Deben and Ore entrances - update

[PeterR]

Re Deben Bar

Locals may find my video sheds a little light on the available water on the Deben bar. Like most others I was keen to find out just how much water there was in the channel at chart datum. You need to see the video to get the detail but in essence, based on data from others, there is probably a channel with a minimum depth of about 0.3 metres at chart datum but I didn't find it. At the point I crossed the shallowest part of the bar on the way out (just after passing between Deben and Spit Knoll buoys) - I was down to 2.7 metres total depth when, using the Tide Times graph for Woodbridge Haven, the height of the tide should have been 2.8 metres (surge was only 0.01 metres). Using the same method for calculating tidal height when a friend crossed on another occasion he recorded 3.6 metres when I calculated tidal height was 3.3 metres. At that time the Harwich Tidal gauge was showing 3.6 metres – an exact match for his recorded depth. When I crossed the gauge was showing 3.0 metres i.e. 0.3 metres too optimistic.

Until someone can demonstrate exactly where this deep channel is and how to stay in it I would advise you assume the channel is awash at chart datum and plan accordingly.

If you plan your crossing on that basis the channel seems wide enough. The main danger I found was that, one and a half hours into the ebb, if you are trying to stay fairly close to West Knoll buoy in the narrowest part of the channel the four knot outgoing tide is doing its best to wash you straight into the buoy, the cross tide effect does not set in till further on.

 

[Johnah]

Interesting comments Peter and your excellent video shows how the fierce ebb sets you to the South. Agree with your comments that the channel is narrow and the depths around the Deben and Knoll Spit buoys vary considerably.

Also agree to plan for the minimum depth at chart datum and any extra depth is a bonus.

I went over the bar again on Thursday 18th May from 2 hrs before HW returning at 1 hr before HW and found a deep section close to the Deben buoy where the depth was marginally greater than at the bar itself. But how wide this is and whether I could find it again I don't know.

I do make sure however that I keep well away from the Knoll Spit buoy as the sinker appears to be set right on top of the spit and awash at LWS. You found shallow water in that area so maybe that was part of the spit.

This photo was taken on 22nd Feb and although the buoys were in their 2022 positions, it does show the Knoll spit on the LHS. Of course it may have changed considerably since then, but it does indicate how narrow that section is.

 

[PeterR]

Thanks John. I had seen your previous comments about the possible positioning of the sinker for Knoll Spit and did not get very close to it because of that but I agree I could have gone a lot closer to the Deben buoy. However, you also commented that your shallowest recorded depth could have been because you might have strayed too far north. What's a body to do?I'll try a going closer to the Deben buoy next time and see what happens. The fact that my recorded depths went up as soon as I turned to starboard was probably because by then I would have cleared the tip of the knoll. At the speed I was going with the tide underneath me it took just three minutes from passing between Deben and Knoll Spit to clearing Mid Knoll.

 

[MikeBz]

It would be interesting to see if there is a correlation between the depth over the bar and the live tide gauge at Felixstowe pier - one might imagine this would give a better correlation over the tidal range than Harwich.

 

[rwt]

Came into the Deben yesterday afternoon, a little under two hours before high, avoiding the (well marked) group of pot lines near the Haven buoy. I thought it was easier than last year (the only other time I have been in the river) except for the cross tide which was easy enough to allow for. The Martello tower is definitely useful in that respect. Now all I have to do is get out again!

Oh and grateful thanks to all concerned with the advice and chartlet.

 

[rwt]

Wimped from coming out on Monday and yesterday, anchored at the Rocks instead, did it this morning. New entrance (exit) definitely easier than the old one but still with its excitements. Great thing is you can see all the buoys before entering any shallow/rough water, even the Haven buoy, assuming normal vis of course. Now in Shotley supposedly for one night but the wind has come back up again this afternoon. Hey ho - its Summer tomorrow.

 

[curtius]

Came out an hour and a half after HW yesterday and saw a minimum depth of 3.3 metres. No problem, a bit bouncy due to the swell as we approached the Mid Knolls (green) but otherwise fine. Followed John White’s advice to stay close the Deben (green) and then move over to the West Knolls (red) before heading towards the Mid Knolls.

 

[Johnah]

Tried the bar again yesterday (11th June) in calmish NE2 weather at more than 3 1/2 hours before HW and a friend also came back in on a slightly different track. The Horse sand was covered and also the long outer North spit to the Mid Knoll Starboard hand buoy .

The minimum depth under the keel was just after the Deben buoy at 1.5m below the keel and 1.3m midway between the West Knoll port hand buoy and the Mid Knoll outer starboard buoy. My boat draws 1.6m so minimum depth was 2.9m and the Harwich tide gauge read 2.32m.

Coming back about 15 minutes later on a rising tide I had 1.2m beneath the keel in a slightly different part of the outer section and 1.3m again on the inner section near the Deben buoy.

My friend, on the slightly more Southerly track, had about the same depths so hopefully there is not a narrow trench that I was in. So 1.2m plus 1.6m boat depth = 2.8m minimum depth with the HHA tide gauge reading 2.46m above CD.

So the bar bed depth at present looks like it is 0.3m below CD - at least where we were.

Another sailing club yachtie with a very deep keep estimated a few weeks ago that it was even deeper at more than 0.3m below CD, but as we know, it is always changing.

My depth alarm is set to go off at 1m or less below the keel and it was silent both ways.

We take the minimum depth at the bar as being at least the HHA reading. This is a reasonably safe bet in calmish weather, then we add our own safety factor and don't stray off line.

Don't copy us, but check it yourself next time you come over the bar.

Just note the time and minimum depth and compare it the the HHA reading logged every 10 minutes here. https://hha.co.uk/live-data/tide/

Let us know your results.


John

 

[Bigplumbs]

Here is my trip over the Bar

 

[Johnah]

Photos of the Deben entrance on Tuesday 7th July at LW 0.3m above CD Harwich predicted only. There has been no live data on the HHA main site for the last few days.

The old channel is closing up and John White thinks that the shingle is moving towards the SH Deben buoy.

 

[MikeBz]

Superb pictures, especially the last one, thankyou!

 

[Cantata]

They are great pics. I'd hazard a guess that maybe there's another new entrance to come yet, north of the present buoyed one.

 

[DanTribe]

I have just downloaded ECPs excellent chartlet for the Deben entrance 29th March 2023.
Is this still the favourite route?
I had an idea that the buoys had been moved recently?
Can't say it often enough, I really appreciate the effort put into these chartlets.

 

[RivalRedwing]

I have just downloaded ECPs excellent chartlet for the Deben entrance 29th March 2023.
Is this still the favourite route?
I had an idea that the buoys had been moved recently?
Can't say it often enough, I really appreciate the effort put into these chartlets.

The chartlet worked for me a week or so back, buoys as per the chartlet. The entrance is straight forward although we had to contend with a sunken fishing vessel in the channel (but now removed)

 

[Cantata]

‘Favourite’ route? As far as we and the local harbour master are concerned, it’s THE route. The buoys have not been moved, the chartlet is correct.

 

[DanTribe]

‘Favourite’ route? As far as we and the local harbour master are concerned, it’s THE route. The buoys have not been moved, the chartlet is correct.

Thanks for the re-assurance. I must have misunderstood.