Time difference between the start of the ebb in the River Avon at the entrance to Cumberland Basin and the ebb at Avonmouth

[Marsali_1]

I am wondering how long after the ebb tide commences at Avonmouth does it start to ebb at the entrance to Cumberland Basin? The tide tables show a ten minute lag in the times of HW but that doesn't mean that the flood is not still running for some additional period of time after.

 

[Bristolfashion]

I suspect that, as there's no large open body upstream of the Cumberland basin to generate an "over run", the current will pretty much change at HW Bristol.

 

[mattonthesea]

I suspect that, as there's no large open body upstream of the Cumberland basin to generate an "over run", the current will pretty much change at HW Bristol.

At high springs the river floods all the way to Keynsham. Bath has Saltford to the west and Freshford to the east

 

[Marsali_1]

At high springs the river floods all the way to Keynsham. Bath has Saltford to the west and Freshford to the east

Thank you to you and Bristolfashion for your replies. Would it be safe, then, to say that on springs the start of the ebb at Cumberland Basin will be later than at neaps and that at neaps it will start around HW?

 

[mattonthesea]

TBH I've never looked into it. The locking times dictated my travel so I went with them!

I once missed the inward lock time and had to overnight in Portishead. Bristol VTS let me know before I got to Pill

 

[Bristolfashion]

Thank you to you and Bristolfashion for your replies. Would it be safe, then, to say that on springs the start of the ebb at Cumberland Basin will be later than at neaps and that at neaps it will start around HW?

I'm sure sure about "safe" but it's a good working hypothesis - we found the Bristol Harbour master's office to be helpful - I'm sure they'd know.

There are also a couple of cruising clubs based in Bristol harbour - another possible source of info.

As mattonthesea says, the locking times define your travel times anyway.

 

[oldmanofthehills]

If you have only given yourself 10 minutes margin you will be stuffed in bristol avon or bristol channel. Slack can be a mere 20 minutes. As matt says, get to locks when harbour master requires it, which will be before HT

 

[mattonthesea]

Marsail, still not sure of the reason for your question but you've heard from three experienced old hands. Sorry if I'm teaching granny to suck eggs but here goes anyway. If it's your first time out may be worth seeing a ride out at Portishead. That covers you room to get your timing right. The marineros will advise. Approaching the Avon keep close in, out of the main tide and watch for shipping; they do weird manoeuvres approaching the locks! Head for the light house on the north wall until you think you'll crash into it. The Avon at this point looks like a wall of mud! As you approach the wall you can just make out the transit markers to turn up the river.

Once in the Avon you might think that you are going to arrive too early; you won't. As you go up river the current slowed considerably. If you have friends in Bristol then get them to meet you at the locks so they can take photos of you under the suspension bridge .

That's it from me. The rest of in the books. The others may have more to add.
M

 

[Marsali_1]

Marsail, still not sure of the reason for your question but you've heard from three experienced old hands.

Sorry, the original question was prompted by me doing some paper passage plans based on exit timings from Bristol. Iwas trying to determine which lock out would be the optimum (ie punching the least amount of unfavourable current in the river) to get me furthest down channel after leaving the Avon. Obviously nobody that read the question would know what was going through my mind, lol! I do appreciate the replies. Information on stream rates and timings does not seem to be available for the river between Avonmouth and Bristol and the local knowledge really helped.

 

[mattonthesea]

Sorry, the original question was prompted by me doing some paper passage plans based on exit timings from Bristol. Iwas trying to determine which lock out would be the optimum (ie punching the least amount of unfavourable current in the river) to get me furthest down channel after leaving the Avon. Obviously nobody that read the question would know what was going through my mind, lol! I do appreciate the replies. Information on stream rates and timings does not seem to be available for the river between Avonmouth and Bristol and the local knowledge really helped.

That's easy . The earliest lock out will take you, at 4 kts, about an hour and a half, depending on tidal cycle, to Portishead. There is a country current closer to shore of your wicker than that, about an hour before HW. That will get you towards Clevedon. From there you can get passed Porlock but there are no sensible stops that I know of passed there. Even the anchorage at Porlock is bumpy! We usually anchor off Minehead, having taken the last lock out. Then buck the last two hours of flood to get to Lundy.

If you do at Portishead then you can use the counter current to leave early and get 7 hours of fair tide. A little bit of foul tide and you can make the Gower.

Doesn't answer your question but hopefully helps.

M

 

[SaltIre]

The Tidal Stream Atlas for the Bristol Channel will surely give the answer.
NP256 - ADMIRALTY Tidal Stream Atlas: Irish Sea and Bristol Channel

 

[Marsali_1]

The Tidal Stream Atlas for the Bristol Channel will surely give the answer.
NP256 - ADMIRALTY Tidal Stream Atlas: Irish Sea and Bristol C

Thank you for the link but, unfortunately, it doesn't include the Avon between Avonmouth and the entrance to Cumberland Basin and that was the info I was missing.

 

[oldmanofthehills]

Hi Marsali, we now understand the question. on a low speed boat you are trying to manage the impossible on the english side. In the old days people just hung around and anchored in whatever pill or sheltered bay they could get to and it hasnt really changed. There are no viable lowtide harbours before St Ives and even thsts dodgy. i have anchored outside Minehead ( by the white rock) when coming from
Portishead but Blue Anchor bay is better shelter and anchorage and probably more within your reach from Bristol

Of course if you have 15kt mobo not a 5kt yacht, things are different.