0:00:03 > 0:00:07This is the Lizard, the most southerly point of mainland Britain.
0:00:07 > 0:00:11For sailors on the high seas, this was the one piece of land
0:00:11 > 0:00:15they could reliably pick out as they tried to head up the English Channel.
0:00:15 > 0:00:19But this tranquil beauty spot was also a death trap.
0:00:21 > 0:00:25To avoid being wrecked, you have to know where you are.
0:00:25 > 0:00:30Think what it was like in the 1600s when you only had sketchy charts
0:00:30 > 0:00:34and when ships could be lured onto rocks by wreckers.
0:00:34 > 0:00:38Then, in 1693, along came Greenville Collins' "Coasting Pilot",
0:00:38 > 0:00:40the first complete survey of British coasts,
0:00:40 > 0:00:43their harbours and those treacherous rocks.
0:00:48 > 0:00:51But how did Collins do it? Over the next few days,
0:00:51 > 0:00:56I'll be sailing along the hazardous Cornish coast in the kind of ship Collins used.
0:00:56 > 0:00:59I want to find out the secrets of his achievement.
0:00:59 > 0:01:02How did he avoid shipwreck himself?
0:01:02 > 0:01:08And can I use his charts to navigate some of the most dangerous rocks and reefs in the world?
0:01:35 > 0:01:39What Greenville Collins did was to show the captains of great ships
0:01:39 > 0:01:42exactly where they were on the open sea.
0:01:42 > 0:01:45The rum lines which crisscrossed his maps
0:01:45 > 0:01:49provided the compass bearings needed to set an accurate course.
0:01:49 > 0:01:53For the first time, men who'd been in constant danger of shipwreck
0:01:53 > 0:01:57could work out the exact route they should take, the rocks to avoid
0:01:57 > 0:02:00and the directions to safe anchorages.
0:02:00 > 0:02:04It was the best possible guide to Britain's sea coast and harbours,
0:02:04 > 0:02:08and it revolutionised British chart-making.
0:02:10 > 0:02:15To find out how Collins did it, I've come to Cornwall,
0:02:15 > 0:02:18whose coast he mapped in the first year of his survey.
0:02:18 > 0:02:20I'll be sailing on the Phoenix
0:02:20 > 0:02:23from here at Charlestown to Falmouth,
0:02:23 > 0:02:25down to the Lizard, then from there
0:02:25 > 0:02:28to one of the deadliest offshore rocks, the Eddystone.
0:02:28 > 0:02:32The kind of place that sends a tingle of fear down your spine,
0:02:32 > 0:02:36not least because I'll be trying to sail there
0:02:36 > 0:02:40using techniques and instruments that Collins used 300 years ago.
0:02:54 > 0:02:58Back in the late 17th century, Britain was a huge sea power
0:02:58 > 0:03:03and all her imports and exports had to go by sea.
0:03:03 > 0:03:07But before Collins, the only published charts were Dutch
0:03:07 > 0:03:09and they lacked detail.
0:03:09 > 0:03:13At the time, the diarist Samuel Pepys was secretary to the Navy.
0:03:13 > 0:03:17He realised that British sailors were in desperate need
0:03:17 > 0:03:20of a new, much more accurate survey.
0:03:20 > 0:03:24Greenville Collins was given the task.
0:03:24 > 0:03:29Collins was chosen because he was a highly experienced Naval officer.
0:03:29 > 0:03:32He'd sailed as a captain in the South Seas,
0:03:32 > 0:03:35he'd fought Turkish pirates in the Mediterranean
0:03:35 > 0:03:39and, on a voyage of discovery to find a northwest passage to China,
0:03:39 > 0:03:42he'd been shipwrecked in the Arctic for two months.
0:03:42 > 0:03:46And he'd also produced maps of the South American coast,
0:03:46 > 0:03:51of the Mediterranean and of Falmouth. He was a man who was up for the job.
0:03:52 > 0:03:57Collins began with the English Channel,
0:03:57 > 0:04:00the most dangerous stretch of British coastal water.
0:04:00 > 0:04:04Britain was then at war with the Dutch.
0:04:04 > 0:04:07The Channel was their battlefield.
0:04:07 > 0:04:11Dutch privateers, the state-sponsored terrorists of the day, roamed the Channel
0:04:11 > 0:04:15looking for ships they could capture and hold to ransom.
0:04:15 > 0:04:20And, even close to shore, you could be attacked by Barbary pirates
0:04:20 > 0:04:25or drawn onto the rocks by wreckers who used fake warning lights
0:04:25 > 0:04:28to wreck your ship and steal your cargo.
0:04:28 > 0:04:32These were good reasons for plotting your course with care.
0:04:32 > 0:04:36But calculating your position at sea was fraught with difficulty.
0:04:36 > 0:04:40There was no reliable way of determining longitude,
0:04:40 > 0:04:44so you couldn't tell with accuracy how far east or west you were.
0:04:44 > 0:04:48And most ships, at some point on their voyage, got it wrong.
0:04:48 > 0:04:50It would be nearly a century
0:04:50 > 0:04:54before ships could fix their exact position mid-ocean.
0:04:54 > 0:04:58In the meantime, most ships tried to sail close to land,
0:04:58 > 0:05:01which gave them landmarks they could recognise.
0:05:01 > 0:05:04But it also increased the risk of shipwreck.
0:05:10 > 0:05:14Collins was convinced that accurate maps were the answer.
0:05:14 > 0:05:16He spent seven years
0:05:16 > 0:05:20producing 140 manuscript charts of the British coast.
0:05:20 > 0:05:25Question number one is how did you map a coast in the 1680s?
0:05:27 > 0:05:32Collins carried out a running traverse. So, what's that?
0:05:32 > 0:05:37Well, it means plotting coastal features from two angles.
0:05:37 > 0:05:42Put a cross where they intersect and that's the position of the feature.
0:05:42 > 0:05:45Join up the crosses and there's your coastline.
0:05:45 > 0:05:48With the help of first mate Luca Melzer,
0:05:48 > 0:05:52I'm going to have a go. First, I have to fix the position of the ship
0:05:52 > 0:05:56by taking a bearing from the ship to that headland over there.
0:05:56 > 0:05:59And I make that...to be...
0:05:59 > 0:06:02330 degrees from here.
0:06:02 > 0:06:07- So, Luca, should we transfer that bearing onto the sketch map?- Yes.
0:06:07 > 0:06:11We do that by lying the ruler on the chart
0:06:11 > 0:06:14from the headland back towards our position.
0:06:14 > 0:06:17We read off 330 degrees, draw the line.
0:06:17 > 0:06:22I would say the distance from here to that headland is about...
0:06:22 > 0:06:24- half a mile.- That's about right.
0:06:24 > 0:06:27'The distance from the coast doesn't have to be precise,
0:06:27 > 0:06:34'because what really matters is getting the exact position of the coastal features right.'
0:06:34 > 0:06:37This is a perfect example of a piece of coast that needs mapping,
0:06:37 > 0:06:41because you've got a port sitting between two very dangerous capes
0:06:41 > 0:06:46and, off those capes, an even more lethal set of rocks.
0:06:46 > 0:06:51Next, I'm going to take a sequence of compass bearings radiating out from the ship
0:06:51 > 0:06:55at various points on the land that are essential to be mapped
0:06:55 > 0:06:58if a ship is going to sail along this coastline safely.
0:06:58 > 0:07:03If I start at the cape we've taken a bearing onto... So, 330...
0:07:03 > 0:07:08- Then I can see a bay at 310 degrees. - 310 degrees, yes.
0:07:08 > 0:07:11Swivelling round, I can see a number of rocks.
0:07:11 > 0:07:15- The first one's at...292.- 292.
0:07:15 > 0:07:18A real monster sticking up.
0:07:18 > 0:07:21'This is a fantastically detailed exercise,
0:07:21 > 0:07:25'particularly with the ship bobbing around.
0:07:25 > 0:07:30'And these are nigh-on perfect conditions. Imagine doing this in a big swell!'
0:07:30 > 0:07:34- How about using the first house? - On the cliff?
0:07:34 > 0:07:39The left-hand end of the harbour wall we should have, shouldn't we...?
0:07:39 > 0:07:42- 225.- 225, you say?
0:07:42 > 0:07:44225, yes.
0:07:44 > 0:07:49Then we've got rocks like crests. I'll start at the left-hand side.
0:07:49 > 0:07:512...
0:07:51 > 0:07:54- 215.- 215.
0:07:54 > 0:08:01- In the middle, the highest point sticking up, even above high tide, is 210.- 210.
0:08:01 > 0:08:06So that's the full round. Next thing to do is to lift the anchor
0:08:06 > 0:08:09and sail in a dead straight line along the coast,
0:08:09 > 0:08:11measuring the distance we cover.
0:08:16 > 0:08:18- Easy.- Easy.
0:08:18 > 0:08:20'And that poses another challenge.
0:08:20 > 0:08:25'For the chart to be accurate, I have to know the exact distance I travel
0:08:25 > 0:08:30'between the two fixed anchorages. And how do I work THAT out?'
0:08:30 > 0:08:32There are two measurements we have to make.
0:08:32 > 0:08:38The first is to record the time taken for the ship to sail between its two fixed points.
0:08:38 > 0:08:40For that, we'll use an hourglass.
0:08:40 > 0:08:44The second measurement we'll take is the ship's speed.
0:08:44 > 0:08:46For that, we use this - a ship's log.
0:08:46 > 0:08:50It's a wooden plate which acts like a brake in the water
0:08:50 > 0:08:54and is attached to a line with knots in it. Hence "knot" for nautical speed.
0:08:54 > 0:09:00I sling this in the water... and I feed the line out till I get to the first knot.
0:09:00 > 0:09:05These knots are spaced so that a ten-second runner will give us a speed in nautical miles per hour.
0:09:05 > 0:09:09If I hold this knot here and we start the ten-second timer now,
0:09:09 > 0:09:11and I release the line...
0:09:11 > 0:09:16and I count the knots as they run through my hands... One knot...
0:09:17 > 0:09:19We must be approaching ten seconds.
0:09:19 > 0:09:22- Here's a second knot... - Ten seconds.
0:09:22 > 0:09:24Two nautical miles per hour.
0:09:24 > 0:09:27I know how fast we're travelling.
0:09:27 > 0:09:32Now I'll wait to see how long it's taken us to travel between the two fixed points.
0:09:32 > 0:09:36I'll then know what the distance between those two points is.
0:09:40 > 0:09:44Well, we've dropped anchor at the second of two fixed points
0:09:44 > 0:09:48and now I have to identify all the same landmarks on the coast
0:09:48 > 0:09:50and take the bearing to each of them.
0:09:52 > 0:09:55Right, let's get the first headland in sight...
0:09:55 > 0:10:00'We've sailed for half an hour, so the distance between the two anchorages
0:10:00 > 0:10:02'is one nautical mile.
0:10:02 > 0:10:06'If I put that calculation together with the two sets of bearings,
0:10:06 > 0:10:08'I should get my coastline.'
0:10:08 > 0:10:13Well, this is the moment of truth. We've got both anchorages mapped.
0:10:13 > 0:10:17Here's our first anchorage... Second here. Radiating out from each
0:10:17 > 0:10:20are all the bearings I took from both.
0:10:20 > 0:10:24Now, where these radiating lines intersect - here, here and here -
0:10:24 > 0:10:26those are my landmarks.
0:10:26 > 0:10:30So, in theory, if I join up all these intersecting rays,
0:10:30 > 0:10:35I should get the coastline that we're moored just off.
0:10:35 > 0:10:40That's one headland...two headlands, then around the coast are rocks...
0:10:40 > 0:10:43Now, here's the inlet,
0:10:43 > 0:10:47the sheltered haven. Then it comes round here
0:10:47 > 0:10:52and the coast comes all the way out towards the far headland.
0:10:52 > 0:10:57Then there's one other very important feature to map - the rocks.
0:10:57 > 0:10:59There they are.
0:10:59 > 0:11:02I've managed to map one nautical mile
0:11:02 > 0:11:06but it's taken the best part of a day in perfect conditions.
0:11:06 > 0:11:11No wonder it took Collins seven years to map the entire British coastline!
0:11:11 > 0:11:14I think I deserve a drink after all that.
0:11:14 > 0:11:17That means a quick trip ashore.
0:11:28 > 0:11:32Imagine you're a sea captain coming in out of the Atlantic in a gale.
0:11:32 > 0:11:36You've rounded the Lizard and you urgently need a safe haven.
0:11:36 > 0:11:39You look at Collins's chart of the English Channel and see
0:11:39 > 0:11:42there is a place called Falmouth,
0:11:42 > 0:11:46so you turn to the Falmouth page in the Coasting Pilot...and here it is,
0:11:46 > 0:11:50and what you find is a beautiful large-scale map
0:11:50 > 0:11:52of the Falmouth anchorage
0:11:52 > 0:11:54with everything you need to know marked on it.
0:11:54 > 0:11:57I'm coming in from the south
0:11:57 > 0:12:00and the hazards are all laid out very clearly for me.
0:12:00 > 0:12:04For example, rocks - little black crosses, showing you where not to go.
0:12:04 > 0:12:07He's got the sandbanks and mudbanks
0:12:07 > 0:12:10marked with stippled areas, so I can't take my ship there.
0:12:10 > 0:12:14And the numbers all over this map refer to depths in fathoms,
0:12:14 > 0:12:17all over the main sailing areas.
0:12:17 > 0:12:22They range from 18 fathoms here to only half a fathom up here.
0:12:22 > 0:12:26So we know where the hazards are... Where do you drop anchor?
0:12:26 > 0:12:29Well, Collins has helped by putting
0:12:29 > 0:12:32little anchor symbols in the places where it's best to drop anchor.
0:12:32 > 0:12:34Around Carrock Road are anchors
0:12:34 > 0:12:37where you can safely moor up for the night.
0:12:37 > 0:12:41Look at this incredibly beautiful cartouche in the top left-hand corner
0:12:41 > 0:12:43of the Falmouth map.
0:12:43 > 0:12:47In this cartouche are people going about their normal Cornish business.
0:12:47 > 0:12:51For example, there are two tin miners or lead miners.
0:12:51 > 0:12:53There's a fisherman picking up fish.
0:12:53 > 0:12:57There are two men putting what look like herrings in a pickling barrel.
0:12:57 > 0:13:01It was very difficult making money from the land and the sea then,
0:13:01 > 0:13:04so most of these characters were supplementing their income
0:13:04 > 0:13:07from another means - smuggling.
0:13:08 > 0:13:10'Well, it's been a long day,
0:13:10 > 0:13:15'but now I have a good idea of how Collins did his meticulous survey
0:13:15 > 0:13:18'and tomorrow I want to answer two more questions
0:13:18 > 0:13:20'about Collins's chart.
0:13:20 > 0:13:24'Can I really use it today to sail into Falmouth Harbour?
0:13:24 > 0:13:27'And was it any help in catching those smugglers?
0:13:35 > 0:13:38'Heading off to Falmouth now,
0:13:38 > 0:13:43'Collins's chart of Falmouth Harbour looks like an absolute masterpiece.
0:13:43 > 0:13:46'So, with the extra help of his written instructions,
0:13:46 > 0:13:51'can I navigate our way in?' Collins says the first thing to look out for
0:13:51 > 0:13:54is "Pendennis Castle, which standeth on a hill
0:13:54 > 0:13:57"on the west side of the harbour's mouth."
0:13:57 > 0:13:59He's also provided a shore profile
0:13:59 > 0:14:02which marks Pendennis Castle here,
0:14:02 > 0:14:04standing on a very pronounced hill
0:14:04 > 0:14:06to the left of the harbour entrance,
0:14:06 > 0:14:08which is just here, and he's written,
0:14:08 > 0:14:11"Thus showeth the going into Falmouth
0:14:11 > 0:14:15"when Pendennis Castle beareth north-west by north at two leagues."
0:14:15 > 0:14:17Two leagues is about six miles.
0:14:17 > 0:14:20We'll be coming into Falmouth at much closer in than two leagues,
0:14:20 > 0:14:23but the view should be the same. All we've got to do
0:14:23 > 0:14:25is spot Pendennis Castle on the shore
0:14:25 > 0:14:28and line ourselves up for a north, north-west approach.
0:14:47 > 0:14:51The Phoenix has reached exactly the right location.
0:14:51 > 0:14:54I can see all the features that Collins told me to look for.
0:14:54 > 0:14:58Here's Pendennis Castle, with its round tower, and there it is there.
0:14:58 > 0:15:01The hill profile's the same, although Collins exaggerated the sloping
0:15:01 > 0:15:04so it would catch seafarers' eyes.
0:15:04 > 0:15:07To the right of it, the harbour entrance,
0:15:07 > 0:15:09and above it is a wood that I can see
0:15:09 > 0:15:12300 years after Collins drew his charts.
0:15:12 > 0:15:15He warns us also of a rock
0:15:15 > 0:15:17"which lieth in the harbour's mouth
0:15:17 > 0:15:20"and lieth nearer the west shore than the east shore."
0:15:20 > 0:15:23It's called Falmouth Rock and it's incredibly dangerous
0:15:23 > 0:15:25because it's invisible at high tide.
0:15:25 > 0:15:28Well, over there, I can see what looks like
0:15:28 > 0:15:31a danger beacon on top of some sort of submerged obstable
0:15:31 > 0:15:34and I think that's the rock.
0:15:36 > 0:15:42Collins indicates that the best route in is on the east side of this rock.
0:15:42 > 0:15:46"You may sail up the fairway keeping your lead," he says,
0:15:46 > 0:15:49but how do you keep your lead?
0:15:50 > 0:15:53Time to learn a bit about checking sea depths with a lead weight.
0:15:53 > 0:15:57This looks like a child's skipping rope covered in coloured tassles.
0:15:57 > 0:16:01Can you reassure me that it's actually a navigational instrument?
0:16:01 > 0:16:04I can indeed. It's actually, if you look at it,
0:16:04 > 0:16:08- got markings all the way round... - Oh, yes.- This is a half marking -
0:16:08 > 0:16:10half a fathom, which is three feet,
0:16:10 > 0:16:14- and the further we go down... - That's one fathom.- One fathom,
0:16:14 > 0:16:17which is six foot. As we go down again, we'll find another fathom,
0:16:17 > 0:16:21with another six foot between it. What these would be used for...
0:16:21 > 0:16:24During the day, we wouldn't even have to haul it back up.
0:16:24 > 0:16:27We would be able to tell from which tassle was at the surface
0:16:27 > 0:16:29what our depth was
0:16:29 > 0:16:33and at night-time we'd pull the material out and put it in our mouth
0:16:33 > 0:16:37and you could tell the difference between the wool, cotton or leather
0:16:37 > 0:16:41- and get some idea of how deep it is. - Brilliant.
0:16:41 > 0:16:45The Phoenix needs at least three fathoms, or 18 feet,
0:16:45 > 0:16:49to sail into harbour safely, so exactly how much water is down there?
0:16:49 > 0:16:53The trick is to throw this without the coils getting tangled...
0:16:53 > 0:16:56This is called swinging lead?
0:16:56 > 0:16:58Swinging the lead, indeed.
0:16:58 > 0:17:01One...two...
0:17:01 > 0:17:02three!
0:17:02 > 0:17:06- Good throw, even if I say it myself. - Yeah. Excellent.
0:17:06 > 0:17:08- I felt it hit the bottom.- Did you?
0:17:08 > 0:17:12Wait till it gets to you. Haul it in until it's taut. There we go.
0:17:12 > 0:17:14Is that...?
0:17:14 > 0:17:16That's it there.
0:17:16 > 0:17:19- So we count from the cloth mark to the lead weight?- Yes.
0:17:19 > 0:17:21- That's one fathom...- Yeah.
0:17:23 > 0:17:24..two...
0:17:27 > 0:17:29..three...
0:17:30 > 0:17:31..four...
0:17:32 > 0:17:35- It's five fathoms. - Five fathoms. Exactly.
0:17:35 > 0:17:38'Five fathoms - about 30 feet.
0:17:38 > 0:17:40'That's perfect.
0:17:40 > 0:17:44'Incredible to think that using Collins's chart and directions
0:17:44 > 0:17:46'and a lead weight on a bit of rope,
0:17:46 > 0:17:49'we've navigated our way into Falmouth harbour -
0:17:49 > 0:17:52'more evidence that Collins's work is valuable today,
0:17:52 > 0:17:55'just as it was in the 1690s.
0:17:59 > 0:18:02'So, what about those smugglers?
0:18:03 > 0:18:07'I want to find some of the places they hid their contraband
0:18:07 > 0:18:10'when the Customs and Excise men were chasing them.'
0:18:10 > 0:18:12Line.
0:18:12 > 0:18:13Thank you.
0:18:13 > 0:18:17'Helford Sound is famous for its smuggling history.
0:18:17 > 0:18:19'Collins shows it as an inlet,
0:18:19 > 0:18:21'far too shallow for the Phoenix,
0:18:21 > 0:18:25'so if I'm going to investigate the accuracy of this part of the chart,
0:18:25 > 0:18:28'I'll have to find another way in.'
0:18:30 > 0:18:32- Hello, Chris.- Hello. All right?
0:18:32 > 0:18:36'Chris Bean was born and brought up on the Helford.
0:18:36 > 0:18:38'An experienced local fisherman,
0:18:38 > 0:18:42'he knows the estuary like the back of his hand.'
0:18:42 > 0:18:45So, does Collins's 300-year-old version of Helford
0:18:45 > 0:18:47match your modern mental map?
0:18:47 > 0:18:50Yes, I think from the point of view
0:18:50 > 0:18:53of an ocean-going sailing ship,
0:18:53 > 0:18:55the approaches are good.
0:18:55 > 0:18:57I think that the creeks
0:18:57 > 0:19:00are poorly indicated,
0:19:00 > 0:19:04but the smugglers would be quite happy to...
0:19:04 > 0:19:07see the lack of information on the places that really matter!
0:19:07 > 0:19:12- He left scope for Cornish smugglers. - Yeah. Maybe he's on the payroll.
0:19:12 > 0:19:15'The backwaters of the Helford are notoriously tricky
0:19:15 > 0:19:18'and far too dangerous for big ships,
0:19:18 > 0:19:21'so did the smugglers have a free run of it?'
0:19:21 > 0:19:25This is Frenchman's Creek, the most famous smugglers' creek in England.
0:19:25 > 0:19:29- Yes, I suppose it is. - Through Daphne Du Maurier's novel.
0:19:29 > 0:19:32Well, if you look around, you can see the little niches
0:19:32 > 0:19:37and hideaway places. You could see a vessel tied up under the bank...
0:19:37 > 0:19:40You could pull a rowing boat up under the boughs of the trees
0:19:40 > 0:19:43- and it would disappear instantly. - That's right.
0:19:43 > 0:19:47Especially at this time of year, with good foliage on the trees.
0:19:47 > 0:19:49Lots of camouflage for a smuggler's boat.
0:19:49 > 0:19:55It's such a long way from the main river that by the time you come up around these doglegs,
0:19:55 > 0:19:57nobody would know you're here.
0:19:57 > 0:20:02So this was both unmapped and a no-go area for the Customs and Excise?
0:20:02 > 0:20:04Yes, around these creeks
0:20:04 > 0:20:08there are footpaths and little bridle tracks
0:20:08 > 0:20:11back to the landowners and the local villages,
0:20:11 > 0:20:15so it would be easy enough to move stuff away by packhorse.
0:20:15 > 0:20:20Spirit barrels away... Feels like an Amazonian backwater. It doesn't feel as if we're in Britain.
0:20:20 > 0:20:22It's a lost world.
0:20:38 > 0:20:42Onto the next leg of my journey. I want to sail down to the Lizard.
0:20:42 > 0:20:46It was vital to sight the Lizard to get into the Channel.
0:20:46 > 0:20:50Too far south and you could run onto the rocks of Brittany.
0:20:50 > 0:20:53Too far north and you could be wrecked off Land's End.
0:20:53 > 0:20:56The Lizard is also the obvious place
0:20:56 > 0:21:00to start my really serious test of Collins's work.
0:21:00 > 0:21:02I want to see whether I can sail
0:21:02 > 0:21:07from the Lizard, off our starboard bow, all the way to Eddystone Rock,
0:21:07 > 0:21:0938 nautical miles over there.
0:21:09 > 0:21:14The Phoenix is bound for a single, lethal rock, out of sight beyond the horizon,
0:21:14 > 0:21:19but on the way I'm going to put 17th-century methods of navigation,
0:21:19 > 0:21:21and Collins's chart, to the test.
0:21:24 > 0:21:26To make it a bit more of a challenge,
0:21:26 > 0:21:29we're setting off just as the sun sets,
0:21:29 > 0:21:32so the journey will involve sailing overnight.
0:21:32 > 0:21:33To navigate,
0:21:33 > 0:21:36the process we'll be using all the way to Eddystone
0:21:36 > 0:21:39is called "dead reckoning".
0:21:44 > 0:21:48Dead reckoning means keeping a record of the speed and the distance
0:21:48 > 0:21:53you've sailed, but to do that you have to allow for the way the wind and tide can push you off course,
0:21:53 > 0:21:57because none of us want to end up as another wreck on Eddystone Rock.
0:21:59 > 0:22:03Of course, the other traditional navigational tool
0:22:03 > 0:22:05on a clear night...is the stars,
0:22:05 > 0:22:07but what do they tell you?
0:22:07 > 0:22:12Can they really put you on an accurate course in the dead of night?
0:22:15 > 0:22:18We've left the mainland behind.
0:22:18 > 0:22:21We're sailing out to sea. It's a beautiful, clear night.
0:22:21 > 0:22:24The sky's stuffed with stars, but where do you start?
0:22:24 > 0:22:28Um...the best way to start would be probably with the Plough,
0:22:28 > 0:22:32- which is part of the constellation of Great Bear...- Yeah.
0:22:32 > 0:22:36..the most conspicuous constellation in the northern hemisphere.
0:22:36 > 0:22:40You see you've got those two pointers,
0:22:40 > 0:22:44- the last two stars in the blade... - On the end of the plough?
0:22:44 > 0:22:46That's right. And they point
0:22:46 > 0:22:50straight towards Polaris, the North Star or the Pole Star.
0:22:50 > 0:22:55The Pole Star's standing up there all on its own, very clearly.
0:22:55 > 0:22:58It's in the constellation of the Little Plough.
0:22:58 > 0:23:00What does the Pole Star tell you?
0:23:00 > 0:23:02The Pole Star tells you
0:23:02 > 0:23:04the geographical pole,
0:23:04 > 0:23:08so if you are heading towards the Pole Star, you'll be heading north,
0:23:08 > 0:23:10and the other important bit is
0:23:10 > 0:23:15if you imagine the arc between the horizon and the Pole Star,
0:23:15 > 0:23:18that should give you a latitude, your latitude.
0:23:18 > 0:23:21So that one star will tell you
0:23:21 > 0:23:25your compass direction and how far north or south you are on the globe.
0:23:25 > 0:23:27That's right.
0:23:29 > 0:23:32'We could be in the 1600s.
0:23:32 > 0:23:35'This is sailing as Collins knew it.
0:23:35 > 0:23:40'A still night, steering by the stars...
0:23:40 > 0:23:42'the biggest map of all.
0:23:42 > 0:23:44'Magical!'
0:23:56 > 0:24:00We've been sailing all night on our dead-reckoning course,
0:24:00 > 0:24:03but I'm wondering now how much we've been pushed sideways
0:24:03 > 0:24:06by the wind and tide. Keith, are we on course or not?
0:24:06 > 0:24:08I think we're close to course.
0:24:08 > 0:24:11We've allowed for five degrees leeway for the effect of the wind.
0:24:11 > 0:24:14The tides we can't be so sure of.
0:24:14 > 0:24:16All this looks the same to me.
0:24:16 > 0:24:20We're in a huge expanse of open sea. I can't tell one bit from another.
0:24:20 > 0:24:23Have we got any way of double-checking our position?
0:24:23 > 0:24:27Yes, we have here an instrument which Collins would have had,
0:24:27 > 0:24:28which is a Davis quadrant.
0:24:28 > 0:24:31Is this a later version of the old-fashioned cross-staff
0:24:31 > 0:24:35- which used to burn out the eyes of navigators?- That's right,
0:24:35 > 0:24:40but this one works on the basis of using the shadow of the sun.
0:24:40 > 0:24:44- You stand with your back to the sun? - Correct.- OK. How do you use it?
0:24:44 > 0:24:48- Hold it in your right hand...- Is this the eyehole you look through?
0:24:48 > 0:24:52- Yes, which you line up with the horizon...- Got it.
0:24:52 > 0:24:55I can see the shadow.
0:24:55 > 0:24:58- Got the shadow on the slot...- And line up the slot with the horizon.
0:24:58 > 0:25:01This slides up and down this calibrated scale.
0:25:01 > 0:25:05OK, the shadow's meeting the slot meeting the horizon,
0:25:05 > 0:25:08so I now take readings off this scale. OK.
0:25:08 > 0:25:11- And add it to the scale on that side.- It says we've got
0:25:11 > 0:25:1449 degrees...55 minutes.
0:25:14 > 0:25:17And that would be reasonable.
0:25:17 > 0:25:20- Is that our latitude?- Yeah. - And is that the right bit of sea?
0:25:20 > 0:25:23- There or thereabouts.- I hope so.
0:25:23 > 0:25:25Don't want to hit the rocks.
0:25:28 > 0:25:32'Well, Keith seems confident, but I'm not so sure.
0:25:32 > 0:25:34'I'm going to take a look up top.
0:25:37 > 0:25:39'Strewth!
0:25:39 > 0:25:41'This is not for the faint-hearted.
0:25:42 > 0:25:46'One slip here and you're on the deck or in the sea.
0:25:50 > 0:25:54'Still no sign. We're obviously some way off.
0:25:54 > 0:25:59'Truth is I'm used to maps that show you exactly where you are.
0:25:59 > 0:26:03'Sailing to Eddystone 17th-century-style
0:26:03 > 0:26:05'seems a bit more hit-and-miss.
0:26:06 > 0:26:10'And I don't just want to see the rock. I want to land on it.
0:26:16 > 0:26:19'15 hours. It's been such a long haul.
0:26:19 > 0:26:23'We've just trimmed the sails to increase our speed
0:26:23 > 0:26:26'and I'm checking our course every five minutes.
0:26:26 > 0:26:29'We must surely be very near now.'
0:26:35 > 0:26:37There it is! Eddystone Rock.
0:26:37 > 0:26:4138 miles and 16 hours after leaving the Lizard, we've got here!
0:26:54 > 0:26:56OK, going for it...
0:26:56 > 0:26:58Going for it...
0:27:02 > 0:27:04Eddystone is the site
0:27:04 > 0:27:08of the world's first lighthouse to be built on an offshore rock.
0:27:08 > 0:27:10Work started here in 1696,
0:27:10 > 0:27:14just three years after Collins' Coasting Pilot was published.
0:27:14 > 0:27:16I got here!
0:27:42 > 0:27:46The extraordinary thing about Collins's life
0:27:46 > 0:27:48is that after all of his efforts
0:27:48 > 0:27:51the establishment turned its back on him and his ideas,
0:27:51 > 0:27:55alleging that his charts were not accurate enough.
0:27:55 > 0:27:57History has decided differently.
0:28:00 > 0:28:04Despite the establishment's dismissive attitude to his work,
0:28:04 > 0:28:06Collins's charts proved a huge success.
0:28:06 > 0:28:09They're a landmark in maritime history.
0:28:09 > 0:28:13They safely brought home ships and sailors for over a century
0:28:13 > 0:28:16and the charts we use today are their direct descendants -
0:28:16 > 0:28:18Collins updated, if you like.
0:28:18 > 0:28:21The Coasting Pilot confirmed Greenville Collins
0:28:21 > 0:28:24as a pioneer of modern hydrography,
0:28:24 > 0:28:27one of the greatest British map-makers of all time.
0:28:27 > 0:28:34Subtitles by Audrey Flynn and Suzanne Macdonald BBC Broadcast 2004
0:28:34 > 0:28:38E-mail us at subtitling@bbc.co.uk