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Sharpness to Bristol on the tide


PENTARGON SPRINGER

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15 hours ago, Wanderer Vagabond said:

 I have done quite a bit of offshore sailing and the guy I sail with did a sort of circumnavigation of England and Scotland, including a trip up to Gloucester docks. He sent me an e-mail about his exploits and when I told him that there are a few narrowboaters who go between Port'shead and Sharpness, his response was,"They must be barking mad", this was from someone I've crossed the North Sea with (twice). The currents under the bridges can be, shall we say, challenging:unsure:

 

Hundreds of narrow boaters do it every year almost all without incident. With reasonable weather, proper planning and a qualified pilot it's not really such an outrageous escapade. I think your yachty friend was over-reacting slightly.

 

I didn't notice any change in the current as I steered under the Second Severn bridge. The pilot was on the phone and had asked me to steer. The span is so wide and the supports so far apart there's no need to be anywhere near them. It's not like going through London on the tideway.

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22 hours ago, Alan de Enfield said:

That's one of the things you learn on a RYA  'Day Skipper' and in further depth on the 'Coastal Skipper' courses.

Imagine a boat capable of 4mph leaving (say) Southampton and planning to arrive at St Peters Port Guernsey - part of the examination is to calculate the duration of the trip, work out the course headings for each hour of the tide (both on ebb and flood).

Your course, on paper, looks like a huge Z shape but as the water is moving, and you are also moving 'across' the water, if you get it right, you make a straight line from A to B

 

Well worth doing if just to get an understanding of tides and navigation, - (just think, when we are 'cut off' from Europe, no planes and no ferries, we can still get there)

 

There is one of these tidal streams published for every hour of the tidal flow showing strength and direction.

 

Image result for channel tidal flows

Last summer my brother took his yacht across the Channel from Dartmouth, aiming for Paimpol.  He had hired an 'expert' but elderly Frenchman who had made several trans-ocean crossings.  As the got out into the open sea the guy insisted he should try to buck the tide.  Bruv told him he had done the trip 6 times before with experienced British yachtsmen in the same yacht, and he explained that they always headed the boat straight across, because the tidal currents would cancel each other out over the (approx 12 hr) duration of the crossing.  Frenchman threatened to have a hissy fit so Bruv went along with him.  Result was that they travelled twice as far through the water as necessary, and missed the landfall deadline of dusk.  They ended up scrabbling along in the dark looking for a different harbour, ending up on a mud bank on a falling tide in Lannion.   Luckily the boat was sound and survived, but the Frenchman swore he would never cross La Manche ever again, having lost his bottle as they were waiting for the boat to right again.  Fact is that the only true 'experts' are those with direct experience of the route.

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9 minutes ago, Murflynn said:

 

 

 

 

 

 

 

 

 

 

British yachtsmen in the same yacht, and he explained that they always headed the boat straight across, because the tidal currents would cancel each other out over the (approx 12 hr) duration of the crossing.

In principle you (he) may be correct, but in fact that is very dangerous and against the law.

If you are 'crossing' the Channel then you must proceed straight across and cross the TSS at 90 degrees, not slowly drift across using the tide at 45 degrees to the TSS and than drift back again at 45 degrees.

 

You will be spending an inordinately long time going the wrong way in the TSS.

 

A British boater was fined £6000 for doing just that and going the 'wrong way' up the TSS

 

An experienced delivery skipper who motored the wrong way for 15 miles inside a traffic separation scheme (TSS) has been ordered to pay a £6,000 fine plus more than £2,000 costs.

At approximately 10.40 a.m. the vessel entered the South West shipping lane heading in a north easterly direction against the general flow of traffic. The vessel continued in this lane for approximately 50minutes before exiting the South West lane and re-entering the Inshore Traffic Zone.

Coastguard Officers based at Langdon Battery, Dover Harbour, made a number of unsuccessful attempts to contact the vessel by VHF radio. A passing ship was able to describe the craft and the Coastguard aircraft was launched. Having left the lane Mr Choat became aware of the aircraft activity and answered a radio call.

The Chairman of the Bench said that there were four aggravating factors in this case
1. The speed and distance of transgression
2. The experience of Mr Choat
3. It was a commercial voyage
4. A significant error in navigation

In arriving at the fine they took into account his early guilty plea and co-operation with the MCA. It was also stated that if Mr Choat had not pleaded not guilty at the earliest possible opportunity then the fine would have been significantly higher.


 

Image result for Channel TSS

Edited by Alan de Enfield
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9 minutes ago, Alan de Enfield said:

In principle you (he) may be correct, but in fact that is very dangerous and against the law.

If you are 'crossing' the Channel then you must proceed straight across and cross the TSS at 90 degrees, not slowly drift across using the tide at 45 degrees to the TSS and than drift back again at 45 degrees.

 

You will be spending an inordinately long time going the wrong way in the TSS.

 

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It is only "against the law" as you say when traversing a TSS, and the route he specifically mentioned was from Dartmouth to Paimpol. You show the Dover Straights TSS which is not the area in question. Although it is a little while since I was in the area mentioned - Dartmouth to Paimpol -  I don't recall any specific TSS that they would have crossed on that route., and if not falling foul of any TSS's they would have been free to chose whatever safe course they liked.  Whether that would have been sensible is another issue:boat:

 

Howard

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When I made the crossing in a friend's yacht in 1971 the chart showed a huge area designated 'DANGER Submarine Exercise Area'.  Another Dartmouth yachtsman reported a submarine surfacing within 100 yards of him in a heavy swell and poor visibility, and believed it was likely that the sub might not have seen them through the periscope.  Scary!

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31 minutes ago, howardang said:

It is only "against the law" as you say when traversing a TSS, and the route he specifically mentioned was from Dartmouth to Paimpol. You show the Dover Straights TSS which is not the area in question. Although it is a little while since I was in the area mentioned - Dartmouth to Paimpol -  I don't recall any specific TSS that they would have crossed on that route., and if not falling foul of any TSS's they would have been free to chose whatever safe course they liked.  Whether that would have been sensible is another issue:boat:

 

Howard

I did - and when I realised it only showed the Dover end I deleted it (12 minutes before you posted so not sure how it picked up the 'original') and added the full channel scheme. which you will see still has separation when departing Dartmouth (we were in Dartmouth last Summer)

 

The TSS is simply to filter you into the correct 'lane' and once in that lane you stay in it.

heading 'across the channel the separation lanes should be crossed at as close to 90 degrees as possible 

 

Colregs 10

 

(a) This Rule applies to traffic separation schemes adopted by the Organisation and does not relieve any vessel of her obligation under any other Rule.

( b) A vessel using a traffic separation scheme shall:

(i) proceed in the appropriate traffic lane in the general direction of traffic flow for that lane;

( ii)so far as practicable keep clear of a traffic separation line or separation zone;

( iii)normally join or leave a traffic lane at the termination of the lane, but when joining or leaving from either side shall do so at as small an angle to the general direction of traffic flow as practicable.

( c) A vessel shall, so far as practicable, avoid crossing traffic lanes but if obliged to do so shall cross on a heading as nearly as practicable at right angles to the general direction of traffic flow.)

 

Colregs apply to the 'lanes' as well as the actual TSS

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1 hour ago, Alan de Enfield said:

I did - and when I realised it only showed the Dover end I deleted it (12 minutes before you posted so not sure how it picked up the 'original') and added the full channel scheme. which you will see still has separation when departing Dartmouth (we were in Dartmouth last Summer)

 

The TSS is simply to filter you into the correct 'lane' and once in that lane you stay in it.

heading 'across the channel the separation lanes should be crossed at as close to 90 degrees as possible 

 

Colregs 10

 

(a) This Rule applies to traffic separation schemes adopted by the Organisation and does not relieve any vessel of her obligation under any other Rule.

( b) A vessel using a traffic separation scheme shall:

(i) proceed in the appropriate traffic lane in the general direction of traffic flow for that lane;

( ii)so far as practicable keep clear of a traffic separation line or separation zone;

( iii)normally join or leave a traffic lane at the termination of the lane, but when joining or leaving from either side shall do so at as small an angle to the general direction of traffic flow as practicable.

( c) A vessel shall, so far as practicable, avoid crossing traffic lanes but if obliged to do so shall cross on a heading as nearly as practicable at right angles to the general direction of traffic flow.)

 

Colregs apply to the 'lanes' as well as the actual TSS

Thank you for the quote but I really don't need a lesson on the Rules from you, Alan, and it is certainly not necessary to quote them. I don't intend to get into one of this forums pointless point scoring exchanges, but I would suspect you know the point I was making in my posting which I think was perfectly clear, but if not, well hey ho, that's life.

Have a good evening.

 

Howard

 

 

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20 hours ago, Alan de Enfield said:

In principle you (he) may be correct, but in fact that is very dangerous and against the law.

If you are 'crossing' the Channel then you must proceed straight across and cross the TSS at 90 degrees, not slowly drift across using the tide at 45 degrees to the TSS and than drift back again at 45 degrees.

 

You will be spending an inordinately long time going the wrong way in the TSS.

 

A British boater was fined £6000 for doing just that and going the 'wrong way' up the TSS

 

An experienced delivery skipper who motored the wrong way for 15 miles inside a traffic separation scheme (TSS) has been ordered to pay a £6,000 fine plus more than £2,000 costs.

(snip)

If the heading of a crossing vessel when crossing the traffic lane is at 90 degrees to the lane, then the vessel will spend the least amount of time in the traffic lane, despite the course over ground varying due to the tide flow. If the vessel's speed and the tidal flow are roughly the same, then the crossing will indeed be at about 45 degrees. This is in accordance with the rules, in particular Rule 10 (c) of the Colregs

 

Quote

(c) A Vessel shall, so far as practicable, avoid crossing traffic lanes but if oblged to do so shall cross on a

heading as nearly as practicable at right angles to the general direction of traffic flow.

(my bold)

 

In the quoted case, if the offending vessel travelled 15 miles inside the traffic separation scheme, neither heading nor  course can have been anywhere near right angles to the traffic separation scheme!

 

edited to add : There is a difference between heading and course, and Rule 10 (c) states "heading".

 

Edited by Iain_S
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  • 1 month later...

I've had a good few laughs on this thread but nobody has answered the question I posed.

Is it normal to deviate from a Sharpness to Bristol transit by entering a submarine danger area in Le Manche?

Have a look at www.pentargon.webs.com for my own solution ...

and sorry,

I missed this post by 24H. YESTERDAY was April1

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On 02/04/2019 at 12:25, PENTARGON SPRINGER said:

I've had a good few laughs on this thread but nobody has answered the question I posed.

Is it normal to deviate from a Sharpness to Bristol transit by entering a submarine danger area in Le Manche?

 

 

I don't know the answer and don't even understand if it was some sort of joke, but perhaps the reason nobody answered that question is because you didn't pose it.

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On 02/04/2019 at 12:25, PENTARGON SPRINGER said:

I've had a good few laughs on this thread but nobody has answered the question I posed.

Is it normal to deviate from a Sharpness to Bristol transit by entering a submarine danger area in Le Manche?

Have a look at www.pentargon.webs.com for my own solution ...

and sorry,

I missed this post by 24H. YESTERDAY was April1

we like going off topic, innit?

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