PENTARGON ... SPRINGER
 

... ... ... Seven years in an unassuming narrowboat on the waters of the "longest, friendliest village in England"  


... written to show skippers of narrowboats how to deal with any river creek on a tidal estuary. The method was developed on the  Thames and used to access Barking Creek without using the lock, enter and explore Dartford/Crayford Creek and to enter Bow Creek from upriver or down river  . . . in all cases using a 36' 1973 Springer with a Lister SR2 running at no more than about 1000rpm, delivering about 6HP and doing about 2kts over the water.


I was born by a tidal estuary (Colligan River at Dungarvan) , grew up by  another , sailing boats from childhood and learning the ways and wiles of tidal estuaries over decades. I had even crossed the Shannon Estuary, using tides, by descending the Ratty River from Bunratty and proceeded all the way to the further shore and back. On a blow up inflatable!  At the turn of the century I came to live by the Thames estuary and learned from old rivermen, lightermen, ferry skippers and amassed an enormous amount of practical hydrometry from assorted old codgers on many trips up and down the Estuary as a volunteer engineer/navigator on the sail-trainer "Kenya Jacaranda and as a volunteer with the London unit of the Maritime Volunteer Service where I learned the Thames from Teddington to Southend. The old men showed me tricks that have yet to appear on the web or even in books. Maybe I should start writing?  Getting my own boat in 2012, I realised its potential as an Estuary Explorer. Pentargon was a very unusual build as narrow-boats go and detailed study brought to light that the hull had been constructed using ship-building techniques. Dammit Pentargon is a ship. so once I became a boater, I punted a narrow-boat which could go down to the seas I'd come from and duly registered her as a small ship. Her unique features were exploited to the full in various ascents and descents of the Thames from Teddington or Brentford to Limehouse or Bow using the tides to carry the boat hither and thither before venturing further downstream.


RIVERCREEK

"Rivercreek" is inspired by Martin Ludgate's article "Up the Creek" from the August 2018 issue of Canal Boat, where he credited Pentargon as having kick-started the possibility of using Dartford Creek down the tidal Thames as a destination for intrepid canal boats.

 
HOW TO NAVIGATE A TRIBUTARY OF A TIDAL ESTUARY ON DIESEL FUMES
 Among the many adventures undertaken by Pentargon during her seven year English odyssey was to take tides down estuaries and use the flowing of waters to haul the hulk up unsuspecting rivers, with the flow and [sometimes] against the odds. The serious side of this game began with an initial visit to Dartford Creek during the Spring of 2015 which involved going down the Thames to Crayford Ness and blundering up Dartford Creek to a safe haven and a stay over. 

"CANAL BOAT
Martin Ludgate, in an article on the potential development of Dartford Creek, in the August 2018 issue of "Canal Boat"  tersely reported that "a first waterborne visitor, narrowboat Pentargon Springer, was followed by others". Fair comment, but the real truth is probably interesting enough to share with you. Dartford volunteers had excavated an old mooring bollard from beneath forty years of neglect to provide a purchase for Pentargon's lines on her first visit: the first boat in almost forty years to overnight in Dartford Creek. Pentargon tied up alongside at 5.30pm on the 26th April 2015, having descended on a wing and a prayer from Bow Lock with the skipper and three intrepid London boaters on board.  Much pre-planning and surveying had gone into the months prior to that first arrival. 

Over many years, IWA boaters had taken boats up Dartford Creek and back again on a single turn of tide, scurrying back to The River while they still had water under their keels. There was no evidence that anyone had gone up the Crayford Arm and certainly no admission that anyone had ever stayed over in the Cray for a tide or twenty as Pentargon did on a number of visits that first year.  There is inconclusive evidence that members of the St.Pancras Cruising Club may have visited Crayford or at least knew how. The "Tuesday Night Club" had made a visit up the Dartford arm with Steve Haywood hitching a ride but I have yet to nail the full story! Conrad Broadley brought his sloop up Old Crayford Basin in 2006, constrained by draught. He DID overnight though, even though he had to leave with the tide at 4.30am!


WHERE WAS PENTARGON WHEN THEY DID NOT NEED HER
Pentargon missed the 2018 Dartford Nautical Festival. She had completed her greatest adventure of them all: the biggest British Waterways ring ever attempted and achieved by a solo boater.  As the 2018 Festival got under way at Dartford, Pentargon was resting fifty miles upstream in Nauticalia's yard at Shepperton. In June 2017 Pentargon was on the Staffordshire and Worcestershire Canal at Gailey Wharf being modified by Jamie Ferguson to comply with "ClassD" inland waterways use, which is a class higher than i would ever use. 

(All of the tidal Thames between Teddington is "Class C" and unbelievably all of the Bristol Channel inside Portishead is also!) 
Later, in August 2017 Pentargon would take the tide from Sharpness to Bristol using the Dartford Technique, solo and pilotless.  


INTREPID ST. PANCRAS CRUISERS 
Reports on the methodology used to get the London adventurers to Dartford for the 2018 festival was noted with amusement by this scribe. No-one from that auspicious and intrepid group had considered contacting the one sailor who knew the Creeks and the Thames intimately. Outside the Dartford group no-one knew that Pentargon had made multiple visits to the Creeks in 2015 and 2016 and had stayed over for weeks at a time while on a C&RT licence. I did all the tide surveying, depth sounding and observed how the tide interacted with the river.  I'd moored by Steam Crane wharf, pitched up on various berms. I'd explored Crayford Creek in all weathers and at all stages of tide to see what could and could not be done with a 36' narrowboat in uncharted waters.




DESCENT TO DARTFORD
The first descent to Dartford was done by exiting a very early Bow Lock at the top of a tide which flowed us out to sea without any fuss or bother. Minimal science was used that day.  We had planned to arrive at the mouth of the Darent about 11oc, when the Tilbury tide gauge would be reading about 3m and dropping away. We nosed the boat into the creek once we had cleared Crayfordness and drove the boat aground in the channel. The bed of the Darent is higher than the surface of the estuary so the tide could ebb away all it wanted to and enter its next cycle. Pentargon would be going nowhere for the next three hours or more simply because it had been grounded. Once the tide returned, we would be floated up and, as the tide continued to rise, the back flow in the creek would push us upriver. Bit by bit we proceeded up stream, stopping and starting on repeated groundings as time and tide lofted us higher and further inland. About 4.30pm we came to our last grounding. Just below Bob Dunn bridge is a massive shoal of Kentish mud. Once through that, the boat began to move forward with less and less stops until we were in sight of the lock and the quay and the welcome party who could not understand what was taking us so long.  Here another massive mudbank caused by the lock itself and forty years of neglect stopped us awhile. We got in to the quay about 5pm but could not breast the cill just yet. So we tied up in the lock and were warmly welcomed to Dartford by the Friends of Dartford and Crayford Creek. The boat crew had had a long day, so they took off for the railway station and Oystered their way back to London in time for tea. I waited for another hour or so and slipped over the cill as soon as the 24" draft allowed. We were "home and dry" as it were. During the night I played with the lines as the night tide flowed and ebbed.
 
TAKE IT AS GIVEN ...
... the bed of a tributary is by definition higher than the main river.
... you can go be powerless and go up a tributary on a rising tide. 
... the vice is versa and punching is for boxers and leather workers

However, it is not always obvious that the tributary itself has its own flow, dependent on how much rain is falling in its basin [or not] and how much water is being nicked upstream [or not]. The height of tide appropriate to Dartford is measured fro9m the nearest tide gauge Tilbury, five miles downstream from the mouth or eight if you are at the cill by the lock. Water commences flowing over the cill when Tilbury is reading a REAL 5meters.
It took weeks of comparing tidal predictions with real-life measurements to establish this gem in 2015 and since I did not want to get on the collective nerves of London VTS staff at Gravesend by phoning them up frequently, I had to make an aerial tall enough to read their half hourly broadcasts or walk along the river dyke to where my handheld VHF could get a strong signal. Both methods and others were used at first. 

 There was no published data to fall back on. All the Hufflers were long dead, the last lock-keeper was frail. I got to meet him and his children but the knowledge was gone. Actual figures had to be dug out of nowhere. Even the Royal Navy had nothing to offer. They wanted to forget all about Dartford Creek for reasons best kept mum.
 
RISING TIDES LIFT ALL SHIPS
Pentargon needed more than 4m at Tilbury to enter the creek cleanly without grounding and to enjoy a continuous run upstream where 5.6m would let her to scrape over the cill. Fine tuning showed that cill tide happened about 20mins after Tilbury. Coming and going showed that it took Pentargon about half an hour from the mouth to the town side of the lock to the steam crane wharf. Back in the day when all the greaseproof paper in England was made there and Dartford was a thriving town bloated by paper making and pharmaceuticals, the steam cranes lifted the raw material in and the finished paper out and the hufflers brought their lighters up with light poles and very little muscle power.
 
TILBURY GAUGED
Tilbury 6.3m was another crucial measure for me. This was the height that allowed Pentargon to float on to and off various berms and effectively dry out under the boat when the tide receded. Tilbury6.9m was the highest tide recorded at any time during my stays and in practice anything over 6.2 was rare. This meant that at times when Pentargon was aground, she might not be able to come off for months. It did happen once and very nearly prevented her from leaving the Creek late in October of 2016 which might have been a disastrophe (stet). Another variable for users of any of the main Thames tributaries is the Thames Barrier.  It is in the gift of the Environment Agency to monitor weather and tides in the estuary and act on such knowledge. About once a month they test the system by closing the barrier, dropping the Barking and Dartford cills and, of course, whenever or if-ever there's a flood threat to London, the order goes out to do it for real and that gets on the news.

THE DARTFORD TECHNIQUE

  The basic method for getting into Dartford is to approach from seaward on a rising tide. If you've come down from London, moored or delay  somewhere downriver Greenhithe is good. You can listen to London VTS on Ch69. You can use the buoys there but they are chargeable. I usually drop an anchor on the land side of the buoys. Staying afloat tells you what the tide is doing. Once Tilbury has passed 3m rising you can let go and drift gently up the Kent side past Littlebrook Chimney. There is no reason to cross over.  In fact I would not recommend it. You are a narrowboat fogodsake. Your draft is a meter or less. You are defined as a "pleasure craft" and, if you are under 42' you don't even need a radio although this scribe likes to keep the PLA sweet.  Letting the tide drift you up from Greenhithe, you'll approach Crayford Ness about 3/4hr after weighing anchor with the tide near enough to 4m at Tilbury and running well in its third hour. You do know your rule of twelfths, don't you? Since you are well inshore and in shallow water, you needn't worry about the flow.  The Dartford Channel will be very obvious when you get to it from the Kent side, whereas it is very difficult to get it right if you had come up the Essex side and try to cross at ninety degrees following the book. Trust me on this one, you WILL miss your turn off or have to use mighty power to describe a parabola because you paid no attention to what i have been telling you so far. Let the tide work for you and steer yourself in gently. Dartford Creek is filling, Tilbury will have passed 4m with the flow increasing [rapidly] over the next 30mins as you drift along. My own experience of water speeds is that you may get 2kts between the barrier and the Crayford turn off and then 1kt through Bob Dunn.You will reach the lock with Tilbury 5m+ and the rule for getting over the cill is to add your draft to 5m. Pentargon draws 0.6m so can cross at Tilbury 5.6m. Most narrowboats have their deepest point over the tiller; certainly Pentargon does, I can stick the bow over the cill from about Tilbury 5.3m and the rising tide will slowly ease me over in its own time.
 

  SERIOUS STUFF NOW

Pentargon used a variation of the Dartford Technique to get up the River Avon to Bristol after overnighting on the tide outside Portishead in the Hole. The artist Hillary Kington totally captured "The Hole" as I found it, but I have to admit I did not get to see the wildlife as I slept right through the night and slipped away in the early morning as soon as the hole began to flood. The Avon Technique introduced extra dimension developed overnight by studying what charts and maps and tidal predictions were onboard added to my observations coming in. 

The Avon is a big river whose outflow was quite easy to feel coming down on the Saturday. Inside the Kings Road the outgoing tide grabbed the river and poured it down inshore so I eventually ended up east of the pier and travelling west to fetch up in the fairway channel close by but not in the hole. About 8pm, as the night tide began to flood, I had brought Pentargon off the fairway, not too far and ploughed her into the mud using the conventional method. Since, at that time, I could see all the mudbanks which would later be covered and had beached her, I knew it was safe underneath. AND. I had had a chance to observe the shape of the hole earlier when the fairway was dried out! I knew I would be safe all night. 

My tide tables and last night's observations confirmed that I would be able to float off at 8am, and that there would be a tidal flow towards Avonmouth harbour wall in the second hour. I also knew that the Avon would be flowing out to sea. Here my experience of tide fighting river and land became critical. By moving the boat off a little and pointing it directly at Avonmouth Harbour wall, I knew the tide would take me towards the wall and I would lose the river under the tide for long enough to gather my wits. 
 
Don't ask me why rivers do this. In theory, fresh water is less dense than saline water. In reality the sea tends to flow over the river at a confluence. Ok! So the Amazon is an exception and stays fresh for over 200 miles out into the southern Atlantic. But this is not the Amazon; this is the Avon. So I fetched up at the harbour wall just as the first of the tide was erm bouncing off the wall to go upstream. All I had to do was stay close to the wall and tiptoe along watching for the boundary between the river coming down and the sea bullying its way up. I found the boundary quite easily and was able to manoeuvre Pentargon along staying well in the saline. It is not a good idea to mess with this boundary. The slightest intrusion of the bow into the river could turn the boat on a sixpence, pulling the whole boat into the outgoing river and sending her down towards the sea at a trot.

With the building tide however, and the Bristol Channel tide is an aggressive tide, the boundary began to fade and the tide took charge before Pentargon had gone a mile upstream and upstaged the river completely. The rushing tide then shot myself and my boat up the gorge at such a speed that I covered the six miles to the holding point in less than an hour. The rest of the story is in the "Day to Day" blog here