiting, the skipper has planned an arrival to make use of the contours to find his way in (green course).

The essential here is to plan on being well uptide of the entrance: in this situation, we have a west-setting tide.

The nature of the seabed does make life easy in that the contours follow in a steady direction, but the skipper will have to reduce the depths to soundings so that the echo sounder will approximate to the actual depth at the time of arrival.

He will also need a good idea of the strength of the tide taking him down to the west so that he does not overshoot the fairway marker, which inconveniently has no bell, siren, bellows or gong.

2. Keep within the lines

Pilotage tip: Select two contour lines and ensure your helm keeps within these limits

An alternative way of piloting into a river entrance, again having calculated the rate, direction and rise of tide, is to select two contour lines and ensure your helm keeps within these limits.

With this system of pilotage, I work from the chart table, and if there is not a log repeater down below, I get the crew to call out all changes of 10° or more and the log reading every half cable or so.

Taking into account the strength of the tide, I mark up my position at each call, assuming I have a large-scale chart.

You do not want to be in a hurry, and a speed through the water of three knots or so should mean that you can keep a reasonably accurate plot.

The problem is that high and low pressure can make a difference to your speed over the ground: the tidal stream atlas’ speed predictions can never be dead accurate so you do have to be flexible and make use of all your senses to help find the mark or entrance you are aiming for.

By telling the helm to keep between the 5m and 20m contour lines (corrected with a rise of tide of 2.3m) and following the courses marked in red you will have a good chance of finding the fairway buoy.

If you fail to locate this mark you will need to think again.

3. Transits

A transit occurs when you and two fixed reference points form a straight line.

This is a position line which can be plotted on your chart: the intersection of two position lines gives you a known position or fix.

The ideal is to have the further of your two fixed points within three miles or so because if it is too far away you will have difficulty in getting an accurate position line.

Here, I have taken a transit between two navigational marks, a fairway mark and a green lateral buoy on 244°(M) and a transit between the radio mast on the hill and the left-hand edge (LHE) of Pigeon Island on 206°(M)

4. Keeping an eye on the wind and tide

Ideally,  you will have someone experienced on the helm when piloting, and this switched-on sailor will notice quickly if the tide is setting the boat off course, even if you have been distracted and hadn’t noticed yourself.

The important drill here is to make sure that, if you give the helmsman a mark to steer for, you give him a heading at the same time.

You need to give instructions that if the compass reading when the boat is pointing at the mark changes, the helmsman must place the mark on the down tide side of the boat, ie with the bow pointing uptide.

In this illustration the bearing to the mark at the turning point is, say, 110°(M), and if the helm just points the bow at the mark, with a strong tide, the boat could well be set into danger.

5. Leading lines or lights

As chartered, above, as seen from a boat, below

When making use of leading lines or lights, it is sometimes easy to turn in the wrong direction to get your boat back onto the correct line.

The way I remember which way to turn to get myself on the line is to look at the two marks and turn in the direction the nearer mark is offset in relation to the one further away.

As chartered, above, as seen from a boat, below

This will bring your two marks or lights back into line.

6. Circles of uncertainty

If sailing off the wind, there’s no leeway and neap tides: radius of circle of uncertainty = 5% of distance travelled since last reliable fix

In some circumstances, it is prudent to work on a ‘circle of uncertainty’.

As a budding Yachtmaster, I was encouraged to follow the principles depicted in the illustration below.

If we were sailing off the wind, with little or no leeway and neap tides, as a rule of thumb our circle of uncertainty radius should be 5% of the distance travelled since the last reliable fix we made.

If sailing on the wind, there’s some leeway and spring tides: radius of circle of uncertainty = 10% of distance travelled since last reliable fix

If sailing on the wind, there’s leeway and spring tides, the radius should be 10% of the distance travelled since the last reliable fix.

If sailing in heavy weather, hard on the wind with a lot of tacking, work on a radius of 15% of the distance travelled since the last reliable fix.

If sailing in heavy weather, tacking frequently or in fog: radius of circle of uncertainty = 15% of distance travelled since last reliable fi x

It is essential to monitor depths carefully, particularly in poor visibility, and especially after a long passage and approaching a shore.

By working on a circle of uncertainty you should be keeping an open mind about your position.

Never assume that you are within or really close to your estimated position triangle unless you can support this position with compass bearings and/or soundings.

7. Shoot-up drill

Let’s assume you’re trying to find an isolated danger in less-than-ideal visibility.

You have managed to get a good fix from three, fairly close, prominent objects, but are unable to locate the Twin Rocks at a height of 19m some 3.5M to your south-west.

So, having placed your fix on the chart, you measure the bearing to the Twin Rocks as being 247°(T), you convert this to magnetic by adding the variation of 006° W to give 253°(M).

Going up to the cockpit, you swing your hand-bearing compass round until you read as near as dammit 253° in the window, and with luck you
should be peering straight at Twin Rocks.

8. Back bearings

Working out which way to turn if relying on a back bearing is not so easy.

Here, the pilot is trying to keep on a course between a safe water mark and a southerly cardinal with a bearing of 180°(M) to the safe water mark.

Let’s assume the tide has taken him off course, that there is some advection fog and the cardinal cannot be seen.

The drill is to sight along the bearing of 180°(M) and see which side of the bearing the mark lies, then all he has to do is turn to bring that mark onto the correct back bearing, in this case by turning to starboard.

Avoiding errors: double check

Even the most experienced navigators make errors, which is why it’s essential that you check your plan carefully, and then check it again.

The chart to the left is correct: heading towards East Pow cardinal on 011°(M), if the bearing decreases we should turn to port, if it increases we should turn to starboard.

Pilotage: the dos and don’t

Do

• Get someone else to check your pilotage plan beforehand.
• Mark up your chart with bearings and distances.
• Check all equipment before setting off.
• Pay attention to shipping in busy estuaries and ports.
• Try to observe a couple of legs ahead the whole time, if the geography allows you.
• Always enter an unfamiliar and tricky harbour on a rising tide if possible.
• Always be aware of which side of your intended track you are

Don’t

• Be a slave to your plan: be aware of what is happening around you.
• Press on regardless if you are uncertain of where you are. Heave to or even drop the anchor so that you can check where you are.
• Pass too close uptide or upwind of dangers, buoys or obstructions.
•  Forget that buoys may be missing, misshapen or unlit.
• Rely solely on your engine: have your anchor prepared and sails ready.

Why you should still make a passage plan

Cruising guide author Robert Bailey explains the importance of not being completely dependent on electronic chartplotters and why it is…

Blind navigation: how to find your way in restricted visibility

Is blind navigation a foggy notion for Yachtmasters, or a useful seamanship skill? PBO investigates

Pilotage: 14 ways to get a fix

14 traditional pilotage tips to help you obtain and maintain a fix of your position

Crossing the Channel: 10 factors for a trouble-free voyage

What could go wrong while crossing the Channel? Ken Endean considers possible difficulties

Essential shorthanded sailing skills

Many sailors sail shorthanded much of the time, and it can prove a challenge. Rupert Holmes has some tips and…

Want to read more seamanship articles like this?

A subscription to Practical Boat Owner magazine costs around 40% less than the cover price.

Print and digital editions are available through Magazines Direct – where you can also find the latest deals.

PBO is packed with information to help you get the most from boat ownership – whether sail or power.

• • • • Take your DIY skills to the next level with trusted advice on boat maintenance and repairs
      • Impartial in-depth gear reviews
      • Practical cruising tips for making the most of your time afloat

Follow us on Facebook, Instagram, TikTok and Twitter